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Title: Management of productive space in traditional farming
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Permanent Link: http://ufdc.ufl.edu/UF00091571/00001
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Title: Management of productive space in traditional farming
Physical Description: Book
Language: English
Creator: Wilken, Gene C.
Subject: Farming   ( lcsh )
Caribbean   ( lcsh )
Agriculture   ( lcsh )
Farm life   ( lcsh )
Farming   ( lcsh )
Spatial Coverage: South America -- Mexico -- Caribbean
South America -- Guatemala -- Caribbean
South America -- Belize -- Caribbean
South Ameirca -- Honduras -- Caribbean
South America -- El Salvador -- Caribbean
South America -- Nicarragua -- Caribbean
South America -- Costa Rica -- Caribbean
South America -- Panama -- Caribbean
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Bibliographic ID: UF00091571
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
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Table of Contents
    Front Cover
        Page 408
        Page 409
        Page 410
        Page 411
        Page 412
        Page 413
        Page 414
        Page 415
        Page 416
        Page 417
        Page 418
        Page 419
    Back Cover
        Page 421
Full Text




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The term management in the title of this paper suggests an orientation
and level of sophistication not usually associated with traditional or nonindus-
trial farming. But it is the thesis here that traditional farmers are skilled
professionals, with long experience in particular cultural-environmental situa-
tions, who have developed effective methods for managing agricultural resources.
From this perspective, traditional systems are not simply collections of pri-
mitive or anachronistic practices of little modern consequence, but instead
may represent attractive alternatives to high-energy industrial approaches
to farming. The following discussion concentrates on management of just
one resource, that of space, with examples drawn from various traditional
Middle American farming systems.
Geographic discussions of space in farming systems generally are limited to
locational aspects, to the problems presented by distances between places.
Analyses concentrate upon farm-market relationships and on-farm distributions
of crops, fields, and farmsteads with the aim of determining least-cost spatial
arrangements. This negative view, of space as an obstacle, applies especially
when the focus is upon transfers of inputs and outputs.
But from the perspective of production, space can be viewed as an agricultural
resource. Crop plants require certain amounts of horizontal and vertical
space below and above ground from which to extract moisture and nutrients,
intercept sunlight, and develop physically. Relationships between farm
space and productivity have not been ignored, as evidenced by the abundant
literature on such topics as optimum farm size, economies of scale, and pro-
ductivity per unit of horizontal area (e. g., hectare). But to consider space
as an agricultural resource subject to management provides new perspectives
and a basis for new analyses.
The concept of space as a resource must be placed within the context of tra-
ditional or small-scale farming. Typically small farmers have holdings of less
than five hectares, divided into several parcels. They have considerable
knowledge of plant requirements and some ability to alter energy and mois-
ture flows and environmental conditions to favor crop production. Farm inputs,


including energy and materials, come mainly from local sources. Operating
on such a small and tenuous scale, traditional farmers are sensitive to oppor-
tunities for using their few productive resources as completely and as often
as possible.
Like other resources, space becomes scarce when demand exceeds supply.
In traditional societies this often results from increasing populations. But
in addition to subsistence needs, demands for increased commercial or social
production may increase output requirements and thus farm space needs 2.
There are two general factors that can be manipulated : the plants themselves
and the environment. Crop plants and biological processes, however, remain
relatively fixed over the short run. Therefore, the process of intensification
essentially is one of extending greater and greater control or management over
various elements or resources of field ecosystems with the goal of increasing
output per unit of space. But increasing horizontal or vertical density of
productive biomass or use frequency of field space places a drain on other
resources such as soil or water. Thus farmers who actively manage produc-
tive farm space also must exercise considerable control over other agricultural


