Front Cover
 Title Page
 Earth, one name for two things
 Back Cover

Title: TropSoils, the first three years
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00054336/00001
 Material Information
Title: TropSoils, the first three years
Physical Description: Book
Language: English
Creator: Caudle, Neil
Affiliation: North Carolina State University -- Department of Agricultural Communications
Publisher: TropSoils, North Carolina State University
Subject: Farming   ( lcsh )
Agriculture   ( lcsh )
Farm life   ( lcsh )
Africa   ( lcsh )
Spatial Coverage: Africa
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Table of Contents
    Front Cover
        Front Cover
    Title Page
        Page 1
    Earth, one name for two things
        Page 2
        Page 3
        Page 4
        Semi-arid tropics
            Page 5
        The Sahel
            Page 6
            Page 7
            Page 8
        Soil survey
            Page 9
        The sandfighter
            Page 10
            Page 11
            Page 12
            Page 13
        Tiger bush, leopard bush
            Page 14
            Page 15
        A team effort
            Page 16
        Acid Savannas
            Page 17
        The Cerrado
            Page 18
            Page 19
        Reds and yellows
            Page 20
            Page 21
            Page 22
            Page 23
            Page 24
        Humid tropics
            Page 25
        The Amazon
            Page 26
            Page 27
            Page 28
        Paddy rice
            Page 29
            Page 30
            Page 31
        Unknown African
            Page 32
            Page 33
            Page 34
            Page 35
            Page 36
            Page 37
            Page 38
            Page 39
        A New way of Sorting Soils
            Page 40
            Page 41
            Page 42
        Sticking with it
            Page 43
            Page 44
            Page 45
        The settlements
            Page 46
        Life in Sitiung
            Page 47
            Page 48
            Page 49
            Page 50
        Reclaiming barren land
            Page 51
        Soils, crops and fertilizers
            Page 52
            Page 53
        Strips and spots
            Page 54
        Variability, piece by piece
            Page 55
        Page 56
    Back Cover
        Back Cover
Full Text

the first three years

the first three years

About TropSoils
TropSoils is a collaborative research program whose goal is to develop improved soil manage-
ment technology for developing countries in the tropics.
Primary funding is provided by the U.S. Agency for International Development through
Grant DAN 1311-G-SS-1083-00. This action is in support of Title XII "Famine Prevention and
Freedom from Hunger" of the Foreign Assistance Act.
The formal collaborators in the program are:
Agency for International Development-USA
Center for Soils Research-Indonesia
Cornell University-USA
Empresa Brasileira de Pesquisa Agropecuaria-Brazil
Institute National de Recherches Agronomiques du Niger-Niger
Institute d'Economie Rural-Mali
Institute Nactional de Investigacion y Promocion Agraria-Peru
International Crops Research Institute for the Semi-arid Tropics-India
North Carolina State University-USA
Texas A&M University-USA
University of Hawaii-USA

The Cover
Nowhere is the dependence of people on soil more critical or apparent today than in Africa's
Sahel, where drought, land degradation and population growth have brought famine and
hunger to millions. In view of this crisis, we present a Nigerien woman and a Sahelian land-
scape in this composite photograph. But in developing nations throughout the tropics, this link
of people to soil is no less real, the research no less vital.

TropSoils, the first three years was written and designed by Neil Caudle, Department of Agri-
cultural Communications, North Carolina State University. Production was by Paragraphics,
Zones maps and diagram, page 42, by Anne Marshall Runyon. Photos by: Neil Caudle, cover,
pp. 6, 7, 8, 10, 11, 12, 14 (left), 15, 16, 18, 19, 20, 21, 22 (right), 23, 24, 40, 43; Frank Calhoun,
p. 14 bottom; Walter Bowen, p. 22 (left); Pedro Sanchez, pp. 26, 27, 28 (bottom), 29, 34, 36, 37
(left), 39, 44, 46 (right); James P. Blair (c) National Geographic Society, pp. 30, 31, 35; Herman
Lankford, p. 33; Larry Szott, p. 38; Jot Smyth, p. 41 (top); Carol Colfer, pp. 46 (left), 47, 49, 50,
51, 53; Mike Wade, p. 52.
Copies of this report, and a companion book, ropSoils Triennial Technical Report, can be ob-
tained from TropSoils, Box 7113 Williams Hall, North Carolina State University, Raleigh, N.C.

Earth. One name for two things:
the planet we share, the soils at our feet. Both are in danger. We look
around the world and find ourselves needy, angry, starving. The dusts
of Africa descend on us all.
In the tropics, our good land is crowded, there isn't enough. We are
leaving the riverbanks, coming down from the mountains, up from the
coasts. We sew the dry edges of deserts with grain. We torch the stiff
brush of savannas so cattle can graze. We slash at the jungle, raise a
scant crop in its ash, and move on.
These are the thin lands, the parched lands, the acid, infertile and
erodable lands, where we're planting with sticks and stooping to weed.
There is no easy wealth in these lands. Still we must have them,
millions more hectares each year. There are so many more of us eating
scarce food, wearing scarce fibre, burning scarce firewood and dung.
We consume what has rooted in soils.
And now that we're staking our futures on these marginal lands, what
next? Can they sustain us? Can we both use and conserve them? What
must we learn?

"prevent famine and establish
freedom from hunger"
This is the heart of Title XII of the
United States Foreign Assistance Act. Title
XII recognized the role of U.S. land grant
universities in the development of modern
agriculture, and provided for a new part-
nership in which universities would join
government in an effort to help poor na-
tions develop their agriculture and secure
their food supply. Title XII also recognized
that, in order to apply science to solving
food and nutrition problems, universities
would need long-term, dependable support
to develop strong programs in research,
institution-building and technological
Much of this work would focus on ways
to produce more food from plants and
animals. Because soil-related problems
often seriously constrain this productivity,
some of the new research must logically
focus on soils. And, since the greatest
human need, and the greatest potential
resource base from which to meet that
need, are found in the tropics, that was
where the soils research began.

TropSoils is one of the Collaborative
Research Support Programs (CRSPs)
created by the Board for International Food
and Agricultural Development (BIFAD) to
implement Title XII. Nearly two years in
the planning, TropSoils is an international
collaboration that links developing nations,
the U.S. Agency for International Develop-
ment, international research centers and
U.S. universities. The collaboration ensures
that partner nations have a stake in Trop-
Soils' research, that it meets their needs,
and that the program draws on the
broadest possible base of knowledge and
To keep this collaboration working
smoothly toward its goals, the program is
guided by four groups: the management
entity, established at North Carolina State
University to administer the overall pro-
gram; a board of directors, consisting of
one representative from each university
and collaborating nation; a technical com-
mittee, composed of the principal in-
vestigator from each U.S. university; and
an external-evaluation committee of three
scientists from organizations that are not
TropSoils participants.

TropSoils research is keyed to agro-ecological zones in the tropics

"agronomically, economically
and ecologically sound"

TropSoils' goal is to develop and adopt
soil-management technology that is
agronomically, economically and
ecologically sound for developing countries
in the tropics. Because it has been impossi-
ble to do this in every tropical nation or
region at once, the program has sought to
situate and develop its research projects in
a way that would make their results ap-
plicable over broad areas having similar
soils and environments.
These areas, or "agro-ecological zones,"
became the basic units of TropSoils'
organization. Each participating university
took a lead role in one of these zones:
Texas A&M University, with its exper-
tise in dry-land agriculture, was chosen to
lead the program in the semi-arid zone,
and began research at sites in two African
nations, Niger and Mali.
Cornell University, with a fine record
of research in Brazil's Cerrado region, took
the leadership role in the acid-savannas
zone, and began work near Brasilia. North
Carolina State University (NCSU), which
had also conducted extensive research in
the Cerrado, assumed a support role.
The humid tropics, because of their
vast area and potential, were assigned two
primary research sites, each with its own
lead university. NCSU, which had already
established a strong program of tropical
soils research in Peru since it began work-
ing there in the 1950s, took the lead there,
continued developing a research station at
Yurimaguas, and began work on a second
site near Manaus, Brazil. The University of

Hawaii, because of its strong standing in
tropical agriculture and a long record of ex-
perience in Asia, was the choice to lead a
new program based in the Sitiung
transmigration settlements of West
Sumatra, Indonesia. NCSU provides sup-
port, extending and testing some of its
findings from the work in Peru.
Several of these universities have
begun or have planned work in another
important zone, the steeplands, where hilly
or mountainous terrain makes erosion a
serious environmental and agronomic con-
cern. The steeplands zone, which overlaps
the other three zones, will certainly figure
in future collaborative research programs.

the first three years
TropSoils was formally initiated in
September, 1981, and the job of developing
agreements with governments and institu-
tions began. Now the teams are on-site, the
research moving ahead. It's a slow
business, equipping and fielding a team in
remote regions, bridging the cultures,
breaking new ground. But already there
are results, successes. Basic information is
accumulating about such things as soil
types, fertilizer responses and water re-
quirements. And at each site, in every
zone, scientists and cooperating farmers
are showing that simple, low-cost tech-
niques can improve soil fertility and pro-
ductivity and boost yields in many cases.
So the effort is well underway, not just to
cover more tropical soils with good crops,
but to make sure that the new technology
fits agronomically, ecologically and
economically the regions and peoples it
serves. That is the story of this report.

Semi-Arid Tropics

The tropics of Asia, Africa and Latin America
all have substantial areas of semi-arid lands,
with a dry season of six to nine months and
soils that are dry almost half the year. Shifting
cultivation, nomadic herding, livestock ranch- Niamey
ing and subsistence tillage share these regions,
which, under the pressure of expanding
populations, are facing severe problems with
drought, desertification, erosion, soil-crusting,
sand-storm damage and declining soil fertility.
Most of TropSoils' work in the semi-arid SEMI-ARID TROPICS/NIGER AND MALI
tropics is set in Africa in Niger, Mali, and
Cameroon but the research here will apply
throughout the semi-arid zone. The reports that
follow focus on the Sahel, that broad swath of
rolling, sandy lands just south of Africa's
Sahara. It is a region where crops, and the peo-
ple who grow them, exist on the narrowest of
margins. It is, in the words of researcher Bob
Chase, "life on the edge."

Primary Collaborators
National Institute of Agronomic Research for
Niger (INRAN); International Crops Research
Institute for the Semi-Arid Tropics (ICRISAT);
U.S. Agency for International Development;
Texas A&M University.

Principal Investigator
Frank G. Calhoun, soil scientist (pedology),
Texas A&M University.

Two faces of the Sahel: parched during droughts and dry seasons-

The Sahel

The Sahel. Here every part of life, even
the light itself, is colored by soil. Red dust
rises on the harmattan and through it
sunlight filters amber and diffused. It is
land on the verge of desert, dry soil
thirsting for rain, waiting for its yearly ra-
tion of a few hundred millimeters, which
will come in brief bursts sometime from
May through September. Each kilometer
north toward the desert, a millimeter less
will fall.
For centuries, these semi-arid lands fed
only wildlife and the animals of nomadic
herders. Agriculture was a practice for the
riverbanks and the somewhat moister
southern regions, where the Sahel gives
way to the Sudan.
The nomads still ride their camels across
the northern dunes and the windswept
valleys of ancient, vanished rivers, driving
their cattle and goats. But recently the
farmers have been pushing northward, out
to where the earth is mobile in the wind,
where great, rolling sand storms blast and
bury crops, and the dry months often out-
number the wet. April is a brown, parched
and hungry time, waiting for green. And
when the season turns at last, the rains

may fall too little or too late to sprout the
millet seed, or bring the heads to flower.
With the red dust swirling outside his
window, seeping in to cover his books, his
desk, his work, Mamadou Ouattara talks
about the land.
"Before, we had an equilibrium between
man and nature," he says. "The soils were
not fertile but we were able to manage
them. Now, with the population growing,
and the recent droughts, the farmers have
been expanding their fields. They have in-
creased their area so that when a crop fails
they won't be left with nothing. The tradi-
tional fallow has almost disappeared, the
fertility is decreasing, and the soils are
very weak, very subject to erosion, both
from water and wind. The level of produc-
tion is really quite low."
Eighty-seven percent of Niger's people
are farmers, working the land by hand,
with almost no fertilizers or irrigation. The
mean yield from Niger's millet lands -
400 kg per hectare is perhaps a fourth of
what it could be if such problems as soil
fertility, erosion and sand-storm damage
were solved. Big ifs.
For Ouattara and his fellow Nigeriens,
the crisis is here and now. More drought
could bring the country famine. To them
it's not enough to sit and wait and count on
food aid. They must find a way, not only to

-Green with millet after the rains. Thatched huts are granaries.

feed and sustain their society, but also to
reverse the degradation of their resources,
to stop the encroaching desert, to rebuild
the soils and shape a land that can feed its
In another office Moussa Saley points to
a huge chart fastened on his wall. It is a
chart of all the jobs that must be done, the
scientific skills that must be marshalled to
the task. For some of these jobs, Saley has
a leader, someone, like Ouattara, with the
training to begin a program, organize
research. These are boxed with solid lines.
For too many others, there is simply no
one qualified. These have dotted outlines.
Moussa Saley says that what he likes
about TropSoils is that it has brought to
Niger badly needed expertise, in a spirit of
collaboration. And even though the work is
just beginning, he sees progress, promise.
In short, TropSoils has allowed him to
draw a few more solid lines. He is glad for

Mamadou Ouattara, chief, Division of
Ecological Research, International In-
stitute of Agronomic Research for Niger
Moussa Saley, director general, Interna-
tional Institute of Agronomic Research
for Niger (INRAN)

Women pounding millet in village


farmers, theory help
tackle big differences
over small spaces

Spatial variability. It's a term applied to
the marked differences in crop yields over
relatively small areas of land, a
phenomenon that confounds farmers and
scientists all across the Sahel. On ex-
perimental plots, variability can mask the

Chase in uniformly treated plot
Chase in uniformly treated plot

effects of fertilizers or other treatments,
rendering the data almost meaningless.
While variations in topography, soil
types, storm damage and organic matter all
contribute to variability in crops, there
seems to be another, more problematic fac-
tor as well: history. In most cases, resear-
chers simply don't know how the land has
been treated.
Bob Chase decided to ask the farmers.
He was looking for their opinions about
the reasons for variability, matching their
responses to data gathered by sampling in
the farmers' fields. As expected, the
farmers had some excellent, though
sometimes mystical, insights into why
some soils produced better crops than
others. They have even developed their
own system of soil classification.
"Farmers identify God, manure, rainfall
and wind roughly in that order, as the
overriding factors in millet production,"
Chase says. Manure has been harder to
come by recently, especially for farmers
who have put more land into cultivation
farther away from the villages.
Chase found that, in general, the pattern
of yield on the farms in his study was as in
the table below.
Chase is continuing these studies at
ICRISAT's Center for Sahelian Research,
collecting samples and analyzing their
chemical and physical properties in an at-
tempt to define the factors that cause
variability in Sahelian soils.
In a companion project at the Texas

:c.., .all it blaickls6I'F" :: -"

to poor
Blown dunes Poor Needs twice the manure of the
or depressions upland-flatland soils
Micro-gullies None Sealed surfaces prevent use

Agricultural Research and Extension
Center in Lubbock, Robert Lascano and
Charles Wendt have been collaborating
with Leo Stoonsnijder of the Netherlands
on another approach to the variability
problem: geostatistics. Geostatistics, a
theory developed in the 1960s, can be ap-
plied to describe variability for each obser-
vation or location in the experiment.
Classical statistical methods can account
for variation within an experimental unit,
but cannot address the distribution of
those variations in space. In the field, it is
more important to know where to expect
drastic dips or peaks in yield than it is to
know how often to expect them.
It's a job more of algorithms than
agriculture. But when it's done, the results

will be of use not only in the battle against
variability, but also in such things as soil
characterization and fertilizer placement. It
may even help with some of those "over-
riding factors in millet production" at
least with the manure, the rain, and the

Bob Chase, soil scientist (physics), Texas
A&M University
Robert Lascano, soil scientist (physics),
Texas Agricultural Experiment Station
Charles Wendt, soil scientist (physics),
Texas Agricultural Experiment Station
Leo Stroonsnijder, soil scientist (physics),
Wageningen Agricultural University, the

Soil Survey

Sizing up the soil's capacity as a bank for nutrients and water is fundamental to im-
proving agriculture both at the research site and on the farm. A soil survey enables
scientists to evaluate differences in results when, for example, tests crops are grown
on varying soils. And such surveys are essential when the goal is to transfer methods
or technology from one site to another.
So when a team of TropSoils scientists led by Larry West finished a detailed soil
survey of ICRISAT's Center for Sahelian Research. it was a key step, not only for
research at the center, but also for future work across the Sahel.
The survey, which took about 15 man-weeks for the field work, mapped soil types
and their boundaries by first analyzing aerial photographs for patterns of landform
and vegetation, then checking and correcting the map with direct sampling. Lab work
established physical, chemical and mineralogical properties, and assessed fertility.
The soils are strikingly different from most semi-arid soils in the U.S. They are more
acid, and have properties that indicate they evolved under wetter conditions, that
there was a climatic reversal, and that they began eroding relatively recently in
geologic terms.
The soils are developed in sandy parent materials that blanket a previously eroded
laterite surface. They are dominantly red to yellowish-red and their texture is loamy
fine sand or fine sand. Infiltration rates are favorable for the deeper soils that cover
most of the center, but there is likely to be significant runoff during very heavy rains.
There is very little chemical buffering; aluminum is present in levels toxic to plants,
and soluble nutrients are easily leached.
A 66-page report, Soil Survey of the ICRISAT Sahelian Center, by L.T. West, L.P.
Wilding, J.K. Landeck and EG. Calhoun, is available from Frank Calhoun, Soil and
Crop Sciences Department, Texas A&M University, College Station, Texas.

