Effect of puddling on rice soil physics softness of puddled and percolation. In:
Murty ... Aggarwal, G.C, Sidhu, A.S, Sekhon, N.K. Sandhu, K.S. and Sur, H.S.
1995.
Water Productivity Under Different Puddling Intensities And Organic Amendments in SRI Method Of Rice Establishment 1
1
VEENA SHARMA AND J.PRABHAKARA Sher-e-Kashmir University of Agricultural Sciences and Technology-Jammu, J&K,180009, India
Sher-e-Kashmir University of Agricultural Sciences and Technology-Jammu
ABSTRACT A field experiment was carried for three Kharif and two intervening Rabi seasons, beginning with Kharif 2006 at WMRC research farm of SKUAST Jammu on clay loam soil, to analyze the influence of puddling intensities and organic amendments on water productivity of rice crop and its residual effect on wheat in rice wheat cropping system. Water productivity of rice achieved as a consequence of incident rainfall and applied differential irrigation in C1,C2 (Conventional transplanting of 25-day old seedlings, two per hill, at spacing of 20cm x 15cm, with inorganic fertilizers of N:P2O5:K2O= 30:20:15 kgha -1and 3 t ha-1 FYM respectively, with 7cm depth of irrigations at 8-day frequency) and S1, S2 (SRI transplanting of 10-day old seedlings, one per hill, 25cm x 25cm spacing, with 3 t ha-1 of FYM and wheat Bhusa respectively, with 5cm irrigation at 8 day frequency or less) monitored at 3 week intervals throughout rice growth seasons of Kharif 2006 and 2007 revealed that water productivity was significantly higher in conventionally transplanted plots without organic amendments (C1) than the other treatments (C2,S1,S2), all receiving organic sources of nutrients during the first season. But in the next two Kharif seasons, there was higher water productivity was achieved in SRI plots (S1,S2) as compared to conventionally transplanted plots (C1,C2). There was neither any residual influence of puddling intensities, nor of methods of rice establishment nor of organic additions to soil during rice crop on the grain yield of succeeding wheat crop. Irrespective of differential inputs of water, the soil water content in the preponderant rice rhizosphere has remained at >50% of plant available range, throughout the crop period. There has not been any influence of either puddling levels or organic addition on this uniform moisture status. Similarly, soil water status monitored in Rabi season (2006-07, 2007-08) revealed that soil water status was again in upper half of the plant available moisture range throughout the crop season in all treatment plots. Key words: System of Rice Intensification, Puddling intensity, organic amendments, conventional transplanting, water productivity INTRODUCTION In most of the south Asia, common practice of establishing rice in the rice wheat system is puddling. Puddling helps in reducing water losses through percolationand controlling
weeds in rice fields (Adachi, 1992). But besides being costly, cumbersome and time consuming, it results in degradation of soil and other natural resources and subsequently poses difficulties in seedbed preparation for succeeding wheat crop in rotation. High puddling intensity, however, enhances the development of hard pans and has detrimental effects on the growth and yield of succeeding wheat crops (Aggarwalet al., 1995). In addition there has been deterioration in soil physical conditions (Kukal and Aggarwal, 2003) and resultant reductions in wheat yields following rice (Gill and Aulakh 1990). This decrease in wheat yield may be due to the reduction in root growth and distribution in a poor soil physical environment. Ishaqet al.,2001. Natural structural regeneration of puddled soils is generally slow. Uses of organic amendments, such as FYM, compost, plant residue etc., are known to improve soil physical properties of puddled soils (Bhagat and Verma, 1991). Traditional transplanted rice with continuous standing water has relatively high water inputs. Because of increasing water scarcity, there is a need to develop alternative systems that require less water. Recently , the system of rice intensification ( SRI) has been introduced in irrigated lowland rice in order to reduce the amount of water used for irrigation and negate the impact of puddling on the succeeding crop ( e.g. wheat) ( Uphoff, 2003). The SRI advocates a combination of management practices e.g.use of organic manures, reduction of age and planting density, avoiding anaerobic condition during vegetative phaseetc., which helps in maintaining the system productivity as well as sustainability. Although a few studies have been conducted on water productivity under SRI, very limited information is available on the residual impact of this system on succeeding crop. Therefore in present study the comparative performance of SRI and