IJERD – International Journal of Environmental and Rural Development (2011) 2–1

Research article
erd

Growth and Yield of Organic Rice as Affected by Rice
Straw and Organic Fertilizer
ANAN POLTHANEE
Faculty of Agriculture, Khon Kaen University, Khon Kaen, Thailand
E-mail:panan@kku.ac.th

ARUNEE PROMKHAMBUT
Faculty of Agriculture, Khon Kaen University, Khon Kaen, Thailand

SOMPOTH KAEWRAHAN
Faculty of Agriculture, Khon Kaen University, Khon Kaen, Thailand
Received 16 December 2010

Accepted 25 January 2011

Abstract The objectives of this research were to investigate the effect of rice straw
management and the application of different types of organic fertilizer on the growth andyield of transplanted rice grown under rainfed conditions. The experiment was conductedin  a  farmer’s  field  in  Khon  Kaen  province  in  2009.  A  Randomized  Complete  Block  Design  was used with four replications. The treatments consisted of (1) rice straw incorporation
into the soil, (2) rice straw combined with cattle manure, (3) rice straw combined with bioextracted fertilizer and (4) rice straw combined with cattle manure and bio-extracted
fertilizer. In the present experiment, the rice straw remaining in the paddy field wasincorporated into soil after the rice harvest in April. Then the rice was transplanted inAugust. The amount of rice straw and cattle manure incorporated into the soil were about
5.1 and 9.4 tons/ha respectively, which provided N 129 kg/ha, P 41 kg/ha and K 382 kg/ha.
A liquid bio-extracted fertilizer was applied into the soil during the incorporation of ricestraw at a rate of 30 liters per hectare which provided N 28 g/ha, P 5 g/ha and K 135 g/ha
and foliar application at 60 days after rice transplanting which provided N 1.11 g/ha, P
0.18 g/ha and K 5.4 g/ha. It was found that the application of different types of organic
fertilizer combined with rice straw had a significant effect on plant height, but did notshow any significant effect on leaf area and aboveground dry weight at 30 days after
transplanting and at panicle initiation growth stage. At harvest, total aboveground dryweight and panicle number were significantly affected by the application of different typesof organic fertilizer. The treatment of rice straw combined with cattle manure and bioextract fertilizer gave the maximum panicle number. The treatment of rice straw combinedwith cattle manure gave maximum grain yield, but did not show any significant difference
from the treatment of rice straw combined with cattle manure and bio-extracted fertilizer.
Keywords organic rice, organic fertilizer, cattle manure, bio-extracted fertilizer

INTRODUCTION
Northeast Thailand has 5.27 million hectares of rainfed lowland rice growing area, which is about
57% of the rice growing area in the whole country (Office of Agricultural Economic [OAE], 2006).
The average grain yield in this region is low (2.07 t ha-1) (OAE, 2009), due to unstable water
availability (Bell and Seng, 2004). With the current renewed focus on sustainable agricultural
efficient resources (rice straw) recycling may be an alternative method of soil fertility management
for Northeastern lowland rice producers. Straw management by incorporation into the soils is analternative method to avoid straw burning before land preparation. Cattle manure is commonly anorganic fertilizer available in the farms of the smallholder farmers. The bio-extracted fertilizers arealso can be produced by farmers themselves using organic material wastes available in the farm.
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Present studies were, therefore, undertaken to evaluate the effect of rice straw alone and incombination with various organic sources of nutrients on the growth and yield of organic rice.
METHODOLOGYThe  experiment  was  conducted  in  a  farmer’s  field in Muang Yai village, Khon Kaen province in2009. The soil physio-chemical characteristics before planting are shown in Table 1. Randomized
Completed Block Design with four replications was used. The treatments consisted of (1) rice straw
incorporation into the soil, (2) rice straw combined with cattle manure, (3) rice straw combinedwith bio-extracted fertilizer and (4) rice straw combined with cattle manure and bio-extracted
fertilizer. Rice straw was incorporated after the rice harvest. The amount of nutrients returned to thesoil by incorporating rice straw into the soil was calculated as in Eq. (1).
Rice straw dry weight (kg ha -1 ) x nutrient content (%)
100

(1)