Maximum utilization of available space begins with general field layout and
configuration. The objective is to minimize non-planted spaces. At the
same time a certain amount of what might be termed field infrastructure is
necessary. Farmers must allow for access to plots by themselves, their power
and transport units, and for such inputs as irrigation water. As a rule, labor
saving equipment is space wasting. Thus large tractors and mechanized equip-
ment work well in ample, open fields but poorly where space is limited. In
contrast, the small tools and power units of traditional farming permit wor-
king even awkward field corners and edges. The ultimate in this regard is
hoe cultivation where there is hardly a piece of ground too small or remote to
escape cultivation.
Within technological limits, farmers view alternatives as a series of trade-
offs in which space is saved at the expense of some other resource or of human
energy. Most traditional systems compromise by using combinations of human,
animal, and powered equipment. Thus loads may be carried to field edges
by hand, then to farmsteads by animal-drawn carts or wagons or even by
trucks. Similarly, hand-scooped or splashed irrigation water usually is brought
alongside plots by gravity or pumps. Space management is costly in human
energy and most traditional systems strike a balance between scarce space
and arduous labor.
A common measure or productivity, output per unit of horizontal space
(e. g., tons per hectare), contains the unstated (and distinctly mid-latitude)
assumptions of monocultural practice and a single crop year. Comparative
agricultural censuses, if they do not ignore the issue entirely, must adjust for
mixed and phased cropping 8. Yet many traditional farming regions regularly


multiple crop and enjoy long to year-round growing seasons in which neither
temperature nor moisture, either from precipitation or irrigation, prohibit
crop production at any time. If space is at a premium, frequency of use achieves
the same objectives as intensity of use. Space management may include
techniques for decreasing the time a crop occupies field space as well as the
amount of space used per crop. In this sense, time and space can be equated.

Multiple Cropping.

Growing two or more crops in the same field at the same time is common
wherever traditional farmers need to maximize total output per unit of area.
Possible crop combinations are endless. The mix of maize and beans (NAhuatl
tlatlaoyo), for example, often accompanied by squash, has come to typify tra-
ditional garden-fields throughout Middle America. Part of the success of
this ancient system is because these plants do not compete for identical space.
Tall maize (Zea mays), medium stature climbing or shrub beans (both Phaseolus
vulgaris), and ground-hugging squash (Cucurbita spp.) may share the same
horizontal space but occupy different vertical levels where they find sufficient
room to develop. Other crops, such as chayote (Sechium edule), red and husk
tomatoes (Lycopersicum esculentum and Physalis spp.), quelite (Chenopodium
spp.), broad beans (Vicia faba), ayocote (Phaseolis coccineus), chick pea (Cicer
arietinum) or peas (Pisum sativum) often are found in temporal (rain-watered)
fields along with the maize-bean staples. Volunteer crops from the previous
season complicate deliberately planted mixes but by no means are precluded
from the harvest.
Where soil and water also are under careful management, multiple cropping
becomes more complex. Instead of two or three crops, a single plot may
contain as many as five or six, growing in rows at uniform intervals or in ran-
dom confusion. Nor is multiple cropping limited to subsistence plots. In the
Department (State) of Quezaltenango, Guatemala, for example, such commer-
cial crops as beets, cabbage, cauliflower, carrots, celery, coriander (cilantro;
Coriandrum sativum), lettuce, potatoes, radishes, and spinach are grown in
combinations designed to maximize production per unit of horizontal space
and to insure against loss should prices on any one crop be low at harvest time.
Those farmers with adequate land plant but one or two crops on each plot.
Those with little productive space will mix three, four, or more vegetables in
the same plot. Thus a farmer with three cuerdas (0.13 ha; one cuerda =
0.044 ha) might plant separately one half cuerda each of onions, carrots, cab-
bage, beets, lettuce and celery, whereas a farmer with only one cuerda might
intercrop several of these same vegetables. Although such crowded combi-
nations results in inferior produce that bring lower unit prices, total yields
justify the practice. In both cases the actual mix of crops and quantity plan-
ted reflect market expectations and risk reduction.
Spacing along rows is not exceptionally close in these systems. Intervals
correspond closely to minimum recommendations in common guides to tro-
pical horticulture 4. The big difference is in row spacing which in less inten-
sive or more mechanized systems is set by the needs of cultivation tools or


