Group Title: TropSoils field research brief ;, 31
Title: Mg fertilization for annual food crops
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 Material Information
Title: Mg fertilization for annual food crops
Series Title: TropSoils field research brief ;, 31
Physical Description: 2, 2 leaves : ill. ; 28 cm.
Language: English
Creator: Gill, Dan.
Aribawa, I. B.
Wade, M. K. (Michael Karl)
Lembaga Penelitian Tanah.
Soil Management Collaborative Research Support Program.
Publisher: Soil Management Collaborative Research Support Program, North Carolina State University,
Publication Date: 1986
Subject: Soil management -- Indonesia.
Soils -- Magnesium content -- Indonesia.
Food crops -- Indonesia.
Spatial Coverage: Indonesia.
General Note: Caption title.
General Note: "June, 1986."
General Note: At head of title: TropSoils-Indonesia, Centre for Soil Research.
 Record Information
Bibliographic ID: UF00080607
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 157036227

Full Text


Centre for Soil Research
Field Research Brief No. 31
June, 1986

TITLE: Mg Fertilization for Annual Food Crops

RESEARCHERS: Dan Gill, I B. Aribawa, and Hike Wade


OBJECTIVES: 1. To study crop response to iHg fertilization for
a low input system (rice and peanut rotation)
and a high input system (corn and soybean rota-
2. To determine critical M1g soil test levels
for the crops in the rotations being studied,
3. To compare the effects of yearly applications
vs. per-crop applications of .;g on yields and
soil test levels,
4. To monitor Mg movement within the soil profile
under low and high input systems.

Dystropept (FCC: Cak) Cleared from vir in forest by
bulldozers in 1076, abandoned to grass nd bush fallow
since 1978.

MgS04 .


base fertilizers:
lime (t/ha)-
N (kg/ha)-
P (kg/ha)-
K (kg/hc)-

lowing rates of Ng fertili
;20, and base fertilizers w

Low Input


4 per crop

2.5 (<40% Al sat)
50 (rice only)
40 + 10/crop

zer, as kieserite-
ere applied:

Higc Input
(corn soybean)

E per crop
16 "

5.0 (
150 +

Elemental sulfur (flower of sulfur) wa-s appli
that was applied as SOC in the kieserite to a
kg S in the Low In-ut and C3 kc in the Hicch

<10r Al sat)
corn only)

d to balance the S
constantt rate of 62
Input system.


CROP HISTORY: Peanut and soybean were planted in February, 198G
in the low and high input systems, respectively. Both were
planted with dibble stick at 20::40 cm spacincs. Peanut was sown
with 2 seeds/hole and soybean with 3 seeds/hole. No insect
control was needed for peanut, but soybean was protected with
carbofuran at planting (3G in seed hole at 1 kg a.i./ha) and
weekly sprayings with endosulfan during pod formation. All weed
control was done by hand. Ease fertilizers (P and K) were ap-
plied according to the system pl-an (see above). Additional Mg
fertilizer was applied in the per-crop treatments only. Lime was
not reapplied to any plots.

RESULTS: The yields of the two crops as affected by treatments
are shown in Figure 1. Soybean reached plateau yields with the
residual of 24 kg Mg/ha, whereas peanut did so with the residual
of only 8 kg/ha. Soybean also responded positively to the second
per-crop applications of 8 and 16 kg Mg/ha (total of 16 and 32
kg Hg/ha, respectively) but peanut did not respond to the
repeated applications of 4 and 8 kg/ha.

Figure 2 show the effect of the Mg fertilizer applications
had on soil exchangeable Hg. For both the low and high input
systems, the added fertilizer linearly increased soil Mg.
However the low input system (with lower rates of lime) had
consistently higher levels of Mig across the range of fertilizer
rates, except for the highest rate. Apparently the higher rate
of lime reduced the amount of Hg retained on the exchange sites,
even at the zero rate of Mg.

Figure 3 shows the crop yields as related to exchangeable
Mg. A linear-plateau model fits each crop response to levels of
Mg, and well describes a critical value for each (0.21 meq for
peanut and 0.24 meq/100ml soil for soybean). Although the
difference in these values is small, it is sufficient, when
coupled with the reduced Mg retention under high lime (Fig. 2),
to explain the 3-fold difference in optimum ig fertilizer rates
between the two crops (Fig. 1). Also, Figure 3 indicates that
the responsiveness of the two crops to iHg is actually quite
similar. The higher li..e rate of the high input system resulted
in lower exchangeable Mg and thus amplified the soybean response
to IHg fertilizer, and is not simply a case of soybean being more
demanding of soil Hg.

* reP f +


o 8 16 2# 32 46 64
Applied mg .{qA^
FRei L Ke s ose ef PedAr ( 4^Iro6)
d.L Soybheai (#;4 I.npa f
fer /ze-r (2; S -0 zo)

a *
Vr e
k) o .20

o 4 8 16 2.4 32.
App lied

F;3urte, Efft'f mi S;lize
cOA ksO;/ XC-e a g.t Z /eme, o, .
hl3 A. &f 4 6low b=d .fimt 0nd
Ar ^l lize, <^ & /cd/'ois.

Soy eo-.

. Res; o u4
x per C C' t2

S=.4 I,& Zp
Y=./N7 -.tcs9

46 ( 6/h

mV 3/ko)

, .17^.0^5


tb i.o r x P
is oy &e

o .20 ,Y
EOchan edle M3

fi k a 3. Rseld ians h/
hemieen sao/ybeaiad Ph^ /^
&ce l f

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