The amount of nutrients in the cattle manure applied to the soil before transplanting two weeks
at the rate of 9,375 kg ha-1 was calculated as in Eq. 2.
Rate of application (kg ha -1 ) x nutrient content (%)
100

(2)

The amount of nutrients in the bio-extracted fertilizer applied to the soil was calculated as in
Eq. 3.
Rate of application (kg ha -1 ) x nutrient content (%)
100

(3)

The bio-extracted fertilizer (vegetable wastes and molasses; by-product of the processing ofsugar cane into sugar, fermented for 7 days) applied into the soil at the rate of 3,125 liter ha-1 two
weeks before transplanting, and foliar application at rate of 1,250 ml ha -1 at 60 days after
transplanting.
Two to three seedlings per hill were transplanted in the first week of July in the pattern of 25 x
25 cm hills. Rice cv. KDML 105 was used in this study. Hand weeding was done one at 60 days
after transplanting. No insecticide and fungicide were used in this experiment.
Five hills from each plot were measured to classify their height at 30 days after transplanting(DAT) and at panicle initiation (PI) growth stage. Five hills from each plot outside the harvestingarea were randomly selected to determine leaf area at 30 DAT and PI. The leaf area was measured
using leaf area meter. Again, five hills from each plot outside the harvesting area were randomly
selected and oven dried at 80 ⁰Celsius for 4 days to determine total aboveground dry weight at 30
DAT and PI. The numbers of panicles per hill in the harvesting areas were measured at harvest time.
For the same samples, ten panicles from each plot were randomly selected to determine the numberof filled and unfilled grains and calculated the percentage of filled grain per panicle. The grain
yield was taken from the 2 x 3 m harvesting area of each plot and calculated as kg ha -1 at 14%
moisture content. The filled grains were randomly selected from the grain yield sample todetermine the weight of 1,000 grains. The data were analyzed using analysis of variance proceduresand LSD was used to compare treatment methods when the F-test was significant.
Rainfall, maximum and minimum temperature were recorded at the Khon Kaen
Meteorological Station 5 kilometers from the site. Weekly rainfall, as well as the maximum andminimum temperature during the growing season is shown in Fig. 1.

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Table 1 Soil physio-chemical characteristics before planting of the experimental field
Soil characteristics
Physical properties1-Sand (%)
-Silt (%)
-Clay (%)
Texture classChemical properties-­pH2-EC (ms/cm at 25 ºC)3
-Organic Matter (%)4
-Total N (%)5
-Available P (ppm) 6-Exchangeable K (ppm) 7-Exchangeable Ca (ppm) 7

Values
83.09
7.60
9.25
Loamy sand
5.24
0.070
0.352
0.02139.20
54.65
485.00

1

Texture: Hydrometer method, 2pH: pH meter (1:1 H2O), 3 EC (1:5 H2O),4O.M.: Walkley and Black method, 5Total N:
Kjeldahl method, 6Extractable P: Bray II and Molybdenum-blue method, 7Exchangeble K and Ca: 1N NH4OAc pH7 and
Flame photometry method.

RESULTS
Plant height
The plant height is not a yield component in grain crops but it indicates the influence of various
nutrients on plant metabolism. It was found that incorporation of rice straw into the soil combinedwith application of cattle manure gave the maximum plant height at 30 DAT and PI stage. The
plant height, however, did not show any significant difference from the incorporation of rice straw
into the soil combined with the application of cattle manure and bio-extracted fertilizer treatment(Table 2).

Fig. 1 Weekly rainfall (mm), maximum and minimum temperature (⁰C) in thefield during growing season in 2009
Leaf area per hill
The leaf area (cm2 hill-1) was taken at the 30 DAT and PI stage. It did not show any significant
difference among the treatments. The leaf area per hill, however, obtained the highest in thetreatment of the incorporation of rice straw into the soil combined with the application of cattle
manure at 30 DAT and the treatment of incorporation of rice straw into the soil combined withcattle manure and bio-extracted fertilizer (Table 2).