-- >J]


The Sandfighter

rig from West Texas
helps save crops
at research station

To a Texan, it may look peculiar, strap-
ped to a donkey. After all, this rig the
sandfighter got its start ripping along
behind big, fast diesels on the dunes of
West Texas. In Africa, it goes at a plod.
But plodding or not, the sandfighter that
Bob Chase modified for animal power has

Donkey pulls sandfighter on test plot

shown that it can improve the survival
rates of young crops at ICRISAT's Sahelian
Research Center near Niamey, Niger.
"In some cases it has meant the dif-
ference between having a crop to study
and not having one," Chase says.
Used soon after a rain, the sandfighter's
tines dig the damp sand into shallow
depressions and small, tight clods. The
broken surface traps windblown sand and
reduces the damage to young crops, which
are susceptible to sand blast and burial.
Chase has fitted his experimental sand-
fighter so that it also punches holes for
seed and fertilizer all in one pass. Millet,
a staple in the semi-arid regions of Africa,
has figured in most of the tests.
Andre Batiano, who has been doing soil-
fertility studies at the Center, is one of the
researchers most familiar with the struggle
to stabilize soils on research plots.
"Last year we lost our main experiment
because of sand blast," Batiano says. "It is
very important to find a solution."
Chase's first series of experiments, in
1983, used a tractor-drawn sandfighter,
pulled at three speeds (5, 10 and 15
km/hr.). Clod and hole dimensions were
measured in randomly selected sites. At
the ICRISAT center, researchers have used
the sandfighter to control sand movement
over most of the open fields until each was
planted, with good results.
Findings from these experiments in-
dicated that, under conditions like those at
the center, the sandfighter should be
pulled more slowly than expected, possibly
because of the low percentage of clay in
Niger's sandy soils.
"At first we thought tractors would have
to be used to achieve the high speeds re-
quired for optimum results when sand-
fighters are used in Texas," Chase says.
"Fortunately, the slowest speed we tested
worked best, and that means animal trac-
tion will be practical. Tractors are still a
rarity here, and they're too expensive for
most farmers."
Another unexpected result of the tests

Chase and Batiano in the field Hard

may also prove important. Chase found
that sandfought fields showed no standing
water or evidence of runoff after a heavy
rain, while untreated fields nearby showed
both. Because of the critical need to en-
courage rainwater penetration into
Sahelian farm soils, Chase plans to
measure the sandfighter's effect on soil
moisture and rainfall redistribution in
future research. He is also exploring its use
in weed control.
So far the sandfighter has been used
primarily for experimental work. But
Nigerien and American experts are en-
thusiastic about the potential for its use on
Niger's beleaguered farms.
James Lowenthal says that USAID has
begun coordinating sandfighter work on
extension farms in the region. AID is also
looking for ways of engineering and
manufacturing the sandfighter locally for
use with animals.
"We have all the pieces in place to move
from research to on-farm utilization,"
Lowenthal says.

Bob Chase, soil scientist (physics), Texas
A&M University
Andre Batiano, soil chemist, International
Fertilizer Development Center
James Lowenthal, USAID Mission, Niger

winds dry soils, bury young plants in sand

can windbreaks
increase crop yields?

Far down the Majia Valley, great rows of
trees stand up to comb the wind, to break
its force and reclaim airborne soil. Since
the first 13 rows of neem trees
(Azadirachta indica) were planted there ten
years ago, 160 kilometers of the valley have
been crossed with windbreaks. It is one of
the Sahel's most ambitious conservation
And by several indications, the work a
joint venture of CARE International and
USAID, with help from Nigerien foresters
is already a success, although its
economic and social impacts are still being
evaluated. In the 100-meter spaces bet-
ween the double rows, millet yields have
risen 22 percent over yields outside the
breaks. The trees, for the most part, are
surviving. And local farmers, who have
found the soils damper and millet greener
between the breaks, are convinced that the
trees have somehow attracted more rain.
So when TropSoils researcher Naraine
Persaud arrived this year and began plan-
ning his work in the windbreaks, the ques-
tions wanting answers were concerned not
so much with how to make the windbreaks
work, but rather, how do they work
and why? What were the key relationships
continued next page

of wind velocity, soil moisture and millet
yields? Could the planting pattern be im-
proved? And, perhaps most importantly,
could the work be replicated in other
windswept valleys of the Sahel? Niger's
forest service wants to plant windbreaks in
other locations, but such projects are ex-
pensive and, without quantitative informa-
tion about their performance, risky.
The first step was to understand the
soils. Larry West made a pedological ex-
amination of the site, the results of which
Persaud is using to space plots along the
transects he is laying out both along and
across the rows. Persaud is measuring
wind-velocity profiles inside and outside
the windbreaks, and will analyze these
profiles using one-dimensional momentum
balance equations, in order to find what
factors control the effect of the rows of
trees on wind velocity. He will also at-
tempt to quantify the effect of the wind-
breaks on soil moisture storage and on the
yield of millet.
Persaud says that while the research
will have a strong practical application, not
only for the CARE/USAID project but for
future windbreak plantings across the
Sahel, he has also planned an approach
that he thinks will make a contribution to
methodology in this field. In place of the
traditional randomized-block technique for
measuring changes along the transects, Per-
saud will apply new techniques for ana-
lyzing interrupted space, a method he feels
will greatly improve the validity of the
According to Steve Dennison, a forest
economist in charge of evaluating the
windbreaks project for CARE: "Naraine's
study will capture what we call the
'ensemble variations' of the site. It will
allow us to tie in crop production, and to
look at water loss inside and outside the
A TropSoils study closely related to Per-
saud's work is underway at the Texas A&M
University Agricultural Research and Ex-

tension Center in Lubbock, Texas, where
Charles Wendt and Robert Lascano are
studying the influence of windbreaks on
water evaporation from bare soil. Their
work, which combines measurements of
temperature, weather variables, soil water
and evaporation with simulations
generated by a numerical model, is ex-
pected to expand the theoretical
understanding of a windbreak's effect on
soil moisture, an understanding essential to
the successful design of future windbreaks
in the semi-arid tropics.

Naraine Persaud, soil scientist (physics),
Texas A&M University
Larry West, soil scientist (classification),
Texas A&M University
Steve Dennison, forest economist, CARE
International Majia Valley Project
Charles Wendt, soil scientist (physics),
Texas Agricultural Experiment Station
Robert Lascano, soil scientist (physics)
Texas Agricultural Experiment Station

wilting crop may need
fertilizer, not water

It seems so obvious, watching sorghum
or millet wilt in the sun: dry weather's kill-
ing the crops. But across the southern
Sahel, scientists are contradicting the ob-
vious. They have found that, many times,
plants die of thirst even when there is
moisture enough in the soil. The real trou-
ble, they say, is nutrients.
Previous research in Mali has shown
that, when nutrients are deficient, water-
stressed plants don't use all the moisture
available to them in the soil. It has been
estimated that fertilizers could perhaps in-
crease production five-fold, with only nor-
mal rainfall. The threshold seems to fall
somewhere near the 300mm mark. Below
that amount of annual precipitation, water
appears to be the primary limit to crop
But in developing nations like Mali, the
solution is not as simple as prescribing a
bigger dose of phosphorus or nitrogen.
Cost is a factor, and so is availability.
Clearly, knowing more about the relation-
ship between plants; water-use and
nutrients in semi-arid soils would help soil-
managers decide how to make better use of
the fertilizers available, and thereby in-
crease food production.
To TropSoils researchers at Texas A&M,
who have seen the same connection bet-
ween infertility and water stress on the
Texas High Plains, it seemed a natural sub-
ject for international collaboration. Their
studies, just getting under way at the Cin-
zana Experiment Station in Mali and the
Texas A&M Agricultural Research and Ex-
tension Center in Lubbock, Texas, are
designed to benefit both regions.
At the site in Mali, Mamadou Simpara,
Mamadou Keita, Arthur Onken and
Charles Wendt will be testing a number of
soil-preparation techniques, including ridg-

ing, subsoiling and tied ridges (furrow
dikes), with nitrogen and phosphorus ap-
plications as indicated by soil tests. The
goal is to compare various combinations of
fertilization and soil preparation for their
effect on plants' water-use and on sorghum
In Lubbock, Onken, and Wendt will at-
tempt to establish several important prin-
ciples in the water/nutrients relationship:
Will fertilizer applied to a nutrient-
poor zone in the soil profile improve water-
use by plants in that zone?
Where in the soil should nutrients be
applied, and at what rates, to promote op-
timum water-use by plants?
Some breeding lines of plants grow
larger (produce more dry matter) than
others in nutrient-poor soils. Do these
varieties also use water more efficiently?
The team will also analyze phosphorus
reactions in soil samples from Mali and the
Texas High Plains, in order to improve the
basis for research transfer. The work is
also expected to mesh with water-use and
fertility studies underway at ICRISAT's
Center for Sahelian Research in Niger.
It's the kind of international effort that,
in the beginning, meets with a host of
logistical problems and delays. But it also
offers the promise of real advances in food
production on semi-arid soils the sort of
advances that will likely pay off not only
on the dry lands of Mali, but on the dry
lands of Texas as well.

Mamadou Simpara, soil scientist (physics),
Institute of Rural Economy, Mali
Mamadou Keita, soil scientist (pedology),
Institute of Rural Economy, Mali
Arthur Onken, soil scientist (fertility),
Texas Agricultural Experiment Station,
Lubbock, Texas
Charles Wendt, soil scientist (physics),
Texas Agricultural Experiment Station,
Lubbock, Texas

Tiger Bush,

Leopard Bush

From the air it is clear why people call
this landscape tiger bush, or leopard bush.
The Guesselbodi forest, like much of the
woodland of the semi-arid tropics of
Africa, has receded into stripes and spots
of scrub trees and brush surrounded by
crusted, barren ground.
While scientists are unsure what causes
the forest to recede in these two distinctive
patterns, one thing is clear: The forest has
decreased. After studying aerial
photographs, Eric Boudouresque, botanist
at the University of Niamey, has estimated
that 30 to 50 percent of the Guesselbodi
Forest's vegetation has disappeared in the
last 30 years.
The region's urgent need for fuel has
pressed woodcutters deeper into the
forests each year, hacking away with axes,
loading the wood onto donkey carts and
camels. The topsoil erodes; bare crusts
enlarge and harden; water runs off without
soaking into the soil. When seeds fall
there, they blow away. Nothing grows.
To foresters and officials, it has been one

of Niger's most pressing problems: how do
we regenerate the badly depleted forests
and reverse desertification? While standard
methods, using transplanted seedlings,
cultivation and fertilizer, are being tried on
a small scale, they are too expensive for
widespread use in Niger. The search is on
for more practical approaches.
Bob Chase may have found one. Chase
knew that when there was new growth in
the forest it usually began in patches of
fallen branches or brush, which trapped
seeds and windblown sand, and attracted
termites. Termites improve soils in the
tropics in some of the ways earthworms do
in temperate regions increasing soil
porosity and incorporating organic matter.
Chase set up a series of trials to test the
natural regeneration of forest vegetation on
bare, crusted soils. He laid out 20 plots,
half of them protected from grazing
animals by a fenced enclosure. On each
site he prepared plots with three
treatments: cultivation with a hoe to about
10 cm, cultivation plus a mulch of
branches, and branches alone. The
branches were the wastes of woodcutting
nearby. Chase also left a part of each site
bare, as a control.
In July of 1983, eight weeks after the

The Guesselbodi Forest of Niger

Chase and
mulched plot

A woodcutter on crusted soils in the Guesselbodi Forest

beginning of the rainy season, there was
new growth on each of the treated plots.
And soil moisture in the treated plots was
2.7 to 3.8 times higher than in the control.
The volunteer plant species included a
large number of tree seedlings and a
legume suitable for the grazing animals
that herders bring to the forest. Not sur-
prisingly, the combination of branches and
tillage performed best, with an average
vegetative cover of 96 percent by
But then, after the next dry season, there
was a surprising development. Vegetation
on the mulch-only plots began to catch up
with vegetation on those with both tillage
and branches, and the tillage-only plots
had lost their plants and formed new
crusts. Extensive termite activity in the
mulched plots created stable
"macropores," which have significantly in-
creased water movement into the soil.
These trends seemed to indicate that
mulching alone simple, practical and in-
expensive might be sufficient treatment
to promote natural reforestation.
Chase points out that his studies are only
beginning, and it is too early to predict
what the long-term success of mulching
and tillage techniques will be. Amounts of
rainfall and new plant growth vary widely
year-to-year in the Sahel, and studies have

shown that survival of young trees will de-
pend on their being protected from grazing
during the first few years of life. Chase
plans to prepare new trials each year,
while recording the progress of the plots
established earlier.
In the meantime the work offers hope
that, in semi-arid forests like Guesselbodi,
tomorrow's trees may emerge from the
wastes of today's harvest.

