Field Research Brief No. 15 L PUSLITTAN
June, 1985 ST SUMAT
TITLE: Residual and Maintenance Rates for Lime
EXPERIMENT NO.: 1203
RESEARCHERS: Mike Wade, E. J. Kamprath, and Djoko Santoso
1. To determine the critical level of soil acidity
parameters) for optimum production of upland rice and soybeans,
2. To determine a method of predicting lime rates necessary i
achieve a specified level of soil acidity,
3. To determine the annual lime application rate required
to maintain a specified level of soil acidity,
4. To monitor the residual effects of various rates of lim-
applications on a rotation of rice and soybeans.
SOIL: Typic haplorthox, Ceak; bulldozer cleared in 1978, annual
cropping of upland rice without lime or fertilizer input.
A. Initial Lime Rates B. Management
1. 0 tons/ha 1. residual
2. 0.5 (3/8 X exch. Al) 2. annual maintenance
3. 1 3/4 applied on a per-
4. 2 1.5 plot basis aimed
5 4 3. at 60, 40, 20, 10
and 0% Al sat, re-
Lime source is Ca(OH)2.
CROP: Soybeans (second season), cv. Orba, planted 20 X 40cm X 3
seeds/hole, in February and harvested in May, 1985. Pesticides
were: carbofuran 36 applied with seed at planting and weekly
sprays of endosulfan (1.5 1 a.i./ha) beginning after flowering
and continuing until near physiological maturity. Base fertili-
zers. included 20 kg P, 50 kg K, 16 kg Mg and 23 kg S/ha. Niftal
inoculum was.seed applied.
RESULTS: The soybean crop grew well despite the relatively dry
weather that caused several short, but serious water stress
periods for the crop. Insect damage was minimum and the well-
limed plots yielded >1.5 t/ha. Figure 1 shows the .yield response
of the beans as effected by lime rates. The residual plots, i.e.
those that had only the indicated rates at the initiation of the
experiment in Sept, 1983, show a linear response to the lime
rates. The maintenance plots, those that get an annual mainten-
ance application of lime, indicate a steeper response with maxi-
mum yield occurring near the 2 t/ha "maintained" treatment.
Acid (Al+H) saturation proved, as last year, to be a good
indicator of soybean response. Figure 2 shows the two years' data
combined for a regression of acid saturation on soybean yield.
It is remarkable how similar the data for the two years fit
together. However, again like last year, no plateau or critical
level is defined as the regression is linear- from 0%. This :is
somewhat different from other lime trials on soybeans i.n
TROPSOILS (see FRD #10) which indicate a linear plateau
relationship with the plateau intercept occurring just below 30%
acid saturation. These are with the same variety and grown more
or less at the same time, but of course at a different location.
This trial is on an oxisol, and the soil is a brighter red and
appears more highly weathered than the soil of the other trials.
Also the lime used here is burned lime' (Ca(OH)2) whereas the
others use ground limestone (CaCO3). Whether possible
mineralogical differences and/or lime source differences account
for this discrepency in soybean tolerance is unknown at this time.
One goal of our research is indeed to find a method of predicting
lime requirements across a wide range of conditions, so now we
have the challenge of trying to blend and unify this seemingly
* .i I.
. :. '
' I, I
o y Y I 1 "L S
:. *;";' ]i :'r .,. i: : ( .- o.iz L
I o : 1 -. : : *
I : ;- _? r y i l i : ,
I ". ..,^ I : :, v i '
'. / -- ^ i .- . .. : '' ', .' <''
I \ /, j :,9 :F '
' : I | I; ': \ ', t *
ii f1 /
. I .. I '
,. : I ; .
I I I