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Table 2 Plant height, leaf area and total aboveground dry weight of KDML 105 as affected byapplication of rice straw, cattle manure and bio-extracted fertilizer at 30 days after
planting (DAP) and at panicle initiation (PI) in 2009
Treatments
Rice straw
Rice straw + cattle manure
Rice straw + bio-extracted
fertilizer
Rice straw + cattle manure+bio-extracted fertilizer
F-testCV (%)

Plant height(cm)
30 DAPPI
59.00 b100.75 ab
65.75 a110.35 a
57.65 b96.55 bLeaf area(cm2/hill)
30 DAPPI
525.181358.70869.251642.00
520.351367.80

Total aboveground
dry weight (g/hill)
30 DAP
PI
3.63
19.35
5.05
22.16
2.87
15.68

61.55 ab105.95 ab754.631767.00

4.41

20.27

*
5.05

**
4.17

NS
40.00

NS
4.17

NS
29.68

NS
19.64

Means followed by the same letter at the same column were not significantly different by LSD*,** significant at P<0.05 and 0.01, respectively and NS not significant

Total aboveground dry weight
The total aboveground dry weight (g hill-1) was taken at the 30 DAT and PI stage. It did not show
any significant difference among the treatments. The maximum total aboveground dry weight,
however, was obtained in the treatment of incorporation of rice straw into the soil combined withthe application of cattle manure at 30 DAT and PI stage (Table 2).
Number of panicle per hill
The number of panicle per hill or per unit area is the most important component of yield. The larger
the number of panicles, the more the yield will be. In the present experiment, incorporation of ricestraw into the soil combined with the application of cattle manure and bio-extracted fertilizer
produced the maximum number of panicle per hill (9.00), but did not show a significant difference
from the incorporation of rice straw into the soil combined with the application of cattle manure(Table 3).
Table 3 Grain yield and yield components of KDML 105 as affected by application of ricestraw, cattle manure and bio-extracted fertilizer in 2009
Treatments

Panicleno./hill

Rice straw
Rice straw + cattle manure
Rice straw + bio-extracted fertilizer
Rice straw + cattle manure+ bio-extracted fertilizer
F-testCV (%)

7.50 b
8.50 a7.50 b
9.00 a*6.60

Filledgrains
(%)
96.90
96.65
97.10
95.78
NS
1.58

1000 grain
weight
(g)
25.24
26.42
25.10
25.34
NS
4.12

Grain yield(kg/ha)3103.13 b
3820.31 a
3239.38 b
3796.88 a*
11.78

Means followed by the same letter at the same column were not significantly different by LSD* significant at P< 0.05 and NS not significant

Fill grain percentage and 1000- grain weight
In the present experiment, rice straw incorporation into the soil alone and combined with variousorganic fertilizers did not show any significant difference in filled grain percentage and 1000-grain
weight (Table 3).

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Grain yield (kg ha-1)
The results showed that grain yield was significantly different among the incorporation of ricestraw into the soil and rice straw combined with various organic fertilizers treatments. The ricestraw incorporated into the soil combined with the application of cattle manure produced maximum
grain yield (3820 kg ha-1) which did not make a significant difference from the treatment of ricestraw incorporated into the soil combined with cattle manure and bio-extracted fertilizer (3797 kgha-1) (Table 3).
Nutrient concentration in leaf
The incorporation of rice straw into the soil alone and incorporation with various organic fertilizers
had no significant effect on N and K, but it did significantly affect the P concentration of theleaves. The incorporation of rice straw into the soil combined with cattle manure gave themaximum P (0.219%) concentration (Table 4).
Nutrient concentration in stem
The incorporation of rice straw into the soil alone and combined with various organic fertilizers hada significant effect on the N, P and K concentration of stem. The incorporation of rice straw into
the soil combined with the application of cattle manure and bio-extracted fertilizer gave maximum
N (0.535%) concentration of the stem. The incorporation of rice straw into the soil combined withapplication of cattle manure obtained the maximum P (0.267%) and K (2.938%) concentration of
the stem (Table 4).
Table 4 Nitrogen, phosphorus and potassium content in leaves and stems of KDML 105 asaffected by application of rice straw, cattle manure and bio-extracted fertilizer atpanicle initiation in 2009
Treatments
Rice straw
Rice straw + cattle manure
Rice straw + bio-extracted fertilizer
Rice straw + cattle manure+ bioextracted fertilizer
F-testCV (%)