Bob Chase, soil scientist (physics), Texas
A&M University



So 6

>: 2



2 J6

u U
Control Mulch Tillage Both
with by Tillage
Branches Hand and Mulch
Average soil water content to 45 cm depth onJuly 7, and biomass
of annual plants on Oct. 7, 1983


60 S

20 m

Herders in search of forage in the Guesselbodi Forest

A Team Effort

With the threat of crop failure and hunger ever-present in the Sahel, why the em-
phasis on forestry? Maurice Tardieu puts it this way: "When you have millet in your
granaries, you also have to cook it." In Niger, wood is the primary fuel. Reforestation is
also important in the fight against desertification.
TropSoils' research in the Guesselbodi Forest is one part of a cooperative effort by the
International Crops Research Institute for the Semi-arid Tropics (ICRISAT), the National
Institute of Agronomic Research for Niger (INRAN), and also by the U.S. Agency for In-
ternational Development (USAID), which is backing forestry studies in the Sahel.
USAID's Forest Land Use Project has begun an inventory forest resources, set up data
banks and a library, established model sites for trying forest-management programs,
and is researching techniques for erosion control and "water harvesting" directing
runoff so as to irrigate plants. The project has also organized a cooperative of villagers
living near the forests, with the goal of training its membership to take over some of the
management of grazing, woodcutting and reforestation. The work stresses the use of
native species.
John Heermans says TropSoils is helping to fill a gap in the research portion of the
"We are working with Bob Chase to help create a research effort in natural forest
management," Heermans says. "He's supplying soil physics expertise where it's badly

Bob Chase, soil scientist (physics), Texas A&M University
Maurice Tardieu, regional director, International Crop Research Institute for the Semi-
arid Tropics
John Heermans, forester, Land Use Project

Acid Savannas

Acid savannas are found in the tropics of
Latin America, Africa and Asia. These vast,
tree-dotted regions are dry four to six months
of the year, with rainfall totals ranging from
1200 to 2000 milimeters.
The acid savannas offer great promise for the
expansion of agriculture in many developing
nations. Their soils, while nutrient-poor and
acid, are easily worked and potentially very
productive. Gone are the days when the world
could afford to leave its acid savannas to the
occasional grazing herd.
One of the world's great savanna regions -
the Cerrado of Brazil, has become an
agricultural frontier where, with the proper
management, farms are producing dramatic
results. The reports that follow examine Trop-
Soils' efforts to learn the principles of soil
management that will help put acid savannas
to good use around the world. They are set in
the Cerrado, a region that has proven to be, as
Elmar Wagner puts it, "an excellent laboratory
for studying soil constraints."

Primary Collaborators
The Brazilian Agricultural Research Enter-
prise (EMBRAPA) and its Cerrado Agricultural
Research Center (CPAC); Cornell University
(lead U.S. institution); North Carolina State
University (support U.S. institution).

Principal Investigator
Douglas J. Lathwell, soil scientist (fertility),
Cornell University.

Cerrado range,
twisted trees

The Cerrado

Flying toward Brasilia on an August
night, you will see the bright fires like tiny
hoops and crescents of flame, dotting the
dark land as far as the horizon. The people
are burning the Cerrado. At night, when
the air is cool and calm, and the coral
snakes are mostly idle, the people go out
on the savanna and set fire to the tough
brush, hoping that green shoots will spring
up in the ash and feed their cattle. They
have burned it this way for as long as
anyone remembers.
They have burned but few have plowed.
There are 112 million hectares of arable
land in these rolling savannas called Cer-
rado. And while Brazil has hungered for
food and agricultural exports, most of this
land has remained unused. The real prob-
lem was not climate or economics or
culture. It was soil. The soil was infertile
and acid, so saturated with aluminum that
it withered most crops. The native vegeta-
tion showed the stress of living here: low
shrubs and tough grasses; twisted, stunted
But for all its bad chemistry, the land is
physically sound. The soils are deep, well
drained. Their clay particles are bound by
iron into larger grains that behave almost
like sand so nicely structured that they

can often be worked the day after a hard
rain. The chemistry, scientists suspected,
could be corrected.
And even more importantly, this savanna
land is vast and available an economic
and agricultural frontier and Brazil has
needed it. Through the 1960s airplanes
shuttled in huge loads of beams and
girders, and a gleaming new capital,
Brasilia, rose in the heart of the Cerrado.
The government offered incentives to
farmers, and the farmers came.
Now, on new farms in the Federal
District around Brasilia, huge, irrigated
fields of potatoes, rice and soybeans are
greening the landscape. Improved pastures
have multiplied the numbers of cattle Cer-
rado land can feed. A great variety of cash
crops, including coffee, citrus and avocado,
are showing great promise. Edson Lobato,
technical director of the Cerrado
Agricultural Research Center (CPAC), sums
up the region's potential this way: "With
good management, we can grow almost
anything we can think of." Agriculture has
come to the Cerrado.

Amadeu Tsuno stands in the door of his
warehouse, with stacked bags of fertilizer
and drums of chemicals behind him, tell-
ing a story more and more familiar in
Brazil. He arrived in the Federal District
six years ago, with his wife, one tractor and

little else besides ambition. He came from
San Paulo, in the south, where his family,
Japanese immigrants, still runs a small
Today Tsuno farms 293 hectares, with
another 1000 hectares on the way into pro-
duction. He has planted 220 hectares of
potatoes, and they have paid him well.
Tsuno has several tractors, buildings, and
he hires 150 people from a village nearby
to help him harvest potatoes.
Tsuno's story is like those of many other
hard-working farmers who have come to
settle here from the south of Brazil. His
farm is about average; some are as large as
3,000 hectares. Brazil is becoming a power
in agriculture, with this great resource, the
Cerrado, barely tapped.
What made such gains possible? Fer-
tilizer and lime, which offset severe
phosphorus deficiencies and aluminum
toxicity. Government incentives. Farmers'
hard work. And, perhaps most importantly,
Elmar Wagner, who, during his tenure as
director of the CPAC, helped bring Trop-
Soils to Brazil, says that science has played
the critical role in opening the Cerrado.
"At the beginning of the Seventies, there
was no hope to think about crops on the
203 million hectares we call Cerrado,"
Wagner says. "But now, with improved
management, we're seeing excellent
results, and we've found that this region
will support much more than just this ex-
tensive grazing."
Much of the credit for these strides,
Wagner says, belongs to an international
collaboration a collaboration whose U.S.
representatives included scientists from
universities such as North Carolina State
and Cornell, with financial support from
the U.S. Agency for International Develop-
ment. The teams showed that while the
Cerrado soils require large initial doses of
phosphorus and lime, the residual effects
of these applications can sustain crops for
years the investment does pay off over
The collaboration has been so successful
that the Brazilian Agricultural Research
Enterprise (EMBRAPA), which created the
CPAC, continues to support it as a fun-
damental part of its programs to develop
the Cerrado.
But with this boom of agriculture in the
Cerrado, there are still serious problems.
The region's soils erode rapidly unless
properly covered or contained, and gullies

Amadeu Tsuno

several feet deep can appear in a single
season. The high cost of chemical fer-
tilizers puts them beyond the reach of
many small farmers. Rainfall is irregular.
Insects and disease attack crops. And,
while mechanization and high-input
agriculture are showing dramatic results
for now, there are already worries about its
long-term impact on the land.
So the research goes on, not only for the
sake of Brazil, but for the extensive regions
of acid savannas throughout the tropics.
And that's where TropSoils' role comes in.
The Cerrado region, with its base of soils
and agronomy data, its well-equipped
laboratories and skilled scientists and
technicians, offers the maximum of
research results for a minimum invest-
ment, under conditions that will encourage
the direct transfer of knowledge to other
acid savannas around the world.
"This is an excellent laboratory for
studying soil constraints," Wagner says,
"not only because of the variety of soils
and soil conditions, but also for the diversi-
ty of agriculture and the social and
economic variety."

Edson Lobato, technical director, Cerrado
Agricultural Research Center
Amadeu Tsuno, farmer
Elmar Wagner, Inter-American Institute for
Cooperation on Agriculture

Brazilian extension agents walking barley field

Reds and Yellows

Walking the Cerrado, the easiest way to
tell when the soils change is to watch the
termite mounds. When the soils are red,
the termite mounds are deep brick-red.
When the soils are red-yellow, the mounds
are golden amber.
They share common traits, these acid,
iron-rich clays. But their differences are
important, especially when it comes to
water. For some undiscovered reason,
some of the red-yellow soils are sometimes
wet, with seasonally high water tables.
This is both good and bad. On the minus
side, high water tables worsen compaction
and erosion problems, and have to be tilled
with care. On the plus side, high water
tables can supply moisture to the root zone
during drought. The biggest problem is
how to tell which areas are damp and
which aren't, before you plow.
Mapping such features usually means a
lot of digging and boring of holes, using
familiar tools of the soil scientist's trade,
the shovel and auger. But Ray Bryant and
Jamil Macedo are studying ways of using
another, very high-flown tool to do the job:
the satellite.
Bryant and Macedo are analyzing the
photo-like maps generated by remote-
sensing equipment on the LANDSAT
satellite, and correlating the vegetation pat-
terns the images show with data the team
collects on the ground. If they can develop
a method of accurately predicting areas
with high water tables from features on
the satellite images, the technique could
probably be adapted not only across the

: vast land, vast potential

Cerrado but in other regions as well.
But even if its images prove useful, the
satellite won't get the TropSoils team out of
the hole-digging business altogether. It is
still important to understand the mor-
phology, or soil features, in the wet areas,
and to determine such things as when the
water table rises and how it fluctuates.
In most clays, persistent dampness
shows up in gray mottles. But curiously,
the red-yellow soils of the Cerrado don't
show any of the classic signs of poor
drainage. Using data and sampling sites
from previous research by Walter Couto,
Bryant and Macedo extended the study
area and recorded the gradations of color,
or hues, in their excavation pits.
Their samples are still being analyzed,
but early indications are that color may yet
be the key to predicting areas of high
water tables. The team has found a shift in
hues with depth that seems to correspond
to fluctuations in the water table. And
there are even some clues to the origin of
the soils' yellow tint.
Studying the root zone in the sample
area, Bryant and Macedo found a coating
of reduced iron on the roots, perhaps
deposited there during wet periods. If the
iron coating oxidizes when the zone dries
out, the yellow geothite mineral formed by
the oxidation would probably mix with the
soil, gradually changing its color.

Ray Bryant, soil scientist (pedology), Cor-
nell University
Jamil Macedo, research assistant, Cornell
Walter Couto, soil scientist (management),

Termite mound


Of the three principal nutrients necessary to grow crops nitrogen, potassium and
phosphorus nitrogen is often the costliest and the first to disappear from the field. And,
partly because it alters and moves so rapidly in the soil, nitrogen can also be the most dif-
ficult nutrient to study and understand.
Drawing on a strong program of nitrogen studies underway at its New York campus,
Cornell University began its TopSoils work in Brazil with a number of studies into the
role of nitrogen in acid-savannas soils. The studies sought ways of measuring nitrogen in
the soil, tracing its movement, and following the transformation of organic nitrogen,
which is found in plants and animal manures, as it is mineralized to the inorganic
nitrogen available to crops. The team is also seeking a soil "test" for nitrogen. Much of
this work focuses on green manures, cover crops that not only help prevent erosion but
also manufacture nitrogen for succeeding food crops.

Green Manures
Green manures aren't new. Farmers have
known for ages that some cover crops, par-
ticularly the legumes, which fix nitrogen
from the air in their root nodules, can im-
prove the soil and supply great quantities
of nitrogen to succeeding food crops.
But chemical fertilizers fast, efficient,
and simpler to manage with machinery -
have largely replaced green manures on
the big farms of industrialized nations. It
was a matter of economics: green manures
tied up land, labor and capital with crops
that yielded little or no income. They came
to be known as a luxury few farms could
But the bloom may be coming back on
green manures. And part of the reason is
the serious scientific attention green
manures are getting in developing nations,
where chemical nitrogen is often extremely
expensive and where farming is not so
mechanized. Even in the U.S., green
manures and animal manures are attrac-
ting more notice.
Douglas Lathwell of Cornell University,
principal investigator in TropSoils' acid-
savannas program, says that TropSoils is
pulling together extensive research from
both New York and the savannas of Brazil
in order to develop a more basic
understanding of green manures and
nitrogen management.
"Farmers in New York make extensive
use of manure and legumes as sources of
nitrogen, and in fact these sources of
nitrogen are far more important than fer-
tilizer nitrogen on most farms," Lathwell
says. "The research program in New York
has evaluated the components of cropping
sequences and manure management. In

Brazil and other areas of the tropics, we
must develop cropping sequences and
evaluate the various sources of organic
Lathwell points out that many important
food crops take up great quantities of
nitrogen. Corn, for example, requires as
much as 250 kg of nitrogen per hectare,
about half of which winds up in the grain
and is carried out of the field. Lathwell
says that unless a farmer corrects the
nitrogen deficit with legumes, fertilizer or
both, succeeding crop yields will be low.
"Our aim is to furnish the input-output
relationships necessary for a rational
analysis of the role of organic nitrogen,"
Lathwell says. "We want to develop prac-
tical management and cropping sequences
in which organic nitrogen is a feasible
means to improve crop yields, possibly as a
supplement or substitute for fertilizer
Lathwell says the TropSoils projects are
attempting to determine several things: the
total nitrogen content of crop residues,
manures and green manures; the rate at
which these organic sources are miner-
alized into inorganic nitrogen during crop-
ping, and the residual effect of this
nitrogen over several crops. Another goal is
to match the pattern of mineralization to
continued next page

Team threshes and weighs legume before
returning it to test plots (above). Walter
Bowen and mucuna that survived dry
season (right).

the crop's demand, so that the nitrogen is
used and not lost.
Walter Bowen and Shaw Reid of Cornell
have begun studying methods for manag-
ing green-manure nitrogen, using a legume
called mucuna, common in the Cerrado
region of Brazil and in much of the tropics.
The work has only begun, but so far
mucuna appears to have several strengths
as a green manure, not the least of which
is its apparent tolerance of drought.
"The question is, could you harvest your
food crop in March (near the end of the
rainy season), plant mucuna, and have it
survive the dry season to feed the next
crop," Bowen says. "This year, even though
the dry season began early, the mucuna in
our test plots is still green. And the dry
season is almost over."
Bowen and Reid's work is a follow-up to
a study in New York, where Dave Bouldin,
Lathwell and J.K. Jallah found that another
common green manure, alfalfa, can supply
most if not all of the first succeeding corn
crop's nitrogen needs if the alfalfa is prop-
erly incorporated into the soil. The team
measured the mineralization of organic
nitrogen over five years of continuous corn
During the first cropping season, the
green manure sometimes provided even
more nitrogen than the corn could use. But
each succeeding corn crop received less
nitrogen from the alfalfa residues, and, by
the fourth year, the nitrogen supply was

almost exhausted. These results, along
with methods of analysis developed during
the study, will help researchers at the
CPAC and elsewhere in the tropics predict
the contribution of nitrogen by green
But because supplies of organic nitrogen
vary tremendously from field to field and
crop to crop, the TropSoils team has turned
considerable attention to the develop-
ment of a key tool in the management of
tropical soils: a reliable "soil test" for
Work at several U.S. research stations
has tackled various methods for testing soil
nitrogen, and the most promising of these
seems to be a technique of incubating in
the laboratory soil samples containing
organic nitrogen. Bouldin, Jorge Quintana,
Eric Stoner and Alert Suhet are using
samples from Bowen and Reid's work to
conduct such incubation studies in Brazil,
measuring the rates and amounts of
nitrogen mineralization and correlating the
measurements with those in the field.
If the method works, scientists will have
a way of quickly and effectively screening
various green manures and nitrogen-
management schemes. And, perhaps most
importantly, the technique could probably
be applied throughout the tropics.
Eric Stoner says that while the major
focus of such studies is nitrogen, cover
crops such as mucuna have more to offer
than nitrogen alone.

" 1I: ;

'Erosion is a serious problem on these
soils," Stoner says. "Green manures can
help control erosion and recycle nutrients
such as potassium, so that they aren't
leached out of the system."
Stoner points out that green manures
might also help relieve the compaction and
hardening of soils cultivated by heavy
machinery, since incorporating organic
matter tends to improve soil structure and
discourage the formation of the hardened
layers called pans.
Wenceslau Goedert, the CPAC's research
leader in the TropSoils acid-savannas pro-
gram, says that these physical problems
may be more important than researchers
first thought.
"It has been a general observation that
Cerrado soils have no problem with com-
paction," Goedert says. "But after four or
five years of cultivation we are finding that
there is some compaction a hardening."
But the big advantage of green manures
is still their ability to provide low-cost
nitrogen. Stoner says that the high price of
urea, the nitrogen fertilizer available to
Brazilian farmers, has made green manures
very appealing.
"Many places in Brazil where you have a
frost-free dry season, and where moisture
is the only limitation to growing green
manures, people are starting to use green
manures, especially the small farmers, who
are not going to go out and spend money
on urea."