irrigation furrows and usually is two or three times as great as plant spacing.
Since hand cultivated and irrigated systems in Middle America do not need
wide rows for equipment access, row spacing is the same as plant spacing, and
plant densities are two or three times higher.
In addition to multiple cropping on plot surfaces, maximum use is made
of field edges and borders where medicinal and speciality plants and herbs
are planted. Even canals are productive : in Quezaltenango watercress (Nastur-
tium officinale) is harvested every 40-45 days during the growing season for
sale in local markets. In southwestern Tlaxcala, Mexico, an important cottage
industry of woven sleeping mats depends upon tule (Scirpus spp.) planted in
field drains. Thus to the general notion of space utilization in cultivated
fields must be added the possibilities for exploiting other productive microenvi-
ronments within the general farming region 5.
Often crops in intensively managed vegetable fields are of different height.
Thus root and tuber crops, such as beets and potatoes, may share horizontal
space but not vertical space with stem or leaf crops such as celery or spinach.
Greater stratification occurs in the traditional subsistence combinations of
maize, beans, squash, and other native plants commonly found in field combi-
nations. Still further exploitation of different horizontal planes is possible
by combining crops of widely different growth habits, such as economic shrubs
or trees, with field or garden crops. Orchards of apples, apricots, capulin
(Prunus capuli), peaches, pears, and tejocote (Crataegus mexicana) with understo-
ries of maize and beans are found on the slopes of Popocat6petl and Ixtacci-
huatl and elsewhere in highland Middle America.
Such high and low tree and shrub crops are even more common in the tem-
perate (templada) and hot (caliente) zones. Shading the beverage plants, cacao
and vanilla, appears to be an ancient practice. Multiple stories of coconuts
over papaya over cacao, bananas, or oranges are found all along the central
and southern Caribbean coastal plain of Mexico. Field and garden crops
such as maize, yuca or casava (Manihot esdulenta), and beans are planted under
these tree and shrub combinations to create a four or even five layer crop mix
in which none of the separate canopies compete for space. There is, however,
competition below ground and such combinations usually are limited to areas
where neither precipitation nor solar energy is lacking.
The fullest exploitation of vertical as well as horizontal space is found in the
multi-storied dooryard gardens of Middle America. Since these have been
discussed at length elsewhere 6 they need not be reviewed in detail here. Plots
of no more than one-tenth hectare may contain two dozen or more different
economic plants, each with distinctive space requirements 7. A garden in
the templada region near Atlixco, Puebla, will serve as an example. The plot
displayed a seemingly random horizontal distribution but a rather carefully
arranged four tier vertical arrangement of tall trees, such as mango, papaya
(Garcia papaya), capulin, and guaje (Leucaena esculenta); a great number of
medium-height trees and shrubs, including banana, peach, avocado, pome-
granate, several types of citrus, coloring (Erythrina americana), chirimoya
(Annona cherimola), and kumquat (Fortunella spp.); and lower layers of high
and low field crops such as maize, shrub beans, red and husk tomatoes, chile,


and squash, interspersed with flowers and medicinal and cooking herbs. Econo-
mic vines including beans and chayote (Sechium edule) twined into otherwise unoc-
cupied spaces. The whole garden was fenced around with additional produc-
tive and ornamental plants, such as colorin, the bamboo-like carrizo (Arundo
donax), and jacaranda (Jacaranda acutifolia). Finally, as if the floristic exube-
rance were not enough, chickens and turkeys patrolled between plants and
contributed in their way to the output of this productive, three-dimensional
There are advantages to intercalating other than intensive use of space and
greater total productivity. Multiple cropping reduces erosion by maintaining
a nearly continuous plant cover over the soil for most of the year. Tall plants
provide support for climbing vine crops, and leguminous plants replace soil
nitrogen to the benefit of the whole crop complex. Multiple cropped fields
are less subject to infestation by above-ground pathogens and pests 8. And
diverse crops, especially if of different growth habits, replicate the structure
and diversity of natural stands and create desirable, sheltered microenviron-
ments 9.
These features, long appreciated by traditional farmers, are attracting the
attention of scientific investigators. Thus Greenland presents data from
the International Institute of Tropical Agriculture (IITA), Ibadan, Nigeria,
that show reduced erosion and increased total yields from mixed crop fields,
and recommends the practice as part of a farming system suitable for the lowland
humid tropics 10. At Centro Agron6mico Tropical de Investigaci6n y Ense-
fianza (CATIE), Turrialba, Costa Rica, recent research indicates that multiple
cropped fields produce more biomass, and more usable total product than mono-
cultural systems and have fewer weeds and airborne diseases. In general,
however, labor requirements are higher and less uniform 11
Despite the advantages of intensive utilization of field space, it is doubtful
if many farmers would practice the techniques if space were not a limiting fac-
tor. There are several reasons for this. Most farmers feel that although total
yields from multiple cropped fields are higher, production and quality of indi-
vidual crops are not as good as they are when planted separately. In addi-
tion, multiple cropped fields are considered more laborious. They are diffi-
cult to work with animal-drawn equipment. Even in hand operations, possi-
bilities for working rapidly with uniform repeated movements are reduced or
eliminated. The CATIE findings generally bear out these impressions. Ander-
son 12, however, argues that mixed gardens make very efficient use of culti-
vator's time. Additional research could clarify this issue.