N (%)
1.614
1.580
1.603
1.645

Leaf
P (%)
0.165 b0.219 a0.176 b0.212 a

K (%)
2.381
2.514
2.389
2.548

N (%)
0.430 b0.484 a0.500 a0.535 aStem
P (%)
0.193 b0.267 a0.208 b0.259 aK (%)
2.510 b2.938 a2.756 ab2.859 a

NS
2.92

**
2.92

NS
3.56

**
3.72

**
9.41

**
4.73

Means followed by the same letter at the same column were not significantly different by LSD** significant at P< 0.01 and NS not significant

DISCUSSION
The rice straw incorporated into the soil after the rice harvest combined with the application of
cattle manure significantly increased the grain yield over the yields from incorporation of the ricestraw alone. But it did not show any significant increase in the grain yield over the treatment ofincorporation of rice straw into the soil combined with application of cattle manure and bioextracted fertilizer. In general, rice straw provided a higher supply of K, but a lower supply of N
and P than the other organic fertilizers (Javier et al., 2002). At crop maturity, the rice straw has
about 40% of N, 30-35% of P and 80-85% of K (Dobermann and Fairhurst, 2002). In the present
experiment, rice straw provided N, P and K in the soil at 25.7, 6.2 and 47.4 kg ha-1, respectively.
Rice  straw  improves  the  soil’s  physical,  chemical  and  biological  properties  (Mandal  et  al.,  2004).  
In the treatment of incorporation of rice straw into the soil combined with the application of
cattle manure, the rice crop received additional N, P and K from the cattle manure. In the present
experiment, cattle manure provided N, P and K at 103.7, 35.1 and 335.6 kg ha-1, respectively.
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Cattle manure applied to the rice crop increased root density and enhanced root growth to deeper
soil layers (Abe et al., 1995). Cattle manure-P is relatively more mobile than inorganic fertilizer-P
and promotes microbiological activities and P cycling (Parham et al., 2002).
In the present experiment, however, bio-extracted fertilizer combined with cattle manure
application did not show any significant effect on grain yield in comparison with cattle manure
application. This is probably due to the small quantity of N, P and K that bio-extracted fertilizer
provided to the rice crop. The concentration value of N, P and K was about 0.089, 0.014 and0.433%, respectively. This means that the bio-extracted fertilizer provided an additional small
quantity of the nutrients to the rice crop. Kaewtubtim (2008) reported that quantity of macronutrients in soluble bio-extracted fertilizer depends on the sources of materials fermented. He foundan N concentration range of 0.24-0.64%, a P concentration range from 0.2 to 0.62% and a K range
from 0.54 to 2.09% in soluble bio-extracted fertilizer fermented from 6 native fruits.
The sufficient N concentration in leaves at the PI stage was about 2.6-3.2% of dry weight(Mikkelsen and Hunziker, 1971). In this experiment, the N in leaves at PI stage was 1.580-1.645%
of dry weight of all treatments. This indicates that the N in soil was not adequate for plant growthat PI. The N deficiency at PI stage caused a reduction of grain numbers per panicle and filled grain
percentage (Dobermann and Fairhurst, 2000).
The sufficient P concentration value in leaves at the PI stage was about 0.17% of dry weight(Fageria et al., 1988). In the present experiment, P in leaves at PI stage was 0.165-0.219% of dry
weight of all treatments. This indicates that P in soil provided an adequate amount for rice growthat PI. Similarly, in case of K, the sufficient K concentration value in leaves at the PI stage wasabout 1.0-2.2% of dry weight (Jones et al., 1991). In the present study, K in leaves at PI stage was
2.381-2.548% and 1.770-2.017% of dry weight of all treatments. This indicates that K in soil
provided adequate amount for rice growth at PI.
In this study of the growth and yield of organic rice as affected by rice straw and organic
fertilizer it was found that rice straw incorporated into the soil after rice harvest combined withapplication of cattle manure produced maximum grain yield (3820 kg ha-1). It produced an 18.77%
higher yield over the treatment of incorporation of rice straw into the soil alone. However, it did notshow any significant difference from the treatment of incorporation of rice straw into the soil
combined with application of cattle manure and bio-extracted fertilizer. In the present experiment,
number of panicle per hill is the most important component of yield.
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OAE   (2006)   The   survey’s   report   of   major   rice   crop   year   2007/08.   Agricultural   Statistics.   Ministry ofAgriculture and Cooperatives, Thailand.
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