Fertilizer Nitrogen
and Gypsum
While green manures may satisfy some
of the acid savannas' appetite for nitrogen,
fertilizer nitrogen is still considered
necessary to successful large-scale
agriculture in the Cerrado. And using it ef-
ficiently can mean the difference between
a crop that makes money and one that
One of the advantages of fertilizer
nitrogen is that it is readily available to
plants in a soluble form as soon as it is ap-
plied. Organic nitrogen must break down,
or mineralize, before a plant can use it.
But this solubility of fertilizer nitrogen is
a disadvantage too. Inorganic nitrogen is all
too rapidly leached from the root zone,
especially during heavy rains, and much of
the expensive nitrogen applied to fields
never gets used by a crop.

Jeff Wagenet and Elias de Freitas are at-
tempting to adapt and simplify a method
for predicting what will happen to fer-
tilizer nitrogen in Cerrado soils. The pro-
duct of their TropSoils study, a revised
numerical model designed to simulate
nitrogen movement under various condi-
tions, would take into account such things
as nitrogen movement, leaching rates,
nitrogen uptake by plants, and the transfor-
mation of nitrogen compounds.
The goal is to provide a model simple
and adaptable enough to help agriculture
devise guidelines for the management of
nitrogen over a wide range of conditions.
Another complication in the manage-
ment of nitrogen is that not all sources of
nitrogen fertilizer are equal. In Brazil, the
continued next page

y. i. .. .. .

~ -~.~ti

Geodert at soil pit: roots can go deep when
red soils' chemical problems are solved

Eric Stoner,
research plot

major source of fertilizer nitrogen is urea,
which, according to Wenceslau Goedert,
has one significant drawback.
"In Brazil, we are almost self-sufficient
in nitrogen. But the source is urea, and
urea does not contain sulfur, which is im-
portant to crops," Goedert says. "We are
trying to work with Brazilian industry to
improve urea with calcium sulfate gyp-
But while the gypsum is available, inex-
pensive and sulfur-rich, little is known
about its long-term effect on Cerrado soils.
Incorporating the results of studies by
Djalma de Souza and Dale Ritchey at the
CPAC, Wagenet and de Souza will study
the chemical changes in Cerrado soils after
gypsum is applied. As in the nitrogen-
management work, their goal is to develop
a model that could predict the fate of gyp-
sum amendments under a range of condi-
tions, on soils outside the study areas.

Douglas Lathwell, soil scientist (fertility),
Cornell University
Walter Bowen, research assistant (soil fer-
tility), Cerrados Agricultural Research
Center and Cornell University
Shaw Reid, soil scientist (management),
Cornell University
Dave Bouldin, soil scientist (fertility), Cor-
nell University
J. K. Jallah, research assistant, Cornell
Jorge Quintana, research assistant, Cornell
Eric Stoner, soil scientist (management),
Cerrados Agricultural Research Center
and Cornell University
Alert R. Suhet, coordinator, resource
utilization program, Cerrados
Agricultural Research Center
Wenceslau Goedert, research leader, Cer-
rados Agricultural Research Center
Jeff Wagenet, soil scientist (physics), Cor-
nell University
Elias de Freitas, soil scientist (physics),
Cerrados Agricultural Research Center
Djalma de Souza, soil scientist (manage-
ment), Cerrados Agricultural Research
Dale Ritchey, soil scientist (management),
Cerrados Agricultural Research Center

x 3u~


Humid Tropics

Tropical America, Africa and Asia all have
humid regions, where rainfall is abundant at
least 1500 milimeters a year and there is a
temperature difference of only a few degrees
between the warmest and coolest months. On
the humid tropics' more fertile and accessible
lands, civilizations have risen and fallen for
thousands of years. But on the highly
weathered, acid and infertile soils of the vast
rain forests, farming and settling are still a
tenuous business. Agriculture, if it exists there
at all, is likely of the variety called shifting
Today, as crowding and hunger drive people
into these forests to clear and plant new fields
and pastures, there is worldwide alarm over
vanishing forests, and the fact that they are
sometimes replaced by eroding and badly used
soils. And while the myth of the rain forests'
role as the "lungs of the world" has been ex-
posed they consume almost as much oxygen
as they produce the threat to wildlife, to
new sources of germplasm, medicines and syn-
thetics, to the myriad and awesome wonders
the forests hold, are real.
There is no doubt that man will need land in
the humid tropics to raise his food. The task is
to choose that land wisely, use it well, and cut
no more than we must. Because of the size and
importance of this job, TropSoils has two
prominent programs underway in the humid
tropics, one based in Peru with a secondary site
in Brazil, the other based in Indonesia.
Together they are striving to put together soil-
management programs that not only will pro-
duce more food, but further the stewardship of
tropical forests and lands.

Primary Collaborators, Peru
National Agricultural Research and Exten-
sion Institute (INIPA); U.S. Agency for Interna-
tional Development (USAID/Lima); North
Carolina State University (NCSU).

Primary Collaborators, Brazil
Brazilian Agricultural Research Enterprise
(EMBRAPA); Rockefeller Foundation; NCSU.

Principal Investigators,
Peru and Brazil
Pedro Sanchez, soil scientist, NCSU, and John
Nicholaides, soil scientist, NCSU.

The Amazon drains a varied expanse of humid tropics, from river valleys-
r-l A .

Sne Amazon

The conventional wisdom ran something
like this: You cannot farm the soils of the
humid tropics. They are poor and infertile.
When you clear the jungle and break the
land, the soil turns to laterite, or brick.
So in the early 1970s, when North
Carolina State University (NCSU) began
testing ways of farming the soils of the
Peruvian Amazon, a lot of people thought
the whole idea was, well, quixotic.
But in the humid tropics, nations were
running out of room for people and crops
on the most desirable soils. Fertile ground
was not available ground. Hunger for new
croplands was pushing more and more
people into the rain forests, where they
would slash and burn a swatch of jungle,
exhaust the soil with one or two crops, and
move on to clear again.
Not that this slashing and burning was so
bad in itself. Shifting cultivation had for
ages been the earth's dominant agriculture.
As long as there was plenty of jungle, and
not too many farmers, the jungle had plen-
ty of time to restore itself, and the soil. It
was a sociable system, too, based on the
notion of choba-choba, or "You help me, I
help you." Neighbors pitched in to clear a
field. The women brought food. And later,
there was often a party, with plenty of
chuchuhuasi, a drink distilled from sugar
cane and tree barks.

But increasingly, in those bands of jungle
accessible by rivers or roads, there were
too many people. The fallow between
crops was cut short. Sometimes people
cleared the land with bulldozers, stripping
the topsoil, compacting the land so badly
the jungle wouldn't return. For better or
worse, people were using jungle lands to
grow food crops and graze their animals,
and their governments, pressed to provide
new food, new commerce, new oppor-
tunities, were showing the way. But the
cleared land was often too steep or badly
managed; there was erosion and neglect.
Too many tropical rain forests were being
wasted. In 1982, a study by two United
Nations agencies estimated that 7.5 million
hectares of tropical forests were being cut
each year; other estimates have been even
And wasting a rain forest was no small
thing. Two-thirds of the world's species of
plants and animals live only in the humid
tropics, and the great majority have not
even been described by science. Many of
our medicines and much of the germplasm
for new plants and materials come from
tropical rain forests, which have been
called nature's library of experience.
To scientists from NCSU, who had been
working with Peru to improve its rice pro-
duction on the coast, it seemed like a good
time to move into the jungle, to test the
conventional wisdom.

-to slopes and mountains, where erosion threatens cleared soils

They began with the soils. To anyone
who'd walked a farm in eastern North
Carolina, the resemblance was remarkable.
Same sandy loam surface, same red clay
subsoil. Same acid infertility. In fact, these
soils might have been found everywhere in
the coastal plain of the southeastern U.S.,
where agriculture was the foundation of
many a state's economy. The only real dif-
ferences were related to latitude and
climate: the land was warm all year, and
Some of the NCSU team felt, in the prob-
lems of the tropics, echoes of their own
state's history. Stan Buol did a little digging
in the library.
In 1822, a Professor Mitchell stood
before the North Carolina Agriculture
Society to condemn a practice that wasted
both land and the great eastern forests. He
described how generations of American
farmers had cut down the forests, quickly
exhausted the land's native fertility a
fertility built by centuries of decaying
leaves and trees and then moved on to
clear another forest, abandon yet another
barren field.
"This process," Mitchell said, "has been
going on till most of the tracts whose situa-
tion and soil were most favorable to
agriculture, have been converted into old
fields, and in our search after fresh ground
to open, we are driven to such inferior
ridge-land as our ancestors would have

passed by as not worth cultivating."
Professor Mitchell's solution? Manure.
Fertilize the land, he said, and you can
cultivate your best farmlands continuously,
and leave the poor lands and steep slopes
to the trees. Across the southeastern U.S.,
just such a philosophy has made the soils
- which Mitchell acknowledged were of
"middling quality" more productive
than ever before.
In 1971, NCSU and several Peruvian
agencies, with financial support from the
U.S. Agency for International Develop-
ment, began the Tropical Soils Research
Program in Yurimaguas, Peru, to determine
whether continuous cultivation of food
crops would be possible in the acid, infer-
tile soils of the Amazon Basin. Scientists
from NCSU, and Carlos Valverde of Peru's
continued next page

Woman with produce in a Peruvian market

National Agricultural Research and Exten-
sion Institute (INIPA), reasoned that if the
acid, infertile soils of the southeastern U.S.
could be cropped year-in, year-out, then
perhaps so could similar soils in the
They were right. In the May 1982 issue
of Science, Pedro Sanchez, Dale Bandy,
Hugo Villachica and John Nicholaides
reported that, after 21 consecutive crops
from a field first planted in 1972, a rotation
of rice, corn and soybeans produced an
average of 7.8 tons of grain per hectare per
year. The key was a careful program of fer-
tilizers and lime, which offset the soil's
nutrient deficiency and its high levels of
aluminum, and improved its cation ex-
change capacity its ability to retain
nutrients. Unfertilized fields yielded no
grain after the third crop. But after a
decade of continuous cropping, soil fertili-
ty in the fields with adequate fertilization
didn't decrease. It improved. And, contrary
to the many people's expectations, the soils
didn't turn to laterite or brick.
The authors concluded: "We believe that
the continuous cropping technology can
have a positive ecological impact where it
is practiced appropriately, because for
every hectare that is cleared and put into
such production, many hectares of forest
may be spared from the shifting
cultivator's ax... ."
But the team warned against rushing
large tracts into continuous cultivation, for
several reasons. While the technology
worked well on level or gently sloping land
(of which there are some 207 million hec-
tares of well-drained soils in the Amazon
Basin), continuous cropping on slopes

1902 photo of shifting cultivation in the
Appalachian Mountains of the U.S. (left),
and a recent view of the same practice in
the Peruvian Amazon

might bring erosion. Insects, weeds and
plant diseases, controlled through the rota-
tion of crops during the studies, would
probably step up their attack as the
technology became more widespread, and
it would be necessary to select pest-
resistant varieties of crops and use controls
Just as important was the danger of en-
couraging the clearing and planting of vast
areas with crops for which there was no
market, or no ready access to a market -
an ever-present problem in the remote
regions of Peru. And, before continuous
cultivation would work in the humid
tropics, it would have to suit the farmers,
bankers and buyers it would have to
find its place in the social and economic
structure of each region.
As Stan Buol puts it: "I haven't found a
farmer yet who will go to the trouble to
grow an extra cassava root, and send it off
to market, if he knows it won't sell."
And, the research team said, it would be
disaster to clear and plant huge fields, if
farmers had neither the know-how nor the
capital to manage them. Crop varieties and
rotations, fertilization schemes, pest con-
trols all must be tested and adapted to
the conditions in each farming area.
Careful soil testing would help determine
which lands could support food crops and
which would be better planted in trees or
What was needed was a middle ground
a bridge between the shifting cultivation
of yesterday and the high-input, con-
tinuous cultivation foreseen for tomorrow.
And that's where much of TropSoils' effort
in the humid tropics has been applied -
building that bridge.

Stan Buol, soil scientist (pedology), North
Carolina State University
Carlos Valverde, soil scientist, formerly of
National Agricultural Research and Ex-
tension Institute (INIPA); now at Interna-
tional Services for National Agricultural
Research (ISNAR), Netherlands
Pedro Sanchez, soil scientist (management),
North Carolina State University
Dale Bandy, soil scientist (management),
North Carolina State University
Hugo Villachica, soil scientist (manage-
ment), National Agrarian University, La
Molina, Peru
John Nicholaides, soil scientist (fertility),
North Carolina State University

Paddy Rice

new farms spring up
from research in Peru

In 1979, it was jungle. Now there's a church, a bar with cold beer, and a thriving
frontier community that takes its name from a hero of Peru, Tupac Amaru. Like
Amaru, who led a rebellion against the Spanish, these pioneers are doing something
revolutionary, but not with weapons. With rice. They are growing paddy rice where it
hadn't been grown before, except on research plots: in the Amazon Basin.
They came from the Andes, at first only a few families, looking for work. Some
found jobs on the research station at Yurimaguas, where they planted rice in research
plots Dale Bandy had laid out on fertile, alluvial soil by the Shanusi River, learning the
techniques. Soon they crossed the river with some seed, began planting rice of their
own. It grew.
"They are getting darn good yields," says Pedro Sanchez. "The farmers are growing
two and a half crops a year five crops over two years and averaging five tons of
rice per hectare a year. Now there are thirty or forty families, each with twenty or
thirty hectares."
Sanchez says this new rice industry, which sprung spontaneously from the research
at Yurimaguas, underscores the potential of rice in the Amazon, and also says a lot
about the eagerness of many Peruvians to adapt new technologies and improve their
standard of living. He points out that most of Peru's rice has in the past been grown on
scarce and dry coastal lands, which are costly to irrigate. On the rich soils along the
Amazon's rivers, rice grows well with little or no fertilizer.
"This puts rice where ecologically it belongs," Sanchez says, "and would allow you
to plant high-value crops on the coast."
Sanchez says that the collaborative research at Yurimaguas has been undertaken
with the view that soil-management was important not only for the acid, infertile soils,
but for the fertile, alluvial soils as well for the entire humid-tropics landscape.
Researchers at Yurimaguas cut and burned riverside jungle, leveled the site and con-
structed the dikes, paddies and water-distribution systems. Then, in a series of paddy-
rice studies, Bandy, Jose Benites and Luis Arevalo selected varieties, tested tillage and
planting methods, developed weed-control techniques, and matched rice plants' nutri-
tion requirements with soil fertility.
The result was a set of recommendations for managing paddy rice on the Amazon's
alluvial soils, recommendations Peru's farmers and extension workers have quickly
put to use.
"This year, Peru was self-sufficient in rice for the first time in many years," Sanchez
says, "largely because of the expansion of flooded-rice agriculture into the Amazon."