Crop scheduling, or managing and minimizing the time a crop is in the field,
may be as important as crop spacing for increasing production per unit of
area. Together, the two sets of techniques form a powerful system for inten-
sifying use of productive space. Simpler forms of scheduling, such as crop
rotation, are practiced in Middle America wherever growing seasons permit two


or more crop cycles each year. Examples of complex scheduling, where crops
at different stages are grown together in the same field, are less common. Appa-
rently the ability to coordinate and integrate planting, cultivating and har-
vesting phases of several crops at different stages of growth is a skill shared by
relatively few farmers. The examples are worth noting, however. In the
following discussion, general comments based upon field observations are
followed by a more detailed review of seedbeds, one of the more important time
and space conserving techniques used in Middle America.

Successive Crops.

In its simplest form, scheduling involves nothing more than planting two
or more crops in sequence so that productive space is used for as much of the
agricultural year as possible. The main limiting factor is climate : there must
be enough energy and moisture for enough time to permit two or more crop
cycles during the growing season. But since length of growing season also
is a function of growth periods and requirements of particular plants, in reality
it is a combination of climate and crops that establishes opportunities for
successive crops in the same year 13.
Growing seasons- are limited by temperature or precipitation. Both can
be managed by traditional farmers. Irrigation and moisture conserving prac-
tices compensate for lack of rainfall. Even cold weather or frost hazards can
be partially offset by careful management of field microclimates 14. Thus,
the amount of time a farmer can work his productive space depends upon regio-
nal and local climate conditions, crop characteristics, and mastery over agri-
cultural resources such as water and climate.
In most traditional systems, allowance must be made for a basic subsistence
food plant. In Middle America, successive crops are planted only if the gro-
wing season is long enough to accommodate maize and one or more other crops.
For example, one simple and popular highland succession consists of garlic
(Allium sativum), planted in late fall and harvested just before spring rains
begin, followed by maize planted in late spring and harvested in early autumn.
Garlic is a cash crop ; maize is for farm family consumption. This example
also illustrates the variable nature of growing seasons ". Garlic thrives in
the cool, dry winters of highland Middle America whereas maize needs the
warm, moist conditions of summer.
Substituting shorter term crops, such as lettuce or radishes, for relatively
long-term garlic or shortening crop field time by planting seedlings from nur-
sery beds might permit a three-crop cycle. But the real opportunities for
successive crop cycles occur when the production of subsistence maize is remo-
ved from crop sequences. Liberated from long-term, space-expensive maize,
plots devoted exclusively to commercial crops can be scheduled through three
and even four cycles each year.
Thus one step in the intensification process is specialization of farm space.
Since even the most commercially-oriented traditional farmers continue to
rely upon home-produced food, maize production must continue. But instead
of alternating with commercial crops, the staple grain is relegated to less-inten-


sively managed, temporal fields, often in hilly areas, leaving the prime, inten-
sively managed plots exclusively in commercial production.

