Field Research Brief No. 27 .i
March, 1986 .
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 to
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 lime
applications on a rotation of rice and soybeans.
SOIL: Typic haplorthox, Ceak; bulldozer cleared in 1978, an--ual
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 a ned
5 4 3.0 at 60, 40, 2;, 10
and 0% Al sa:, re-
Lime source is Ca(OH)2.
CROP: The experimental plots were planted to upland rice, 1'2 to
cv. Sentani (an improved Indonesian variety) and 1/2 to cv.
Maritik (a local rice). Plant spacing was 25x25 cm for both
varieties, and base fertilizers were also the same, namely 3C kg
N (as urea), 20 kg P (as TSP), 25 kg K (as KC1) and 50 kg kieser-
ite (MgSO .H20)/ha. Insect control was accomplished with granu-
lar carboluran (1 kg a.i./ha) at planting and periodic sprays
with Sevin and Diazinon.
RESULTS: Plant population and general growth was very good. No
obvious nutritional symptoms were exhibited at any time during
the crop cycle. Neither rice variety had grain yield responses
to lime (Figure 1). This is in contrast to the rice (cv. CIT- 7)
grown the first two years of this experiment. As reported earli-
er, that variety responded to lime and gave an apparent critical
level for acid saturation of 40%. Since neither of the two
varieties used this season showed any response to lime, no criti-
cal level is indicated except that they tolerated the 60-707 AS
of the unlimed plots. This 85/86 season was one of high and
frequent rainfall. Very little Al toxicity/Ca deficiency symp-
toms were seen in any of our trials (limed or unlimed). This is
in sharp contrast to the previous season, when we had a "dry" wet
season, and the characteristic yellowing and drooping outer
leaves of rice on the more acid soils was prevelant. It is known
that Al is particularly toxic to roots. Under ideal moisture
conditions, it is possible that even a damaged root could func-
tion enough to supply water and nutrients as needed by the plant.
But under moisture stress, it's functioning would be quickly
curtailed, whereas a healthy root could presumably continue to
function adequately under some stress. Thus, it is probable that
there would be a season by lime interaction. During a well-
distributed rainfall season, no response would be seen (as exper-
ienced this year), but in a drought-prone season, a lime response
would be more likely (such as last season). Unfortunately Sen-
tani was not grown last season, such that this interaction is
confounded by having used different varieties. The CIAT-7 was
not used this year because it seemed to be poorly suited fcr
Sitiung and had an uncommonly low tolerance for soil acidity.
There were distinct growth differences between the two
varieties, as the shorter Sentani produced higher grain yields
with less straw, and therefore had a much higher grain:stra'
ratio than the local variety (Table 1). Only plant height,
however, was effected by lime, and that positive effect was
exhibited for both varieties. It is often said that improved
varieties are more susceptible to soil acidity and/or infer-ility
than local varieties, and we have heard that specific argument
regarding Sentani. Yet in these side-by-side plots, Sentari has
tolerated rather severe soil acidity just as well as a local
variety. Therefore one should be cautious about making
generalizations without support data.
There are two potentially important factors that should be
considered in evaluation these rice varieties. One, there -as
generally a light incidence of blast in the Sitiung area this
season. Although there was little blast damage to either vari-
ety, of the two, Sentani would probably be much more susceptible
to blast in a "bad" year, as was the case last year (84/85) when
grain yield of Sentani in some trials was completely annila:ed..
Two, a rather unusual phenomena was noted regarding wild pigs.
They had an obvious preference for the Sentani. The Sentani
flowered earlier than Maritik, but the pigs went right by farmer-
planted local rice that was in grain fill stage in order to get
to the Sentani. They did not bother the Maritik during grain
fill. We have no inclinations for why wild pigs would prefer
Sentani. However this is an example of the practical obser:a-
tions and benefits of conducting research on farmer fields.
Table 1. Yield Parameters of Two Upland Rice Varieties, a local
(Maritik) and an improved (Sentani).
no lime 1.9 3.6
+ lime 2.2 3.5
CV % 18.2. 14.9 19.2
* all differences between the local (Maritik)
(Sentani) are significant at P.01
" differences between no lime and + lime are
except for plant height @ 60 dap
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