Dale Bandy, soil scientist (management), North Carolina State University
Pedro Sanchez, soil scientist (management), North Carolina State University
Jose Benites, soil scientist (technology transfer), North Carolina State University, based
at Yurimaguas
Luis Arevalo, soil scientist (chemistry), North Carolina State University

New fields,
Tupac Amaru


keeping yields up,
costs down

Modern agriculture in developed nations
is based largely on what has become
known as "high-input" technology:
mechanized cultivation and large quan-
tities of lime and fertilizer are used to over-
come the soil's limitations and produce
good yields. But in developing nations,
where capital is scarce, markets are
ephemeral, and fields are commonly small
S and tended by hand, high-input agriculture
very often won't work.
For this reason, a substantial part of
TropSoils' research in the humid tropics of
Peru has been aimed at developing "low-
input" technology that might improve
yields and conserve soils without demand-
ing huge capital investments or a drastic
break with tradition. At the Yurimaguas
Experiment Station, collaborating scientists
' from NCSU and INIPA began a series of
experiments aimed at testing various low-
input techniques in a field cleared by slash
and burn:
SResearchers selected cultivars of such

Carrying palm leaves to thatch a roof:
where farmers travel by foot and weed by
hand, low-input agriculture fits local
economies. (c) National Geographic Society

crops as upland rice and cowpeas -
developed and supplied by the Interna-
tional Institute of Tropical Agriculture
(IITA) that combined good yields with
tolerance to pests, diseases and high levels
of aluminum (see related story, page 32).
Many of these cultivars are now being
tested by INIPA.
Experiments with three tillage
treatments no-till, minimum tillage with
a hoe, and rotovation with a tractor -
showed that planting no-till and recycling
crop residues produced good yields of rice
and cowpeas, required low fertilizer in-
puts, gave excellent weed control, and
helped prevent erosion. The no-till system
offered another advantage over mechanical
cultivation: a farmer wouldn't have to
remove the tree stumps, which could sim-
ply rot in place. Techniques gleaned from
this work are being introduced to farmers
through Peru's extension service.
In another study using both no-till and
rotovation, the research team tested a crop-
ping rotation of acid-tolerant upland rice
and cowpeas, and compared the crops'
responses to several phophorus fertilizers.
The results showed that rock phosphate
performed very favorably compared to
costlier forms of phosphorus, perhaps
because the soil's natural acidity helped
make more of the phosphorus in the rock
available to plants. Again, the no-till ap-
proach produced results at least as good as
the results on rotovated plots.
New experiments focused on such
problems as weed-control, and on methods
of improving the downward movement of

.r-- -

Peanuts (mani) in early trials at
Yurimaguas: High-input cropping succeed-
ed, and the next step was to find a middle
ground-"low-input." (c) National
Geographic Society

calcium and magnesium in the soils, to off-
set subsoil acidity and promote root
In 1982, Jose Benites and Marco Nurena
combined many of these techniques into a
central experiment conducted under on-
farm conditions. The results were promis-
ing. Starting with a field freshly slashed
and burned from secondary forest, the
team used no-till, returned crop residues
to the soil, spaced plants carefully, con-
trolled weeds with herbicides, and applied
very small rates of fertilizers. The field
produced a total of 10.3 tons of rice and 2.1
tons of cowpeas per hectare during the
first two years. The rice yields were about
five times what the typical farmer's crop
produces without inputs.
"We have found that this low-input
system will produce good yields for the
first few years, while the stumps rot,"
Benites says. "It's a practical alternative to
the high-input approach."
But the researchers say it is possible that
low-input systems may prove to be
unstable after the first few years, and
might need to be treated as a transition to
other systems high-input cultivation,
agroforestry or pastures. Another possi-
bility may be to alternate low-input crop-
ping with two or three years of managed

Benites believes that when this low-input
"package" is thoroughly tested, it will have
a broad appeal to farmers in Peru and
elsewhere in the humid tropics: "It will
give them good results with a low invest-
ment and little risk."

Jose Benites, soil scientist (technology
transfer), North Carolina State Universi-
ty, based at Yurimaguas
Marco Nurena, agronomist, National
Agricultural Research and Extension In-
stitute (INIPA)

'Unknown African'

new method ranks
aluminum tolerance
of crop cultivars

It's called Africano Desconocido, the
Unknown African. And across the Amazon
Basin, this mysterious rice is taking root
and thriving. It grows chest-high -
farmers don't have to stoop to cut the
heads. It won't blow over as easily as other
tall varieties. It resists disease. And, it can
triple the yields of the native species.
But the most remarkable thing about the
Unknown Afridan is that it does all this in
acid soils soils very high in aluminum -
without demanding lime.
"Upland, we can get three tons of rice
per hectare, even under acid conditions,"
says John Nicholaides, who has been stu-
dying aluminum-tolerance in this and
other crop species. "For the native variety,
the average upland yield has been one
Nicholaides says that Melvyn Piha, now
at the University of California at Davis,
found and named the Unknown African
while working with TropSoils projects in
Yurimaguas. There Piha "rogued" the line
from a test variety whose seeds produced a
few atypical plants that grew well on acid

Tolerant, Tolerant,
Low Yield High Yield
Potential Potential
Sensitive Sensitive
Low Yield High Yield
Potential Potential

While it will take more research to deter-
mine if the African should be classed as a
true variety, and to assess its market poten-
tial, its credentials don't seem to matter
much to the farmers and scientists who
are using it successfully all over the
Amazon Basin.
"It has a lot of appeal," Nicholaides says.
"Extension and research people from
southern Peru came to workshops at
Yurimaguas and took the seed away with
them. We've had requests for seed from
Brazil, Indonesia and Sierra Leone, and
from a number of research organizations."
Ground limestone, the material common-
ly used to neutralize acidity and
aluminum, is expensive and hard to
transport in much of the humid tropics,
where aluminum toxicity in plants has
been called the number-one constraint to
crop production. Many farmers simply
can't afford to lime their fields. High levels
of aluminum in the soil stunt the plant's
growth, restrict its roots, and reduce its
tolerance to drought and disease.
Nicholaides says the TropSoils research
has been influenced by field trials with
farmers around Yurimaguas, who, despite
their willingness to adopt new seed types
and fertilizers, have been very reluctant to
invest in lime.
"It's an important part of our work not
just to modify the soil to the crop, but also
to fit the crop to the soil to evaluate
species and cultivars for their ability to
adapt," Nicholaides says.

Melvyn Piha (Above) with Unknown
African, the taller rice on his left. (Left)
Piha and Nicholaides' method for rating
cultivars' aluminum tolerance and yield

78% Al Saturation
- pH 4.0

. 0


9 60
_ 40 -

20 .

I. ,' I I I I I I
0 0.5 1.0 1.5 2.0 2.5 3.0 3.5
Yield on Acid Soil (tons/hectare)


Nicholaides and Piha have developed a
technique for evaluating cultivars for
aluminum tolerance and yield potential
under stress. In addition to rice cultivars,
the team has tested cowpeas, peanuts,
sweet potatoes, soybeans, and winged
beans, with encouraging results for rice
and cowpeas. INIPA is using the technique
to test rice varieties from all over the
world. And the work is showing promise,
not only for agriculture in the tropics, but
for crops on acid soils in the U.S. as well.
"For all practical purposes, the soils
we're working with in Peru are the same as
those on the Coastal Plain of North
Carolina," Nicholaides says. This similarity
enables the cultivar-testing to go on year-
round, an advantage to investigators like
Lisa Katz, whose work with Nicholaides
showed aluminum tolerance to be a domi-
nant trait in peanuts.
"When we planted the peanuts in
Yurimaguas, it was winter here,"
Nicholaides says. "If we had had to wait
for the growing season in North Carolina,
we'd have lost six months."
Nicholaides says that while the goal of
the TropSoils research is to develop
aluminum-tolerant crops that can be used
to increase food production and help
reduce hunger in developing nations in the
tropics, other regions stand to gain as well.
"In North Carolina, farmers are in many
cases not applying the lime the soils re-

quire. Some are leasing land year-to-year,
and don't know which fields they'll lease
until it is too late for a lime application to
do much good. Also, they are hesitant to
make the capital investment one that
will be good for several years on land
that doesn't belong to them."
Nicholaides says that aluminum-tolerant
cultivars, when they are developed, could
give such farmers better yields at lower
costs. Experiments have shown that, using
aluminum-tolerant plants, some farmers
could get by with less than one-half ton of
lime per hectare (about two and one-half
acres), applied once every three years.
"Without a doubt, this work will have
some application here in North Carolina,"
Nicholaides says. "It's a good example of
how international collaboration helps each

John Nicholaides, soil scientist (fertility),
North Carolina State University
Melvyn Piha, soil scientist (fertility),
formerly of North Carolina State Univer-
sity; now at the University of California
at Davis
Lisa Katz, former research assistant (soil
fertility), North Carolina State Universi-
ty; now a soil scientist on a kibbutz in


soils research
improves forage crops,
boosts weight gains

Across the Amazon, pastures seeded in
the ash of burned forests thrive for a year
or two, exhaust the soil's fertility, then
grow very thin. Often the grasses are badly
adapted. Cattle overgraze them. Erosion
begins. More forests fall.
It's a serious problem, not only in Peru,
but throughout the Amazon and elsewhere
in the humid tropics: a great many hec-
tares feeding too few animals. And the
animals are valuable, integral to most of
the Amazon's farming systems. People de-
pend on their Brahma cattle for both milk
and beef.
To the TropSoils team at Yurimaguas, the
need for better pastures was clear,
especially since much of the region's ter-
rain hills and acid soils might be bet-
ter managed as grazing land. But the
constraints were just as obvious: Farmers
could not afford to spend much money on
lime and fertilizers. The forage plants must
persist despite heavy grazing, insects,
disease and such soil-related problems as
acidity and low fertility.

grams/animal/day (four year average)

Unimproved Pastures


Cattle on improved pastures: important for
both milk and meat in the tropics
Using forage varieties developed by the
International Center for Tropical
Agriculture (CIAT), Pedro Sanchez, Dale
Bandy, Miguel Ara, Rodolfo Shaus, Ken-
neth Reategui and staff from several Peru-
vian institutions developed a broad
program of pastures research based at
Yurimaguas. The team tested and selected
the best-adapted CIAT varieties of acid-
tolerant grasses and legumes, studied their
persistence under grazing, and measured
the weight gains of animals grazing them.
"The pasture project has provided very
positive results," Sanchez says. "After three
years of grazing trials, we have a stable
pasture, and live weight gains six to eight
times greater than with native pastures,
with only minimal fertilization. Even
under heavy grazing pressure, there is
complete soil cover, eliminating the risk of
Soil tests showed that, with small ap-
plications of fertilizer, soil fertility general-
ly improved in the managed pastures,
especially in the topsoil, where the dense
network of roots and the effective cycling
of nutrients probably helped prevent
nutrients from being leached away.

Live weight gains of cattle on improved




Pastures performed well when they were
alternately grazed and left idle for 42-day
periods, allowing grasses and legumes time
to recover. But when the cattle grazed a
pasture continuously, a problem arose:
legumes began taking over the pasture, ap-
parently because the grasses were more
palatable to the cattle than were the
legumes, some of which contained concen-
trations of tannins.
Sanchez points out that in other
ecosystems, the value of legumes is mainly
as forage during the dry season, when
grasses stop growing. New studies under-
way at Yurimaguas are designed to find
what role legumes should serve in the
Amazon, where grasses are green year-
round. The researchers also want to know
how much nigrogen the legumes transfer
to the grasses. Meanwhile, Miguel Ayarza
has established studies in NCSU's
phytotron a lab specially equipped to
simulate the plant's environment to in-
vestigate the relationship between
nutrients in plants and their forage quality
for animals.
While some questions remain about the
best mixes of forage plants, the project has
demonstrated that better pastures are
possible in the humid tropics. And in Peru,
these findings are already having an im-
pact. Extension specialists have studied the
techniques and are testing them at new
locations across Peru. Demonstrations have
impressed Peruvian officials with the
potential productivity of well-managed
pastures. The results are being shared with
other countries through the International
Center for Tropical Agriculture (CIAT).
And most importantly, the research results
suggest that, with some know-how and
relatively low-cost inputs, the declining
quality of pastures in the humid tropics
can be reversed.

Pedro Sanchez, soil scientist (management),
North Carolina State University
Dale Bandy, soil scientist (management),
North Carolina State University
Miguel Ayarza, research assistant (pasture
management) North Carolina State
University, based in Yurimaguas
Miguel Ara, research assistant (pasture
management) North Carolina State
University, based in Pucallpa, Peru
Kenneth Reategui, animal nutritionist,
North Carolina State University, based in
Puerto Bermudez, Peru
Rodolfo Shaus, soil scientist, National
Agrarian University, La Molena, Peru

Pedro Sanchez. (c) National Geographic Society

tillage improves
compacted soils
In the humid tropics, great swaths of
cleared land are abandoned, eroding and
infertile, and much of the blame has been
laid squarely on the broad blade and wide
tracks of the bulldozer. Some Indonesian
transmigrant farmers, unable to raise crops
on land bulldozers had stripped of topsoil,
have preferred to clear new land by hand,
rather than risk more damage (see story,
page 47).
But while the drawbacks of mechanical
land-clearing have been plain to many,
there was until recently little hard infor-
mation about the effects of bulldozers on
tropical soils, or about how damaged lands
might be reclaimed.

Clearing by slash and burn

Work begun in 1972 at Yurimaguas,
Peru, by Chris Seubert and Pedro Sanchez
showed that land-clearing with a
bulldozer, used in place of the native slash-
and-burn method, seriously damaged the
soils' chemical and physical properties.
During a two-year period following clear-
ing, crop yields on bulldozed soils were
only 33 percent of those on soils cleared by
cutting and burning when no fertilizer was
applied, and 80 percent when the test plots
were adequately fertilized.
Sanchez says that negative effects of
bulldozing were caused by a combination
of soil compaction, the stripping of topsoil,
and the loss of nutrients stored in the
cleared vegetation. He adds that the native
slash-and-burn method returns some of
these nutrients to the soil as ash, does not
cause as much compaction, and leaves the
topsoil in place.
"After two years of continuous cropping,
crop yields on the bulldozed land became
so poor that it was abandoned," Sanchez
says. No secondary forest developed during
the six years following abandonment.
In 1980, eight years after the original
clearing, Julio Alegre and Keith Cassel
began studies to evaluate ways of reclaim-
ing that land. They found distinct evidence
of compaction between 15 and 45 cm
below the surface, even eight years after
the bulldozing.
Alegre and Cassel found that while
tillage of the top 20 cm of soil greatly im-
proved crop yields, results were even bet-
ter when tillage was combined with
chisel-plowing to a depth of 35 cm. Cassel
says that chisel-plowing helped break up
compacted layers and increase the soil's
porosity, improving root development.
The team also compared several land-
clearing methods for their effects on soil
physical properties slash-and-burn,
bulldozing with a standard blade, and
bulldozing with a blade designed to shear
off trees at the stump, called the "KG
blade" after the initials of its developers.
On each cleared site, the team also tested a
number of soil-management techniques to
see what combinations of clearing and

Alegre in test plots compacted by
bulldozers. Plot at left was tilled before
planting; plot at right was not

tillage worked best.
None of the clearing methods was
faultless. While bulldozed plots showed the
greatest decline in soil physical properties,
even the plots cleared by slash-and-burn
had some compaction and decreases in
rainwater infiltration.
"During slash-and-burn, even though
there's no machinery, there are people
walking around, and trees falling, causing
compaction," Cassel says.
After five harvests, Cassel reports that
crop yields show the plots performing in
the following order: Slash-and-burn pro-
duces the best results. Second is a com-
bination of bulldozing with the KG blade,
burning of felled trees, and disking to
loosen the soil. Third best is bulldozing
with the common straight blade, followed
by chisel-plowing.
Peru's extension service has adopted
these recommendations and is encouraging
farmers in the Amazon to clear by slash-
and-burn whenever possible, or by use of
the KG blade when time and manpower
are short. Since mechanical land-clearing
will probably continue in some areas, the
research team has focused on ways to
minimize the damage in such operations.
"I believe that, based on our experience
in this study, it may be possible to do some

mechanical clearing followed either by
disking or some sort of subsoiling opera-
tion," Cassel says. "Now, if we remove a
lot of topsoil during that operation, then it
won't work we won't get good results."
Cassel stresses that the trouble with a
bulldozer is not so much the machine itself
but its misuse.
"The experience of the bulldozer
operator and the procedures he uses are
extremely important," he says. "Some
operators can clear a site with very
minimal damage. The soil's water content
is also important, because compaction is
worse with wet soil."
Julio Alegre explains that, in Peru, many
of the bulldozers clearing farm fields have
been operated by people trained only in
road-building. "There is a lot of machinery
working on roads. The farmer rents this
equipment and just says, 'Clear here.' The
operators are used to driving back and
forth until the site is clear, compacting the
soil. Compaction is good for a road, but not
for a farm field."
While the research results show that
food crops can be grown on fields cleared
mechanically, Cassel and Sanchez both em-
phasize the need for good soil management
after the clearing, especially with the large
tracts necessary to make using heavy
equipment economical.
"Mechanical land-clearing commits you
to covering large areas of ground with a
crop right away," Sanchez says. "In some
areas, land has eroded because farmers
could not afford to cover everything the
bulldozer cleared."

