Rice response to K fertilization, residue management and green manure application in Sitiung V

Material Information

Rice response to K fertilization, residue management and green manure application in Sitiung V
Series Title:
TropSoils field research brief
Gill, Dan
Kasno, Anotonius
Lembaga Penelitian Tanah
Soil Management Collaborative Research Support Program
Place of Publication:
Raleigh, NC
Soil Management Collaborative Research Support Program, North Carolina State University
Publication Date:
Physical Description:
2, 2 p. : ill. ; 28 cm.


Subjects / Keywords:
Rice -- Fertilizers -- Indonesia ( lcsh )
Soils -- Potassium content -- Indonesia ( lcsh )
Green manuring -- Indonesia ( lcsh )
Spatial Coverage:


General Note:
Caption title.
General Note:
"February, 1986."
General Note:
At head of title: TropSoils-Indonesia, Centre for Soil Research.
Statement of Responsibility:
researchers, Dan Gill and Antonius Kasno.

Record Information

Source Institution:
University of Florida
Holding Location:
University of Florida
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The University of Florida George A. Smathers Libraries respect the intellectual property rights of others and do not claim any copyright interest in this item. This item may be protected by copyright but is made available here under a claim of fair use (17 U.S.C. §107) for non-profit research and educational purposes. Users of this work have responsibility for determining copyright status prior to reusing, publishing or reproducing this item for purposes other than what is allowed by fair use or other copyright exemptions. Any reuse of this item in excess of fair use or other copyright exemptions requires permission of the copyright holder. The Smathers Libraries would like to learn more about this item and invite individuals or organizations to contact Digital Services ( with any additional information they can provide.
Resource Identifier:
156976313 ( OCLC )

Full Text

Centre for Soil Research
Field Research Brief No. 25
February, 1986

Title: Rice response to K fertilization, residue management and
green manure application in Sitiung V

Experiment No.: 3501

Researchers: Dan Gill and Antonius Kasno

Objectives: 1. To examine the effects of K rates on rice growth
and soil extractable K,
2. To compare crop response to K under
different organic material management.

Soil: Orthoxic tropudult (FCC:Ceak) cleared in 1982 with
bulldozers never cropped until this experiment in 1934

Treatments: Treatments are an incomplete factorial set out in a
randomized complete block design with 3 replications.
Six rates of K, as KC1 fertilizer, were applied to
plots having previous crop residues removed: 0, 20,
40, 80, 120, and 240 kg K/ha. Three rates (0, 40 and 80 kg K/ha) were applied to plots having residue from
the pruhious rice and soybean crops and also weeds
(primarily a grass, tentatively identified as Paspalam
sp., which had grown during the dry season)
incorporated. The 40 kg K/ha plus crop residues
treatment was formerly a 10 kg K/ha residues removed
treatment in the previous year. Green manure
treatments of 10 t fresh Calapogonium were made (as per last year) in combination with two levels of K
fertilizer, 0 and 80 kg K/ha.

Crop History: Upland rice, cv. Sentani, was planted on Sept. 28,
1985, with a blanket application of the following
fertilizers (in kg/ha): 100 TSP, 125 kieserite and 33 urea applied twice (at 1 and 2 months after planting).
Curaterr 3G (carbofuran) was applied at planting at a
rate of 30 kg/ha. Several sprays of Sevin and
Diazinon were made during grain filling. Harvest
occurred on January 19, 1986, 114 days after planting.

Results: As preparations were being made to replant this experiment after an unusually wet dry season, it was noticed that weed growth (primarily a grass tentatively identified as a Paspalam sp.) was related to treatment. This weed (grass) growth was cut and weighed, with results in Figure 1. With previous crop residues removed, grass dry weight had a linear correlation of Y=
0.87 + 0.019 applied K and an R =0.97. Returning crop residues


gave higher yields at 0 and 80 kg K/ha while green manure applications gave the highest yields at these 2 rates.

Grain yields of rice were quite high (Figure 2), due to very wet weather and low pest pressures. Plateau yields of 3.5 t/ha were 6-7 times greater than yields without KCl fertilizer -nd with residues removed. A rate of 80 kg K/ha was sufficient to reach the plateau. Crop response to fertilizer K with residues returned was not as strong, primarily because yields at 0 K were much higher (above 2 t/ha). It seems evident that recycling of crop residues in these soils is very important, especially at low rates of K fertilizer. Figure 2 illustrates that simply returning crop residues (with no KC1 applications) gave equivalent yields to those achieved with 20 kg K/ha when crop residues were removed. Green manure applications were even more effective at increasing grain yields when no K fertilizer was applied.

Table 1 shows the effects of treatments on blast
(Pyricularia oryzae Cay.) incidence at both 54 and 82 days after planting. Potassium fertilizer was very effective at decreasing blast scores, and less blast occurred when residues were returned. Application of green manure apparently was as effective as KCI in imparting disease resistance to the rice.

The response curve for rice straw yields frm both 1985 and 1986 are shown in Figure 3. Although yields were higher in 1986, response for both years was similar, with plateau yields being achieved at 80 kg K/ha. Green manure treatments are plotted to indicate the total amount of K (organic + fertilizer) being applied (Figure 3), and they appear to coincide with the response curve for KC1 alone. Evidently, the major reason green marJire was so effective at increasing yields in this trial was due to the amounts of K being applied organically.

Meh]ich I extractable K correlated very poorly with grain yield (R =0.30), and further work is in progress to address the issue of soil testing for K in these soils.


Table 1. Effect of K rates,
o$ blast incidence

r idue management and ocv. Sentani.

green ranure

inorganic organic* kg K/ha

20' 40 80 120 240



Blast Rating (0-9) 54 DAP 82 DAP

3.7 2.7 2.0 2.0 2.0 2.0

2.7 2.0 2.0

2.0 1.7

6.0 5.7 4.0 4.0 3.7 3.7

4.7 4.0 4.0

4.7 3.7

* RR=remove residues, IR=incorporate residues, GM=green marnre

* KC1 only R- residue returned i green manure

0 40 80

Figure 1.

.K (kg/ha)


Response of a mixture of primarily grass (probably Paspalum sp.) and a few other weeds to applied K, crop residue incorporation and green manure applications.




p 02
M b2
o, 0i


-- -


2 *- KCl only
( T residue returned
G green manure

N 1

0 40 80 120 240
Applied K (kg/ha)

Figure 2. Sentani rice response to applied K without
returning residue, with residue incororated
and with green manure applications.

8 6

4 Q

CO KC1 applied to rice-85
PI0 KC1 applied to rice-A6
2 4 green manure, rice-85
S2 green manure, rice-R6

0 40 80 120 240
Applied K kg/ha

Figure 3. Rice straw yield response to K fertilization for both rice-85 and rice-86.