Phased Planting.
Scheduling also may assume more complicated forms, as when plants with
different growth and maturation periods are planted together, or at staggered
planting dates so that crops in the same field are at different stages. By this
means it is possible to continuously use not only horizontal but also vertical
spaces that otherwise could go unoccupied. Possibilities for different crop
combinations and schedules are without limit. For example, an irrigated,
one-fifth hectare subsistence plot in Tlaxcala, Mexico contained seven different
crop plants in different stages of growth : mature broad beans (haba), chick-
peas (garbanzo), and peas (arveja, chicharo), and young maize (maiz), climbing
and shrub beans (frijol enredador, frijol de mata), and squash calabazaa).
The first crop contained chick-peas, broad beans, and peas, all of which
were mature and being harvested. When the last of these were picked, the
plants were removed (and used for fodder) exposing the second phase maize,
bean, and squash seedlings that originally were planted in furrows between
rows of broadbeans. In the second phase rows were cross-plowed so that the
maize and associated plants were on ridges.

furrow. ^ 7 =- broad bean and peon
ridge -chickpea
furrow m f I ;maize and climbing been
I l Ils I t.shrub bean
furrows crossplowed -squash
for Mscond phase ah

In this particular example, successive crop phases are almost structural
duplicates. Each contains an emergent support plant (broad beans, maize),
twining associates (peas, enredador beans), and intercalated shrubs (chick-
peas, mata beans). Only the ground-hugging calabaza of the second phase
has no morphological counterpart in the first.
By incorporating quick-maturing vegetables, possibilities for scheduling
increase enormously. For example, on the commercial vegetable terraces
(tablones) of Quezaltenango, Guatemala, radishes with a maturing period of
30-35 days are planted with lettuce which has an expected field time of 2 1/2
months. Some 20 to 30 days later, cauliflower (2 1/2 to 3 months) is interca-
lated. Radishes are harvested before the lettuce grows to occupy much of
the near-surface space. The taller cauliflower matures after the lettuce has
been picked. Thus although horizontal space is continuously occupied, compe-
tition for vertical space is minimized. In several vegetable regions of Guate-
mala and Mexico, scheduling and multiple cropping are carried out during
three separate crop phases. Farmers boast that if they harvest on Friday,
they prepare the fields on Saturday and plant again on Monday.


Longer term scheduling opportunities arise when crop mixes include peren-
nial shrub or tree crops. Thus grains and pulses commonly are planted in the
open ground between rows of avocado (Persea americana), citrus, or mango (Man-
gifera indica) seedlings in new orchards. Only after several years will spreading
canopies reduce surface energy levels below those required for field crop growth
and development and restrict interculture to more shade-tolerant ground crops.
In dooryard gardens, complex spatial arrangements are paralleled by equally
complex scheduling. Planting takes place continuously and harvesting of
seeds, stalks, leaves, roots, tubers, flowers, and fruits is a never-ending process.
Until a more precise timetable of operations is developed, Anderson's descrip-
tion of a Guatemalan garden will serve 15 :
The garden was in continuous production but was taking only a little effort at any
one time : a few weeds pulled when one came down to pick the squashes, corn and bean
plants dug in between the rows when the last of the climbing beans were picked, and
a new crop of something else planted above them a few weeks later.