Chris Seubert, former research assistant
(soil fertility), North Carolina State
Pedro Sanchez, soil scientist (management),
North Carolina State University
Julio Alegre, research assistant (soil
physics), North Carolina State University
Keith Cassel, soil scientist (physics), North
Carolina State University


Most farmers working big fields with
heavy machinery don't want trees in the
way maybe just a windbreak here and
there, a shade tree or two for livestock.
There's not much call for a forester when
the business is corn or wheat or soybeans.
But when the farm field is a few acres
slashed and burned out of the Amazon
jungle, and the crop is worked my hand,
trees are part of the cycle of life the
fallow that restores the soil.
To Chuck Davey, a forester who admits
to taking some kidding for "trading his
hard hat for a straw hat," there is a natural
partnership between agriculture and
forestry. He says this partnership is
especially important in developing nations
in the tropics, where shifting cultivation is
the rule and many a food crop is sewn
around charred stumps, to be fed by the
ash from burned limbs and trunks.
Davey points as an example to the
Amazon Basin of Peru. "Traditionally, the
farmer would go in and knock the jungle
down and burn it," he says. "He would
grow one or two crops, usually rice, then
abandon the field. The jungle would take
over. It used to be, in the days when
population pressures weren't great, that it
might be twenty years before that field
was used again."
Increasing population and the press for
new cropland have gradually cut the fallow
short, Davey says. "When the fallow is as
short as four years, the soil is not

Alley-cropping experiment with Inga hedge,
mulch of leaves and cuttings

replenished, and the weed seeds haven't
The forest fallow restores soil fertility
both because tree roots mine nutrients
deep in the soil and recycle them to the
topsoil in the form of organic matter -
decaying leaf litter, branches, ash from
burned trunks. And, many jungle trees are
legumes, fixing nitrogen in the soil.
Another advantage of the forest fallow is
that it provides a natural control for pests
and crop diseases, which don't have time
to establish themselves in a field before the
next fallow begins. In the humid tropics,
where pests and diseases thrive, that's
Davey says that TropSoils' agroforestry
work is testing ways to manage this forest
fallow in a way that replenishes soil fertili-
ty more effectively. Meanwhile, the program
is also looking for new ways to help Peru
harvest more food and fuel from forests
and tree crops.

Enriched Fallows
Davey and Larry Szott have begun study-
ing simple, low-cost ways of improving the
jungle fallow. In one study, the team is
creating what it calls an "enriched
fallow" by scattering seeds of such trees as
the Inga in rice fields just before harvest.
The Inga, common in the region, grows
rapidly, and is a nitrogen-fixer. Sewn in the
rice crop, favored species would get a head
start on the rest of the jungle vegetation,
which, in an unmanaged fallow, would
typically include only a few nitrogen-fixers
per hectare. The team is monitoring
changes in soil properties in the enriched
fallows, comparing them to the soil-
building progression in natural fallows.
"It's a low-input approach," Davey says.
"We're not trying to keep the jungle out,
we're just trying to see if we can improve
the jungle's ability to rebuild the soil."
Davey says that while the techniques
may indeed improve the fallow, the fallow
period will probably still need to be at
least four years. "We don't think the fallow
period can be less than that," he says.
"But, with this kind of management, the
succeeding crop will probably be better."

Alley Cropping
Despite their advantages, jungle fallows
still leave at least 80 percent of the
available farmland in jungle, a practice that
may not survive the increasing pressure for

new cropland. One possible alternative,
known as alley cropping, simulates the ef-
fect of fallow without taking whole fields
out of production.
Davey says the technique works this
way: The farmer grows his crops in the
alleys between rows of woody vegetation.
As he works the crop he slashes branches
from the row of trees and bushes with his
machete, and spreads them in the field as a
mulch. This adds organic matter and
nutrients to the soil, and helps reduce soil
temperatures. If some of the woody plants
are nitrogen-fixing, they may also supply
some nitrogen to the crops nearby.
"Using this approach might mean a more
permanent agriculture, and a more stable
population," Davey says.
Alley cropping, though successful on
some fertile soils elsewhere in the tropics,
has not been extensively tested on the in-
fertile, acid soils of the humid tropics. In
their trials at Yurimaguas, the research
team has planted rows of bushes and trees,
using a series of spacings to see which
alley size works best. They are also testing
various combinations of fertilizers, food
crops and tree and bush species, while
monitoring the chemical and physical pro-
perties of the soil.
Like the managed fallows, alley-cropping
represents an "intermediate stage" bet-
ween shifting cultivation and high-input,
continuous cultivation.

Tree Crops
Davey says it's hard to interest Peruvians
around Yurimaguas, people who spend a
good deal of time hacking away at the
jungle, in the idea of planting or tending
trees for timber.
"You try and talk about trees to most of
these people, they're not interested,"
Davey said. "There's not a large market for
lumber and firewood, yet. But if you talk
about something like tree fruits or living
fences, they might pay attention."
Farmers have told Davey that fences
must be "horse high, bull strong and pig
tight" a tall order in the tropics, where a
fence post rots almost as soon as it's set in
the ground. Davey has been studying ways
to plant and maintain rows of trees, fence
posts that won't rot or need replacement.
But some of the most interesting
agroforestry at Yurimaguas may turn out to
be work with the peach palm, an Amazo-
nian tree Davey and Jorge Perez have been
studying. The peach palm, which produces

a fruit high in protein, vitamins and oils, is
valued in Peru, where most of the fruit is
gathered wild. Perez has collected seed
from 1000 trees and is testing them to see
if some specimens out-perform others.
Research is also underway to determine
the peach palm's fertilizer requirements.
The peach palm, an important cash crop
in Costa Rica, has adapted well to culture,
and could prove to be a profitable crop -
that is, if a small controversy can be
resolved. There are two main varieties of
the peach palm. One variety's trunk
bristles with long, sharp spines. The
other's trunk is smooth.
"Right now, there's an argument over
which is better, the ones with spines or the
ones without," Davey says. "It's much
easier for a farmer to pick fruit from the
spineless tree he doesn't get stuck. But
the rats and monkeys can also climb the
spineless trees and get the crop first."
Davey says that all these TropSoils
agroforestry projects managed fallows,
alley cropping, tree crops are aimed at a
pair of general goals: helping farmers grow
food, and helping reduce deforestation in
the Amazon Basin.
"This kind of agroforestry is intended for
developing countries where the trees can
be of use in the farming system," he says.

Chuck Davey, forestry scientist, North
Carolina State University
Larry Szott, research assistant (forest soils),
North Carolina State University
Jorge Perez, forester, National Agricultural
Research and Extension Institute (INIPA)



S-.- Diameter



-q LI

50 100

Peach palm,
with spines




5.0 E

2.5 0


Nitrogen (kg/hectare)

Response of 18-month-old peach palms to

A New Way of Sorting Soils

If you gather food in the woods and fields, you'll want to know a little something
about berries. Now, you might not have the time or inclination to learn all the tax-
onomic tidbits you would need in order to identify each and every berry by species.
Probably you only want to know how to tell which ones are edible, and which aren't.
If you farm in the tropics, you've got a similar problem with soils. You don't want to
know all the thousands of combinations of soil characteristics that comprise soil tax-
onomy. You only want to know where to plant your crops and what to feed them.
In 1973, Stan Buol and his colleagues in the Soil Science Department at NCSU pro-
posed a system of grouping soils, a system they thought might help scientists, exten-
sion workers and farmers plan and manage their fields. The system was called Fertility
Capability Classification FCC.
The idea of the FCC was to identify the physical, mineralogical and chemical pro-
perties in the upper part of the soil profile that were important to agriculture, and to
use them in classifying soils. Because the properties used to define a given group of
soils were limited, the FCC greatly reduced the number of soil types a planner must
consider in order to make an informed decision.
A computer program made the system even easier. Keying in lab data and answers
to simple questions about traits in a given field, the operator could quickly classify the
soil and get a run-down on, for example, its expected fertilizer requirements.
After years of testing and fine-tuning, the FCC is rapidly becoming an institution in
agronomic research in the tropics, and not only on TropSoils sites. Tests in Indonesia
showed that the FCC produced more useful groupings for agronomic purposes than
either traditional soil taxonomy or the local classification systems. Thailand has
evaluated its soil classification groups using the FCC. It is an official system in
Venezuela. Taiwan used the system to select research sites, and also showed how the
response of paddy rice to nitrogen fertilizer clearly varied from one FCC soil type to
another. An adaptation of the FCC to paddy-rice soils in the Philippines was suc-
cessful, leading to new tests in 14 Asian countries. Copies of the computer program
have been supplied to Malaysia and to The Peoples Republic of China. And, criteria
for salinity have enabled planners to evaluate land in California, using the system.
Buol says the FCC will be an important tool in applying new soil-management
technologies and in transferring research results from one region to another, around
the world. But he adds that no classification system replaces basic soil taxonomy, soil-
testing and research.
"Classification is not science," he says. "Classification follows science.'
Buol also says that no matter how useful the FCC proves to be, it will continue to
need updating and refinement.
"As long as technology keeps changing new cultivation and management practices
the job of classification is never done," he says. "As our use of the resource changes,
the way we describe or interpret that resource changes, too."

Stan Buol, soil scientist (pedology), North Carolina State University

"As our use of the resource changes,
the way we describe or interpret
that resource changes, too"
S.-Stan Buol


transplanted research
adapts to new locale

Deep in the Amazon of Brazil, on a flat
plateau shaded by great, broad-crowned
trees that form a canopy thirty meters
above the ground, men walk easily through
the open understory, carrying their
machetes. They build a buttress at the base
of a huge old tree and climb to the top of
what will be the stump, the point where
the trunk begins its long, straight reach for
the sky. The trunk is three meters thick.
Through the day, they hack away at the
tree, chips flying, until the trunk topples,
the branches crash down, and the sun
floods in through a gaping hole in the roof
of the forest.
In the state of Amazonas, people have
always lived near the water, dependent on
rivers for transportation and trade. Now,
with the riversides crowded, they are
pushing into the primary forests, cutting
and burning, clearing new land. The
government has looked into the future, has
seen that some of its vast forests must fall.
The forests have little commercial value,
they say. The people need commerce. Oil
palms and rubber trees will raise the stan-
dard of living, develop a needed resource.
But the government has also recognized
that, unless the cutting, clearing and plant-
ing are managed with care, the land may
be ruined, the resource squandered.
"The government sees the Amazon re-
gion as a kind of escape valve for Brazil,"
says Jot Smyth, a TropSoils researcher
based at EMBRAPA's (the Brazilian Agri-
cultural Research Enterprise) research sta-
tion at Manaus. "Brazil wants to know
about the soils and how to manage them,
to work out some solutions before the
pressure's on, before the problems arise.
That's the reason for the research center at
Manaus was a natural place to test the
results from research at Yurimaguas, Peru,
on a site in the humid tropics with distinct
differences in soils and climate. Both
geographically and morphologically, the
soils at Manaus represented something of a
middle ground between the iron-rich clays
(called Oxisols) of the Cerrado and the
loamy soils (often Ultisols) common in the
Amazon of Peru. The climate is also in-
termediate: Manaus has a few "dry"

Robust corn of alluvial soils at Manaus:
the exception, where much of the land is acid
and infertile

months with less rainfall than at Yuri-
maguas, yet lacks the strong dry season of
the Cerrado.
"Our work at Manaus is largely adapta-
tion," Smyth says. "We wanted to know
what in the Yurimaguas technology needed
to be modified for these conditions. For ex-
ample, we knew pretty well, from the
Yurimaguas work, more or less what ferti-
lizer inputs we'd need. What we didn't
know was how much and when the
amounts and times of applications are
Smyth and Joaquim Bastos have found
both similarities and differences between
the two sites. Phosphorus fertilizers are
often unnecessary at Yurimaguas until the
third crop after slash-and-burn. At Manaus,
a phosphorus application to the first crop
doubles yields, probably because the clays
there require much greater doses of ferti-
lizer to satisfy their phosphorus-fixing
capacity, though not as much as is required
for the Cerrados. On the other hand,
potassium fertilization is similar for both
Yurimaguas and Manaus.
Smyth says farming practices in the two
regions are similar, too, with one excep-
tion: "At Manaus they weed with hoes," he
says. "In Yurimaguas, the farmer squats
and cuts the weeds with his machete."
Some of the research is looking at ways
to intercrop corn, rice, cowpeas and other
food crops with young oil palms and rub-
ber trees, in order to receive some benefit
from the land during the years before the
plantations begin to produce income. This
is especially important in Amazonas,
continued next page

Smyth says, where half the food is im-
ported from outside the state.
While the Manaus extrapolation work
bridges the technologies developing for the
Cerrado and those for the humid tropics of
Peru, Smyth says it is also developing
knowledge that will be useful at the
"primary" research sites. He cites as an ex-
ample studies at Manaus that focus on
guarana. Guarana, a bush that produces a
coffee-like bean very rich in caffein, has
become an important cash crop in the
Brazilian Amazon. Its seeds are ground to
produce a national soft drink, also called
guarana, a drink so popular its supply can-
not meet demand.
But despite its importance as a cash crop,
the guarana crop and its growth habits
have been poorly understood. Smyth,
Bastos and Jose Correa have been studying
three promising clones of guarana, measur-

ing their response to fertilizers and describ-
ing what Smyth calls the "soil-plant
nutrition relationships." Results of the
studies, Smyth says, will be useful in
testing the guarana elsewhere in the humid
"It's not just a matter of taking informa-
tion from a primary site and applying it at
the extrapolation site," Smyth says. "Many
of the studies we're doing at Manaus will
support those in Indonesia and Peru. It's a
two-way street."

