Effect of different components of SRI on yield, quality, nutrient accumulation and economics of rice (Oryza sativa) in tarai belt of northern India
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A field experiment was conducted on a Typic Hapludoll soil in Indo-gangetic plains of India during the 2008 and 2009 rainy seasons to find out the effect of irrigation schedules and plant spacing on yield, quality, nutrient uptake and economics of two rice (Oryza sativa L.) varieties under system of rice intensification (SRI) and compare the performance of SRI with conventional transplanting. Treatments under SRI included 12 combinations of 3 irrigation schedules, viz. irrigation at 1, 3 and 5 day(s) after disappearance of standing water (DADSW), 2 spacings (20 cm × 20 cm, 25 cm × 25 cm) and 2 varieties (‘Pant Dhan 4’, ‘Arize 6444’), alongwith two control treatments of conventional cultivation of each variety. The experiment was set in a RBD with three replications. Irrigation at 1 and 3 DADSW increased uptake of N, P and K in grains, which enhanced grain protein content and milling percentage, and improved grain yield by 8.6 and 5.9% over 5 DADSW (5.82 t/ha), respectively. Net returns and B:C ratio were also better with irrigation at 1 and 3 DADSW. Wider spacing resulted in 4.2% higher yield with better grain quality and 10.8% higher net returns over closer spacing. Yield-wise and profit-wise, both the varieties were suitable for cultivation under SRI. However, ‘Arize 6444’ recorded higher N uptake and protein content. The uptake of P and K was higher in grains of ‘Pant Dhan 4’ which showed higher milling percentage. Between two methods, SRI improved N, P and K uptake, milling percentage and protein content. Grain yield was 16.9% higher under SRI compared to conventional method (5.22 t/ha). Due to lower cost of production and higher yields, SRI fetched 56% higher net returns over conventional transplanting.
Conventional transplanted rice, Irrigation schedule, Milling quality, Nutrient uptake, Spacing, System of rice intensification, Varieties.