If seeds are planted directly in fields at intervals appropriate to mature plants
then for weeks or months tiny sprouts and seedlings utilize but a fraction of
the productive space. One solution is to set aside special planting areas or
seedbeds (Spanish from the Latin, sementeras ; Spanish from the Arabic, almdci-
gas; Nahuatl centemilli, tlachtli) and thus substitute an early microspace period
for part of total field or macrospace time. The results are significant. For
example, in Oaxaca, Mexico, tomatoes commonly are started in seedbeds
around the first of November, transplanted to fields in mid-December, and
harvested during a two-month period from April to June. Thus, the field
period of tomatoes is reduced by 20 to 25 percent during which time field space
can be used by other crops. Even greater space savings are realized with
onions which pass 1 1/2 to 2 months en almdciga followed by an additional
three months in the fields, for a total saving of 30 to 40 percent of field time.
Other annuals often started in seedbeds are celery, cabbage, beets, lettuce,
swiss chard, cauliflower, leeks, and rutabaga. Although grains generally
are sown or planted directly in fields, maize still is occasionally started in seed-
beds in the extraordinarily crowded chinampa regions of Mexico 16.
The essence of seedbeds is that crops occupy only a fraction of scarce field
space for significant portions of their life. Understandably, the longer the
seedling stage, the more impressive the saving. One of the most striking
examples involving annual plants is chile (Capsicum spp.) grown on the Mesa
Central of Mexico. Seeds are first sown in November or December on care-
fully prepared and manured seedbed surfaces, then sprinkled with dirt (tapar
con tierra) and covered with a layer of branches weighed down with earth to
insulate them against frosts. After a month or so the overlying dirt and branches
are removed (destapar) and the branches are formed into arbors (jacales, lit.
huts) that continue to offer protection against frost, hail, and birds. At this
stage counts of seedlings in randomly selected 20 cm X 20 cm quadrats revea-
led seedling densities from zero to 200 with an average of about 60 plants per
400 cms, or about 1,500 per square meter.


Chile seedlings continue development for another three to four months,
then about mid-April are transplanted to open fields. Seedlings are trans-
planted in bunches of three to six (average = four) and depending upon the
type, are spaced 30 to 50 cm apart usually in staggered rows :

*000000 oo

Staggering in this fashion maintains standard intervals between plants and
yet saves about 13 percent of field space compared to opposed planting. At
30 cm spacing each cluster of transplanted seedlings takes up about 0.08 m2
and about 0.22 m2 at 50 cm spacing. Since seedbed density was 1,500 per m2
and each transplanted cluster contains an average of four seedlings, expansion
factors from seedbeds to fields range from 1 : 30 to 1 : 75. That is, one square
meter of chile seedbed will supply seedlings for 30 to 75 m2 of field space.
Chile is harvested in September and October. Thus of a ten to eleven month
total growing season, some 40 to 50 percent may be spent in seedbeds. Or
put another way, the chile crop occupies only 2 to 4 percent of productive
field space for almost half the total growth period.
The benefits are substantial. In frost-free regions, the four or five months
seedlings spend in almacigas are enough to produce another crop in the main
field, such as green maize for roasting ears or vegetables. In colder climates,
elaborately constructed almacigas protect delicate seedlings against frost and
permit cultivation of slow-growing crops that otherwise would be impossible. On
the cool Mesa Central of Mexico, for example, chile production would be extre-
mely hazardous without early protection of elaborately constructed seedbeds.
Even in space abundant systems, savings in field space and ease of caring
for seedlings prompts use of seedbeds for slow growing plants. For example,
such tree or shrub crops as coffee, citrus, and cacao commonly are started in
seed or nursery beds. The concern here is to commit field space for the long
periods of plant life only to those plants with the best prospects for growth
and production. In seedbeds seedlings can be observed continuously, and
their environment managed to insure optimum amounts of fertilizers, water,
and light during early growth stages. At transplanting time, field space is
committed only to the most promising.


By incorporating crops that occupy different horizontal and vertical spaces,
multiple cropping creates three-dimensional plant matrices that make efficient
use of field space. When coupled with scheduling, or timing of crop sequences,
use of various spaces becomes more continuous. A further step is to set aside
separate areas where crops pass germination and early seedling stages under
special care, and where they occupy only a fraction of valuable field space.
Integrating production from seedbeds into intercalated and phased cropping


systems permits exceptionally tight scheduling and further reduces losses of
productive field space time.
Close management of field space and schedules increases productivity per
unit area. It comes at a price, however. The highest crop densities are found
in farming systems that use the least fossil fuel or even animal energy supple-
ments and the most human labor. Intensive crop scheduling requires close
control of soils, water, and other elements of the crop environment. Although
seedbeds save substantial amounts of field time, by definition they involve
arduous transplanting, an operation that has become symbolic of hard field
labor. Thus, space and time conserving methods are employed where space
is physically, socially, or economically scarce, and appear to be a response to
that scarcity.