rice production with conventional method with continuous standing water in respect of water productivity in rice and succeeding wheat crop was evaluated. MATERIALS AND METHODS Field experiment on rice (Basmati-370) was conducted on clay loam soil of Chatha, Research Farm, SKUAST-Jammu located at 740 58´ E, 320 40´ N and 295m above msl under rice-wheat cropping system for the past 5-6 decades under tube-well irrigation. The physico-chemical characteristics of study soil are shown in Table 1. Long term (32-year) mean annual rainfall is 1236 mm and mean seasonal rainfall of kharifand Rabi are 827mm and 288mm respectively. The experimental layout in strip-plot design with five replications consisted of four treatments of puddling intensities in the main plots (strips): Zero puddling (P1) – wet ploughing through one pass of 11-tyne tiller. Conventional puddling (P2) – wet ploughing through two passes of tiller followed by two planking, Medium puddling (P3) two passes of 8-ft Agriking Paddy puddler followed by 2 planking and Thorough puddling (P4) - four passes of 8-ft Agriking Paddy puddler followed by 2 planking. In the sub-plots, the four treatment combinations of methods of rice establishment and organic additions were applied: C1, C2= Conventional transplanting of 25-day old seedlings, two per hill, at spacing of 20cm x 15cm, with inorganic fertilizers of N:P2O5 :K2O= 30:20:15 and 3 t ha-
1
FYM respectively. with 7cm depth of irrigations at 8-day frequency; S1, S2 = SRI transplanting of 10-day old seedlings, one per hill, 25cm x 25cm spacing, with 3 t ha-1 of FYM and wheat Bhusa respectively, with 5cm irrigation at 8 day frequency. Soil water content in 0-20 depth was determined gravimetrically 48 hours after termination of infiltration of added irrigation water by taking samples Field capacity by field method (Coleman, 1944) and permanent wilting point (PWP) by pot method were determined. Then the plant available water was computed using the information on field capacity and permanent wilting point (Table 2).The basic reason for choice of 3000 kg ha-1 of farm yard manure in sub plots S1& C2 is to match the basal dose of N for the cultivar viz. 15 kg N ha-1 in C1 plots (control). Based on the analysis of farm yard manure, inorganic fertilizers applied in C1 plots were corrected to 30:20:15. 50% N andfull P & K as basal dose and balance N in two equal splits at tillering and panicle initiation stages of rice. Table1: Physico-chemical characteristics of soil at the experimental site Soil depth
Sand (%)
Silt (%)
Clay (%)
International pipette method (Day, 1965)
pH
EC (dSm-1)
Organic carbon
Potentiometry (Jackson, 1973)
Conductimetry (Jackson, 1973)
Rapid titration method (Walkley& Black, 1934)
0-20 cm
32
34
34
7.62
0.029
0.58
20-40 cm
30
28
42
7.81
0.027
0.41
Table2: Bulk density, Field capacity, Permanent wilting point and available water range Soil depth
Bulk density (Mg m-3)
0-10
1.54
10-20
1.56
20-30
1.66
Field capacity
Permanent wilting point
Available water range (cm)
% w/w
%v/v
%w/w
%v/v
26.0
40.3
7.8
12.1
28.2
27.0
43.5
7.5
12.1
31.4
30-40
1.56
Volumetric water content in (0-20) cm layer at 50% available water = 26.2% Volumetric water content in (20-40) cm layer at 50% available water = 27.8%
The water productivity of rice crop (kg m-3) was computed on the basis of total water input to the crop yield in each season as Water productivity (kg m -3) = Grain yield in kg ha-1 Total water consumed in m3 ha-1
RESULTS AND DISCUSSION During Kharif2006, total rainfall during rice growth period was 820mm (occurring on 27 rainy days), necessitating application of 8 & 9 irrigations in SRI (S1, S2) and conventional (C1, C2) plots respectively. Total rainfall during the entire rice growth period during Kharif 2007 was 744.6 mm (in 32 days), leading to application of 10 and 12 irrigations in S1,S2 plots and C1, C2 plots respectively. During the first season, significantly higher water productivity of 0.1855 kg m -3was achieved in conventionally transplanted plots without organic amendments (C1) than the other treatments (C2,S1,S2), all receiving organic sources of nutrients (Table 3). Table 3: Water productivity (kg m-3) of rice as influenced by puddling intensities and treatment combinations of rice establishment methods and organic amendments, Kharif2006
Treatments S1 S2 C1 C2 P i –Mean CD5%
P1 0.1191 0.1223 0.1363 0.1556 0.1333 S/C Pi x P i S/C
P2 0.1233 0.1401 0.1535 0.1666 0.1459 0.0212 NS NS
P3 0.1758 0.1680 0.2216 0.2141 0.1433
P4 0.1395 0.1334 0.1528 0.1476 0.1543 CVa CVb
S/C Mean 0.1400 0.1396 0.1855 0.1522 21.36% 20.29%