Jot Smyth, soil scientist (fertility), North
Carolina State University
Joaquim Bastos, crop scientist, Brazilian
Agricultural Research Enterprise
Joe Correa, crop scientist, Brazilian Agri-
cultural Research Enterprise

After years of research in Peru, collaborating scientists have tested and adopted a range of
soil-management options for the Amazon Basin landscape (from Sanchez)

Sticking With It

commitment pays off
for people, research

Julio Alegre was born in the mountains
of Peru, the son of a potato farmer who,
like so many others, left the mountains for
the capital city, Lima. Soon after this report
is published, if all goes as expected, he will
be Dr. Julio Alegre. He will have earned a
Ph.D. in soil science from NCSU.
Alegre is quick to say what this means to
him: "In Peru, we don't have enough peo-
ple trained at this level. If I can go back
and train, for example, six M.S. students,
then those six may train twenty B.S.
students, and those twenty may go out and
train a hundred farmers. It is important
that while we are doing this research, we
are also building something for the future."
With support from TropSoils and its
predecessor programs, Alegre spent four
years conducting soil-physics research (see
story on page 36), improving his English,
and pursuing his degree. In 1982, he came
to NCSU to complete his course work and
compile the results of his research. He says
that the research at Yurimaguas is vital,
not only for people like him, who are
directly involved, but for Peru as a whole.
"About half the population of Peru is
around Lima, on the coast," he says.
"There is crowding. Sometimes there is
drought. We need more room. In the
highlands, there are big problems. They
have erosion, and there are only a few
vallies suitable for production. Peru has
decided we must develop the jungle. There
is enough area, and rainfall all year.
Before, people were scared of the jungle; it
was taboo. Now they are beginning to
come. Initially it's hard for them, changing
their customs, learning to eat new foods.
"At first, production was very poor in
these new areas. We didn't have any
research. Now, we can recommend fer-
tilizers, plant densities very simple kinds
of management that farmers can use to
double their production."
Alegre feels strongly that such gains
would have been unlikely without col-
laboration, both among scientists of dif-
ferent nations, and among scientists and

"What these farmers feel is very impor-
tant. If scientists don't have any knowledge
of what the farmer feels, it's much more
difficult to succeed. It's not just a matter of
bringing in new technology. We need the
interchange of information."
Alegre points out that the success of the
work at Yurimaguas has come largely
because of the long-term commitment to
research there, a commitment that has
given Peru the basis for a solid program of
research and extension in the Amazon and
him the consistent support he needed to
complete his education.
Pedro Sanchez says that this continuity
of effort more than a decade of sus-
tained research has many such benefits.
"There are some very good technical
reasons for maintaining a long-term pro-
gram," he says. "The fact that we have
answered some of these basic questions
has allowed us to move now from 'what' to
'why.' We know, in many cases, what
works, but we need to know why, so that
we can better transfer these results to
other areas. And there is a lot of concern
about sustained food production. We want
to know if these systems will be stable
over the long term. The only way I know
to find out is to stay there and farm it for a
long time."
The continuity has helped the col-
laborative research program to earn
credibility in the country, and establish
continued next page

what Sanchez terms "a measure of con-
fidence" in the developing technology. He
says the program has been able to link suc-
cessfully with many agencies and research
networks and compound its effectiveness,
largely because of this credibility factor.
"The soil-management practices for the
humid tropics that we have developed in
Yurimaguas are being tested elsewhere, in
Sitiung (Indonesia), for example. So far
they have been found to be valid."
One measure of the worth of a col-
laborative research program is the degree
to which the partner nation supports, or
buys into, the program. Victor Palma
points out that Peru's contribution to the
program, through INIPA, has risen steadily.
"Peru is planning to invest over $800,000
dollars in the TropSoils program (over the
next five years). Under Peru's present
economic conditions, this is really an enor-
mous investment."
He summarizes the program's impact

The Yurimaguas research station has grown
steadily during the decade of collaboration
among Peruvian institutions, NCSU and
USAID, becoming one of Peru's best

this way: "TropSoils' soil-management
recommendations are being tested and put
into extension packages throughout the
Peruvian jungle. The TropSoils program is
the main database for this region. And,
since 1972, the program has helped INIPA
in establishing and equipping the research
at station Yurimaguas, perhaps the best in
the country, and a training center in
Yurimaguas for research and extension
workers in the Peruvian jungle. We con-
sider this project not only oriented to
Peru's agricultural development, but it is
also international in its objectives."

Julio Alegre, research assistant (soil
physics), North Carolina State University
Pedro Sanchez, soil scientist (management),
North Carolina State University
Victor Palma, chief, National Agricultural
Research and Extension Institute (INIPA)


Primary Collaborators, Indonesia
Agency for Agricultural Research and
Development (AARD) and its constituent
Center for Soils Research and Center for Food
Crops Research; USAID; University of Hawaii
and NCSU.

Principal Investigator, Indonesia
Goro Uehara, soil scientist, University of

The Settlements

From Java and Bali they've come by the
thousands, making new homes under a
blazing sun and the tin roofs of the Sitiung
transmigration settlements, set up on West
Sumatra by the Indonesian government.
Often their neighbors were strangers, of
different ethnic groups, speaking different
languages. The land was a stranger as well
- rolling, acid, and infertile.
But the people, most of whom had never
farmed land of their own, were pleased
with their plots, their allotments of seed
and fertilizer, their dirt-floored wooden
houses. Soon the trees were falling, the
land cleared and planted with rice,
cassava, peanuts and soybeans.
The rain, though it fell in abundance, fell
furiously and much of it ran off. Even in
the humid tropics, soils can be dry. Plants
wilted. Some crops failed. Slopes eroded.
Too much land was abandoned, barren.
Soon many farmers saw that bulldozers
were spoiling their new land, stripping the
topsoil, opening the slopes to erosion. But
when they tried to clear the forests other
ways with slash and burn the root
mat was so thick they often couldn't
cultivate with hoes, the method many had
used in Java.
To the Indonesian government and scien-
tists, and their U.S. collaborators in
research, the challenge was clear: Develop
better land-clearing methods that conserve
soil and prevent erosion. Find ways to
reclaim lands too eroded and infertile to
support crops. Fashion new cropping
systems suited to the soils, climate and
economy of the region. And, make sure

Javanese transmigrant couple (left) working
among roots and stumps of new land at Si-
tiung: a long way from the neatly terraced
and fertile fields of Java (above)

that these new methods and tools will be
ones the farmers can use, that they will
work not only in Sitiung but in other such
settlements as well in Kalimantan, in
Sulawesi and in other parts of Sumatra.
The first step was to build a team: In-
donesia committed 15 scientists and
technicians, vehicles, some offices and liv-
ing quarters, and funds. The University of
Hawaii and North Carolina State Universi-
ty assigned three senior scientists and two
graduate students, some support personnel
and equipment. The universities offered the
aid of campus-based scientists in the U.S.
The formal agreements between govern-
ments were signed, U.S. AID supplied
TropSoils support, and, in 1983, the work
got underway.
It was a new program, just breaking
ground. But it was one designed to fill an
immediate need, and its objectives were
clear. Gordon Tsuji puts it this way: "The
primary goal of the project is to uncover
principles that will enable resource-poor
farmers who cultivate the fragile and im-
poverished soils of the humid tropics to
adopt soil-management practices that will
increase family income and farm produc-
tivity and at the same time preserve land
quality for future generations."
The first steps? Test techniques that have
worked in Yurimaguas and Manaus, and
some new ones as well. Begin providing In-
donesia with facts it needs to strengthen its
soil-management and agricultural-
assistance programs. Get to know two of
Sumatra's most important resources: the
soils, and the people who use them.

Gordon Tsuji, project manager, University
of Hawaii

Life in Sitiung

Indonesia's transmigration program has
been intended to help relieve over-
crowding, especially on the island of Java,
while at the same time developing new
farmland in undeveloped areas such as
West Sumatra. But such mass relocations
are notoriously difficult, especially when
farmers must sink new roots into infertile,
unfamiliar soils.
It seemed to the TropSoils team that
work in the six settlements in the Sitiung
area of West Sumatra would be better if it
blended soil science with social science. So
when researchers from the University of
Hawaii and North Carolina State Universi-
ty arrived in the settlements, they included
Carol Colfer, an anthropologist.
Colfer, whose previous work included a
development-oriented study of shifting
cultivation on the island of Kalimantan,
says her role in the TropSoils work is to
help researchers tailor their soil-
management studies to the needs of the
settlers of Sitiung. But she's also looking
for ways to "sensitize" soil scientists to
social factors important to their work, not
only in Indonesia, but in other developing
nations as well.
A time-allocation study, conducted with
collaborating staff from the Indonesian
Center for Soil Research, used a randomiz-
ed schedule of visits to settlers' homes over
a year's time. The team collected data on
the division of labor by age and sex, and
on the frequency and seasonal variations
of such activities as rice cultivation, home
gardening, labor for wages and home in-
dustries. The data are being entered into a
computer, Colfer says, so that any re-
searcher can tap the data base.
"The team has already asked how often
people must search for grass for their cat-
tle and goats; how farm labor is divided
between the sexes; the incidence of off-
farm employment, and the monthly varia-
tion in the productive activities of adults."
Here is some of what Colfer and her
assistants learned about life in Situing:

The Settlements
The 100,000 hectare transmigration site
is home for some 10,000 transmigrant
families and 1500 indigenous families. The
first large group of settlers arrived in 1976,
and each family received a modest home,
1.25 hectares of land and a year's supply of

food, fuel, seed and fertilizer. Six areas
have been settled, all called Sitiung after a
nearby village of that name. Each major
settlement is designated by Roman
numeral, and is subdivided into blocks.
Families in the six Sitiung settlements
have been assigned small, dirt-floored,
wooden houses with two bedrooms, a kit-
chen and living room. The houses aren't
pretty, says Carol Colfer, but most of the
settlers are happy with them. "Most of
these people came from huts of woven
bamboo, which are very picturesque but
leak and have no status. They are for the
poorest of the poor."
"The vast majority are Muslim," Colfer
says, "but they're not particularly fussy.
They will eat pork, and the women aren't
as modest as some Muslims."
There are three primary ethnic groups in
the settlements, each with its own
Family Life
The day begins at 5 a.m. Women nurse
their babies, haul water from the well, and
continued next page

East Javanese children in Sitiung V, after a
performance in honor of their village's new

make a wafer of fermented soybeans. The
workday is broken for rest during the hot-
test part of the afternoon.
The settlers have been surprisingly open
to government birth-control programs, but
there are still a great many children in
most households.
"The men are in charge of the farm work
and the women are in charge of the
children, housework and cooking," Colfer
says. "But there's a good bit of overlap.
Men cook and care for children; women
farm; children help. Often we see kids of
seven or eight walking around with two-
year-olds strapped to their hips. Child care
is viewed as a community job. Children
have a lot of freedom."
Most households have at least one
member working outside the home. Some
women work as maids.
Role of Women
Colfer was surprised to find that women
took a lesser role than she expected in
agriculture and decision-making, and were
less involved in government-sponsored ex-
tension programs. She says such programs
could help women improve some of the ac-
tivities they are most involved in, such as
food-processing and marketing. And,
because women work very hard in home
gardens, Colfer sees a potential for them to
begin raising the same high-value crops re-
quiring intensive cultivation.
Diet and Income
Nutritionists interviewed people from 80
families in their homes, twice. Preliminary
results of the study include:
Incomes range from about $8 to $200 a

Nutrition was marginally adequate.
A lack of variety in the diet suggested
a possible cause of nutritional deficiencies.
The people ate virtually no meat.
The nutritionists conducting the survey
advised the research team not to concen-
trate on high-value crops: the people would
sell them rather than eat the better foods
Even so, most of the families felt better
off than before. "Some of them had had
lifestyles which involved simply scavaging,
wandering around with everything they
owned on their backs," Colfer says.
Skills and Education
"These are very low by Indonesian stan-
dards," Colfer says. "In one group of
seventy-five families, two people had
junior-high educations."
Most of the people had been working in
agriculture, but under vastly different con-
ditions of soils and climate. On the plus
side, Colfer says that most are very open to
learning about new agricultural methods.
"In working with these farmers we've
tried to emphasize that we're all ex-
perimenting together," Colfer says. "One
big problem for everyone is predicting
rainfall, and timing the planting with
regard to the beginning of the rainy season.
In Java, they were used to distinct seasons,
wet and dry. In Sitiung, there's never a
clear demarcation."
Information Exchange
The settlers live among strangers, and
speak several different languages, and yet
news about seed, crops and cultivation
somehow spreads through the settlements.
"It's informal," Colfer says. "Information

Research team in the field, from left to
right: Djoko Santoso, Mike Wade, John
Thompson, Carol Colfer and Karim

Settler in her kitchen

seems to travel through families and ethnic
groups through kinship channels. I was
surprised to find at Sitiung Five how much
new people talk to those who have been
there a long time. They find that different
areas have different strengths. Sitiung Four
is a source of seeds for rice and peanuts,
and Sitiungs One and Two have knowledge
about soils."
Indonesian extension agents are young
and energetic, Colfer says, and are pro-
viding useful information despite some
resistance from farmers, who sometimes
suspect them of "controlling" checking
up on transmigration violators.

"Javanese see rice as absolutely essential
- the base," Colfer says. "But rice doesn't
grow well here. Casava does, and there is a
factory nearby that buys cassava and
makes flour. But after transportation costs
and other expenses, you get about one and
a half cents per kilo, maybe less. So people
aren't jumping to grow cassava. Also, their
general perception is that cassava depletes
the soil."
The government is promoting soybeans,
and peanuts are planted as well. Indiginous
families have done well with tree crops,

but for settlers the problem is waiting for
tree crops to produce.

Ann Wade, a sociologist and wife of
Mike Wade, soil scientist from North
Carolina State University, conducted a
survey in Sitiung for the Small Ruminants
Collaborative Research Support Program.
The survey showed that a lot of settlers lik-
ed owning cattle, even though the cattle
were too valuable to eat. A good cow is
worth about $400. Settlers view them as a
source of milk and fertilizer, and as a kind
of insurance against hard times. A govern-
ment program entrusts the care of a cow to
a family. The family must give away the
first calf, but may keep the second. The
family spends about an hour a day gather-
ing grass for its cow.
"People also keep goats, but they save
them for parties," Colfer says.

For the most part, it's been good. Colfer
says there were some early problems
because people thought the researchers
were officials checking-up on them. "But
once they understood what we wanted,
they answered our questions quite readily,"
she says.
If anything, the settlers tried to be too
kind and helpful. "Sometimes they will say
what they think you want to hear, just to
be polite," Colfer says. "That's why, in In-
donesia, it's important to hang out a while,
observe, and listen to what they say to
each other."
Colfer says work with the farming
families has already had considerable in-
fluence on research design. Local farmers
suggested that the team replace a legume
grown to improve soils in one of the ex-
perimental cropping rotations with
mucuna. The farmers pointed out that
mucuna, which is also a legume, would
both improve the soil and provide a food.
"Throughout the process we have altered
things to make them acceptable to the
farmers without really negatively influenc-
ing the research," Colfer says.
Colfer has lived with farm families in
one of the settlements at Sitiung, doing
what she calls participant observation to
learn about such things as family life and
customs, work habits, information ex-
change and farming practices. These obser-
continued next page

Clearing logs from new field

vations, along with surveys and
experimental collaboration projects with
groups of farmers, have impressed her
with the settlers' ability to contribute to
soil-science activities.
She found that, even though many of the
transmigrants were accustomed to the fer-
tile, volcanic soils of Java, they have quick-
ly learned that their new land needs
special care. Most of the fertility lies in the
topsoil, and the subsoil is practically
sterile. In the beginning, poor land-clearing
practices led to severe erosion and some
areas were abandoned.
"The thing that has impressed me most
so far is the amount of knowledge people
seem to have about soil," Colfer says.
"They're worried about erosion. They're
aware of the importance of terracing; they
understand that bulldozers can be very bad
for the soil. In Sitiung Five, for example,
they had the opportunity to have
bulldozers free, to clear all those trees off
their land, and most of them would not
take it because they didn't want their land
ruined. They'd rather go through the ter-
ribly hard labor of clearing it by hand."
Colfer says she has been surprised by the
optimism with which the families view
their transmigration. Despite such prob-
lems as low incomes and marginal nutri-
tion, most of them, she's found, feel they
are better off than they were, largely
because they have been provided with land
and shelter. On Java, they typically had
tiny parcels of less than a hectare, or no
land at all.
"Their biggest complaint is that it's too
quiet here," she says. "There's a shortage
of singing and dancing."