1. Food and Agriculture Organization of the United Nations, Report on the 1960 World
Census of Agriculture. Rome : 1971.
2. Some writers argue that such factors as physical circumscription and population pres-
sure, act as stimuli to intensification and subsequent social and political change, e. g., Ester
BOSERUP, The Conditions of Agricultural Growth. Chicago : Aldine Publishing Company,
1965 ; Robert L. CARNEIRO, A Theory of the Origin of the State. Science Vol. 169, 21 August
1970, pp. 733-738. H. C. BROOKFIELD, however, rejects any simple relationship between
population and intensity of cultivation. Intensification and Disintensification in Pacific
Agriculture ". Pacific Viewpoint Vol. 13, No. 1, May 1972, pp. 30-48.
3. For example, the FAO-UN Report op. cit. (see footnote 1), p. 115 mentions that signi-
ficant problems were encountered in the reporting of areas for crops, relating to areas where
crops were grown simultaneously on the same land and to areas where they were grown
successively on the same land more than once during the agricultural year ".
4. E. g., Luis Alsina GRAU, Calendario del Horticultor. Barcelona : Editorial Sintes, S. A.,
1973; Ernest MORTENSEN and Ervin T. BULLARD, Handbook of Tropical and Sub-tropical
Horticulture. Washington, D. C. : Department of State, Agency for International Develop-
ment, 1964; H. D. TINDALL, Commercial Vegetable Growing. London and Ibadan : Oxford
University Press, 1968.
5. Exploitation of microenvironments in one heavily farmed region is described by Gene
C. WILKEN, The Ecology of Gathering in a Mexican Farming Region ". Economic Botany,
Vol. 24, No. 3, July-September 1970, pp. 286-295.
6. E. g., Edgar ANDERSON, Plants, Man and Life. Berkeley and Los Angeles : Univer-
sity of California Press, 1967 ; Clarissa KIMBER, Dooryard Gardens of Martinique ". Yearbook
of the Association of Pacific Coast Geographers, Vol. 28, 1966, pp. 97-118; Spatial Patterning
in the Dooryard Gardens of Puerto Rico ". Geographical Review, Vol. 63, No. 1, January 1973,
pp. 6-26; Philip L. WAGNER, Nicoya : A Cultural Geography. Berkeley and Los Angeles :
University of California Publications in Geography, Vol. 12, No. 3, 1958, pp. 195-250.
7. Farmyards in industrial societies have become machinery depots; open areas with
packed or even paved surfaces used for storing and manoeuvering large powered or pulled
equipment. These most accessible lands, which theoretically should be the most intensively
cultivated, are as devoid of life as parking lots which in a sense they are. In nonindustrial
societies houseyards often are the most productive parts of farms. With no need to assign
space for storage of bulky equipment, dooryard plots can be devoted to cultivation of choice,
delicate, or experimental plants as well as basic crops.
8. Hans RUTHENBERG reviews advantages of mixed cropping and phased planting within
the context of shifting cultivation systems. Farming Systems in the Tropics. Oxford :
Clarendon Press, 1971, pp. 28-30.
9. Field microclimates are discussed by Gene C. WILKEN, Microclimate Management by
Traditional Farmers ". Geographical Review, Vol. 62, October 1972, pp. 544-560.
10. D. J. GREENLAND, Bringing the Green Revolution to the Shifting Cultivator", Science,
Vol, 190, 28 November 1975, pp. 841-844,


11. CATIE, Food Production Systems Preliminary Results ". Activities at Turrialba,
Vol. 3, No. 2, April-June 1975, pp. 2-4.
12. ANDERSON, op. cit. (see note 6), p. 141.
13. Jen-hu CHANG, A Critique of the Concept of Growing Season ". The Professional
Geographer, Vol. XXIII, No. 4, October 1971, pp. 337-340.
14. WILKEN, Op. Cit., (see note 9).
15. ANDERSON, op. cit. (see note 6), p. 141.
16. Robert C. WEST and Pedro ARMILLAS, < Las Chinampas de MBxico : Poesia y Realidad
de los Jardines Flotantes s ". Cuadernos Americanos, Vol. 50, No. 2, March-April 1950,
pp. 165-182.




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