But in the next two Kharifseasons, there was higher water productivity achieved in SRI plots(S1,S2) as compared to conventionally transplanted plots (C1,C2), although they were all statistically on par with each other (Tables 4 and Tables 5). During all the three seasons, influence of puddling intensities as well as interaction effect of treatments (P i x S/C) on Table 4: Water productivity (kg m-3) of rice as influenced by puddling intensities and treatment combinations of rice establishment methods and organic amendments, Kharif2007
Treatments S1 S2 C1 C2 P i –Mean CD5%
P1 0.2009 0.1829 0.1619 0.1747 0.1801 S/C Pi Pi x S/C
P2 0.184 0.1935 0.1898 0.1872 0.1886 NS NS NS
P3 0.1692 0.2009 0.1802 0.1559 0.1766
P4 0.184 0.1749 0.1811 0.1875 0.1818 CVa CVb
S/C Mean 0.1845 0.1881 0.1782 0.1763 19.93% 15.47%
water productivity in rice were statistically non-significant. It is seen that there was neither any residual influence of puddling intensities, nor of methods of rice establishment nor of organic Table 5: Water productivity (kgm-3) of rice cult. Basmati-370 as influenced by puddling intensities and treatment combinations of establishment and organic amendment, Kharif2008
Treatments S1 S2 C1 C2 Pi –Mean CD5%
P1 0.1887 0.1797 0.1791 0.1676 0.1788 S/C Pi P i x S/C
P2 0.2075 0.1866 0.208 0.1862 0.1971 NS NS NS
P3 0.2187 0.225 0.1826 0.1609 0.1968
P4 0.2046 0.1814 0.1800 0.2016 0.1979 CVa CVb
S/C Mean 0.2049 0.1932 0.1874 0.1791 17.00% 15.65%
additions to soil during rice crop on the grain yield of succeeding wheat crop during both the years of investigation. Similar results were obtained by Choudhuryet al., 2007. Water productivity of wheat was not computed, as there was no differential irrigation input made to the test crop. Wheat crop was grown only to assess the residual effects of treatments imposed on previous Kharif rice on wheat grain yield. There were no residual effects of either puddling intensities or organic additions or methods of rice establishment affected during Kharif on the grain yields of succeeding wheat during Rabi 2006-07 and 2007-08 (Tables 6&7).There were no residual effects of either puddling intensities or organic additions or methods of rice establishment affected during Kharif on the grain yields. Similar results were obtained by Parihar, 2003. The very good (4.2 t ha-1) and good (3.3 t ha-1) grain yields during the two seasons were a function of efficient rain-water management. Table 6: Residual effects of puddling intensities, methods of rice establishment and organic amendments on grain yield (kg ha-1) of succeeding wheat, Rabi 2006-07 Treatments
P1
P2
P3
P4
S/C Mean
S1
4220
4170
4257
3850
4124
S2 C1 C2 P i –Mean CD5%
4114 4375 4227 4284 S/C Pi P i x S/C
4241 4084 4413 4227 NS NS NS
3962 4144 3805 4042
4137 4117 4177 4070 CVa CVb
4114 4180 4203 13.47% 13.39%
Table 7: Residual effects of puddling intensities, methods of rice establishment and organic amendments on grain yield (kg ha-1) of succeeding wheat, Rabi 2007-08 Treatments S1 S2
P1 3074 3182
P2 2918 3482
P3 3132 3164
P4 2889 3202
S/C Mean 3003 3258
C1 C2 P i –Mean CD5%
3792 3484 3383 S/C Pi P i x S/C
2988 3518 3227 NS NS NS
3180 3397 3218
3251 3201 3136 CVa CVb
3303 3400 14.90% 17.08%
Additional organic amendments during rice under SRI methods add to the congenial aerobic environment during rice carried over to wheat. Organic sources of nutrients applied to the preceding crop benefits the succeeding crop to a great extent. This also suggested thatrequirement of very fine pulverized soil by thorough land preparation is not an essentiality for good wheat crop establishment.
CONCLUSION In terms of judicious management of available water resources, irrigation applications have to be tailored only to supplement the incident rainfall, to the extent it is necessary and sufficient to meet the crop water demand and inevitable losses through seepage & percolation. The new system of rice intensification (SRI) method of aerobic cultivation of rice, needing only 5 cm depth of irrigation has a potential of saving irrigation water.In terms on water economy, SRI method has an edge over conventional method of transplanting; but, in order to surmise/notice the positive, synergistic impact of aerobic rice culture of SRI method, it takes two to three seasons. The present study clearly supports the case of popularizing SRI method of rice cultivation to achieve higher water use efficiency,
There is no need of soil puddling as a pre-requisite for establishment of rice on the clay loam soils of sub-tropical plains. Present study reveals that non-availability of FYM/compost in desired quantity for small farmers should not be a matter of concern. Even 3 t ha-1 of wheat bhusa spread on the fields non-retrievably due to heavy winds at wheat threshing stage, if incorporated into soil, would also create the same desirable soil physical environment for the next rice crop, if planned under SRI method.
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