Note on the research team
Carol Colfer has led TropSoils research
into social structure and farming systems
in the settlements, but she hasn't been
working alone. A large team of scientists
and assistants has contributed to the ef-
forts described on these pages. The team

Atin Kurdiana, field assistant, Center for Soil
Suwandi, field assistant, Center for Soil
Edi Santoso, field staff, Center for Soil
Heryadi, field staff, Center for Soil Research
Sarmi, junior high school student, Sitiung I
Veronica Kasmini, field assistant, Center for
Soil Research
Barbara Chapman, project director, Bogor
Street Foods Project
Liek Irianti, Institute Pertanian Bogor Nutri-
tion Department
Bartholomeus Wied, Institute Pertanian
Bogor Nutrition Department
Harry Apriadji, Institute Pertanian Bogor
Nutrition Department
Ann Wade, sociologist

Woman holds rice she harvested selectively
from her yard


Barren Land

Seeing the damage, it almost seems
hopeless. Topsoil stripped or eroded. A
hard, compacted surface. Bare subsoil, acid
and infertile, where not even cassava will
grow. Bulldozers, hasty clearing, poor ero-
sion control they've all contributed to
the degradation of large areas of land in
the settlement area.
Indonesia wants to stop the degradation
and reclaim abandoned land. It's a big job.
How does man go about rebuilding soils it
took nature ages to build?
The TropSoils team of Karim Makarim,
Keith Cassel, John Nicholaides, Mike Wade
and Gunawan set up an on-farm trials to
evaluate various chemical and physical
treatments for an unproductive hillside in
Sitiung II. In a cropping cycle of rice, soy-
beans and mung beans, the team tested
low and high rates of lime and fertilizers,
along with various tillage methods, against
a control.
While rice production improved from
almost nothing on the control plots to
moderate yields with the addition of lime
and fertilizers, the best results came when
green manures were added to the soil-
amendment recipe. After turning under a
legume cover crop, the team found
substantial gains in rice yields at all three
levels of fertility.
In fact, low rates of lime and fertilizers,
coupled with green manure, produced con-
siderably more rice than high fertilizer
rates without green manures 2.71 tons
per hectare vs. 2.15 tons. Adding organic
matter to the soil also improved the soil's
physical properties, though not as marked-
ly as with deep tillage. (For a related story
on green manures, see page 21.)
Unlike the rice, which yielded only
about 17 percent better with high fertiliza-
tion rates than with moderate rates, the
soybean crop tripled its yields with the
larger doses. The team found, also, that fer-
tilization increased the residual level of
phosphorus in the soil, and the heavy lim-
ing completely eliminated exchangeable
aluminum both factors in the increased
yields. These residual effects will benefit
succeeding crops.
While these food-crop tests continue,
John Thompson and D.S. Gunawan began
working on the land-reclamation problem
from a different angle: forage. As Carol

Bulldozed land in Sitiung

Colfer found in her time-allocation studies,
Sitiung families spend considerable time
every day cutting forage from roadsides
and abandoned fields for their animals.
The feed is poor, the time costly. The Trop-
Soils team, working in association with
scientists from the Center for International
Agriculture in the Tropics (CIAT) and the
Center for Soils Research, gathered and
tested a number of grasses and legumes to
see which would perform best on degraded
So far, four grasses and one legume show
promise as cover crops that can feed
livestock and reclaim eroded land, and
there will likely be more.
The results of these studies will help In-
donesia mend some of the damage to its
soils, not only in Sitiung, but in other
transmigration sites as well. And, as the
teams point out, the information will also
be welcome in the U.S., since it will shed
some light on the basic principles of
rebuilding a soil. The scientists are seeing
first-hand the soil-forming processes at
work under dynamic conditions perhaps
unknown in the U.S.

Karim McKarim, research assistant (soil
physics), North Carolina State University
Keith Cassel, soil scientist (physics), North
Carolina State University
John Nicholaides, soil scientist (fertility),
North Carolina State University
Mike Wade, soil scientist (fertility), North
Carolina State University
D.S. Gunawan, research assistant, Center
for Soil Research
John Thompson, agronomist, University of

Soils, Crops and


To hoe or not to hoe. To lime or not to
lime. To fertilize or not to fertilize. For the
transmigrant farmers of Sitiung, strangers
in a new land, finding answers isn't always
a simple matter of consulting a wise old
relative or neighbor. It's a new place, large-
ly unstudied, almost without agricultural
tradition. But a great deal rides on the
answers crops, incomes, food.

On-Farm Trials
The idea was for TropSoils projects to
answer basic questions about soils and
cropping systems, as quickly as possible,
taking some of their cues from the
farmers themselves. Mike Wade's team -
which included Carol Colfer, Djoko San-
toso, Suwandi, and Atin Kurdiana set up
on-farm trials with 19 farmers who took
charge of tillage, crop-protection and plan-
ting patterns. The scientists wanted to test
various combinations of fertilizers against
the government's recommendations. At the
same time, the team wanted to build a
working rapport with a group of Indone-
sian farmers a rapport that would
benefit both.
Intercropping relay-planted cassava with
rice and, after the rice harvest, with chili
peppers and peanuts, the researchers and
farmers found that tillage was a very im-
portant soil-management consideration.
Hoeing forest litter into land recently
cleared, but not burned, greatly improved

Cowpeas in research plots, simulating on-
farm conditions

yields on both fertilized and unfertilized
But there was one exception to this
trend: Liming a field increased yields and
almost offset the advantage of hoeing. This
was a point in favor of lime, since farmers
working newly cleared land quickly tire of
hammering away at the thick mat of tree
roots that lies just under the surface.
While these trials are likely to help scien-
tists formulate fertilizer and soil-
management recommendations, they also
benefit the research in other ways. Resear-
chers have a rare opportunity to monitor
soils and farming practices, beginning with
a first crop on new land. They have some
good, basic information to use in designing
new studies. And, they have laid a founda-
tion for more collaboration.

Liming is a relatively new practice in In-
donesia, and such questions as when,
where and how much to apply are
unanswered. What was clear was the need
for more research; the acid, red-yellow
soils of Sitiung were very similar to those
on many transmigration sites throughout
Indonesia, and what worked on one site
would likely work on others. Two TropSoils
projects began to sort things out.
In one of these projects, Wade, Agus
Sophian and Kasno began comparing two
sources of lime, burned lime and ground
lime, for their effectiveness in neutralizing
soil acidity and improving crop production.
Burned lime, which is made from ground
lime, is not considered economically feasi-
ble in developed countries, may be poten-
tially competitive in Indonesia as a home
or small-scale industry.
In initial trials, upland rice, which is
known to tolerate acid soils, showed
almost no response to lime. Peanuts show-
ed a slight response, and mung beans, a
crop sensitive to high levels of aluminum
found in acid soils, exhibited a very
definite response.
In a companion project, Wade, Gene
Kamprath, Djoko Santoso and Rumawan
are trying to determine what soil acidity
levels are optimum for upland rice, soy-
beans, peanuts, corn and mung beans.
They want to know what liming rates are
needed to maintain these levels, and the
residual effect of various rates on a rota-
tion of food crops. Early tests have shown
soybean yields climbing steadily as lime
was increased and soil acidity decreased.

About the Soils

Although the soils are deep and permeable, without physical barriers to root growth,
practically all of their fertility lies in a very shallow layer on the surface. Native
vegetation has accumulated most of the available plant nutrients into its biomass,
releasing them slowly as the vegetation dies and decomposes, directly feeding the
roots. Therefore, removing organic material from a site, by bulldozing, for example,
greatly reduces the site's fertility.
Under this surface layer of organic material, the soils, which are generally more
than half clay, are acid, with levels of aluminum toxic to plants. They are also nutrient-
poor, with a lack of weatherable minerals. Unless these chemical constraints are cor-
rected, cleared land will be barren. While there are some areas of relatively level land,
much of the transmigration site is rolling, with short, steep hills prone to erosion.

Both projects, which are continuing, will
help Indonesia's Center for Soil Research
develop a set of guidelines for lime applica-
tions that may be extended to areas with
similar soils.
It's a matter of the right dose for the
situation. Some soils need almost no
phosphorus. Others need large doses. But
as yet no accurate method for matching the
dose to the need is available for the set-
tlements. The need varies not only with
the soil but with the crop as well. The 100
kilograms-per-hectare allowed to Sitiung
farmers are fine for upland rice, but ap-
parently far too little for peanuts.
In another continuing project designed to
establish basic guidelines for the use of soil
amendments, Wade, Santoso and Suwandi
began studying rates, methods and long-
term effects of phosphorus applications
using triple super phosphate. The first test
crop, peanuts, showed a dramatic response
to phosphorus, and yields increased from
almost nothing to nearly a ton per hectare.
The project is continuing, but some early
results suggest that the government's
recommendation that phosphorus fertilizer
be banded laid in bands along the rows
adds unnecessary labor. In the TropSoils
trials, which were managed by researchers
in farmers' fields, simple broadcasting per-
formed as well as fertilizer banding, when
both applications were incorporated by
hoeing. If long-term studies confirm this
trend, a change in policy would benefit the

Mike Wade, soil scientist (fertility), North
Carolina State University

Carol Colfer, anthropologist, University of
Djoko Santoso, soil scientist (management),
Center for Soils Research
Suwandi, research assistant, Center for
Soils Research
Atin Kurdiana, research assistant, Center
for Soils Research
Agus Sophian, research assistant, Center
for Soils Research
Kasno, research assistant, Center for Soils
Gene Kamprath, soil scientist (fertility),
North Carolina State University
Rumawan, research assistant, Center for
Soils Research

Farmer hoeing a new field

Strips and Spots

sorting the puzzle
of spatial variability

Rolling, acid and variable, the soils of the
transmigration area of West Sumatra
challenge farmers and researchers alike.
One of the first tasks for the new TropSoils
team was to survey and assess the soils in
order to establish a baseline of information
for its studies. Another was to try and
understand spatial variability the
sometimes extreme differences in soil con-
ditions and crop responses over relatively
small areas.


*,, ,/M 2

". g/m2
",-~-"-* 300
-. 200

', ,- ,,, ... '.': c~~=

Why is the typical farm in Sitiung alter-
nately dotted with bare spots and striped
with green bands? TropSoils researchers
found that the bare spots were areas where
acid, sterile subsoil had been exposed by
bulldozers, and the green strips were
usually the ash lines of burned trees. Many
of the bare spots were abandoned by
farmers, and have rapidly eroded.
Accommodating such variation in a farm
field means carefully measuring and apply-
ing lime and fertilizers in differing rates to
suit conditions a hard job, even for
farmers who apply their chemicals by
hand. On research plots, where the goal is
to measure the effect of treatments under
reasonably uniform and replicable condi-
tions, variability greatly complicates
Like scientists from TropSoils' Semi-Arid
Tropics Program (see page 8), the Trop-
Soils team in Indonesia has looked to
geostatistics for help in analyzing variabili-
ty in soils, and its effect on crops. Using
geostatistics to estimate soil properties at
unsampled locations from analyses of
neighboring samples, the team, which in-
cludes Bruce Trangmar, Mike Wade, Djoko
Santoso, John Thompson and Russel Yost,
has shown that natural soil variability can
actually help research by revealing
answers to key agronomic questions. For
example, data from a variability trial show-
ed that differences of rice yields were
more related to aluminum (which can vary
from zero to 90 percent saturation on
freshly cleared land), potassium and
micronutrients than to such things as
organic matter, nitrogen and phosphorus.

Bruce Trangmar, research assistant (soil
physics) University of Hawaii
Mike Wade, soil scientist (fertility), North
Carolina State University
Djoko Santoso, site coordinator, Center for
Soil Research
John Thompson, agronomist, University of
Russell Yost, soil scientist (fertility),
University of Hawaii

Diagrams showing soil acidity-aluminum
saturation-(below) and grain yields (above)
on the same test plot

Wade in uniformly
treated test plot

Variability, Piece by Piece

It looked like a failure, a key experiment and a lot of hard work down the drain. The
object was to find the response of mung beans to phosphorus, but the test plot, a neat
rectangle, contained a wildly disorganized pattern of growth. Patches of mung beans
were thriving, others were hardly alive.
"Normally, when the micro-variability is that extreme, the tendency is to plow it
under and start over, somewhere else," says Mike Wade. "With that kind of variability,
you can't tell much about the crop's response."
But the experiment was crucial, and losing it would cost valuable time. Wade decid-
ed to call on some campus colleagues for help. Gene Kamprath and Russel Yost arrived
to study the plots and talk things over. The diagnostic approach they agreed on was
based on a time-honored scientific principle: examine the cause-and-effect.
"We came up with a plan:' Wade says. "We marked off any uniform spot in the
field, whether good or bad, and sampled it. We harvested and measured yield and
took soil samples one each plot, just as if it were a field in itself."
Jig-sawed by stakes and string, the field became a puzzle, each piece yielding a dif-
ferent set of data. Piece by piece, the puzzle came together, a picture formed the
relationship between growth and several soil characteristics.
"We found out that where there was poor growth the soil acidity was high:' Wade
says. "And where growth was good, soil acidity was low and the bases, calcium and
magnesium, were high. Looking at all these factors, we could explain the growth
Wade says that, because his team could draw on the expertise of soil scientists with
different backgrounds and experience, the program found a new way of dealing with
variability, and the experiment was salvaged.
"We actually used the variability to get more information than we'd expected," he

Mike Wade, soil scientist (fertility), North Carolina State University
Gene Kamprath, soil scientist (fertility), North Carolina State University
Russel Yost, soil scientist (fertility), University of Hawaii

In Conclusion

To prevent famine, alleviate hunger and meet the minimum dietary needs of its
population, the world must increase its production of food. This is an accepted fact.
The actions necessary to meet this challenge are clear: increase production on existing
fields, and bring new lands into the system. For either approach to succeed, the soil
constraints that limit plant growth must be minimized. The goal of TropSoils is to ad-
dress this issue. Formally defined, this goal is to develop and adapt improved soil
management technology which is agronomically, ecologically and economically sound
for developing countries in the tropics.
The level of success achieved in reaching this goal will be influenced by the
resources available and the effectiveness with which they are used. The TropSoils ap-
proach, collaboration, is designed to enhance both these factors.
Though the program is still in its infancy, identifiable progress has been made. The
program is already developing technological practices that have the potential for im-
proving food production in developing countries. Dedicated and capable people are
forming and conducting a unified program that is both technically sound and suited to
its goals. We are pleased to have had the opportunity to present some of their work.
Charles B. McCants
TropSoils Management Entity

Management Entity Office
Charles B. McCants, Director
North Carolina State University
Kim S. Stevens, Administrative Assistant
North Carolina State University
Neil Caudle, Editor
North Carolina State University

Board of Directors
Morris Bloodworth, Chairman (until 10/83)
Texas A & M University
Ada Demb, Chairman (after 10/83)
University of Hawaii
Wenceslau J. Goedert (after 7/84)
Brazilian Agricultural Research Enterprise
Mamadou Ouattara
National Institute of Agronomic Research
for Niger
Robert H. Miller
North Carolina State University
D. Muljadi (until 1/84)
Center for Soils Research
Edwin B. Oyer
Cornell University
Victor Palma
National Agricultural Research and
Extension Institute
E. C. A. Runge (after 10/83)
Texas A & M University
M. Sudjadi (after 1/84)
Center for Soils Research
Elmar Wagner (until 7/84)
Brazilian Agricultural Research Enterprise

Technical Committee
Frank G. Calhoun, Chairman
Texas A & M University

Douglas J. Lathwell
Cornell University
John J. Nicholaides
North Carolina State University
Pedro A. Sanchez
North Carolina State University
Goro Uehara
University of Hawaii

External Evaluation Panel
John Coulter, Chairman
World Bank
Peter Hildebrand
University of Florida
Marlowe Thorne
University of Illinois

Agency for International
John Malcolm, Program Manager
AID/Science and Technology
David Bathrick
Allen R. Hurdus
Adolfo Jurado
Howard Lusk (after 1/83)
S.K. Reddy
Samuel Taylor (until 12/82)
Wilbur Thomas (until 7/83)
Frederick Vigil (after 7/83)


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