Effect of agronomic practices on the performance of aerobic rice (Oryza sativa) and associated weeds under Alfisols of eastern dry zone of Karnataka

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An experiment was conducted during the rainy season (kharif) of 2011 and 2012 at Bengaluru, Karnataka to evaluate the effect of integrated package of agro-techniques on weeds and aerobic rice (Oryza sativa L.). The ex- periment was set up in a randomized complete-block design replicated thrice, consisting of 10 treatment combina- tions of recommended dose of fertilizers (RDF), FYM, FeSO and biofertilizers along with pre-emergence herbi- 4 cide pyrazosulfuron ethyl at 25 g a.i./ha alone and with integrated weed-management practices. Along with this, site-specific nutrient management for targeted yield of 6.5 and 7.5 t/ha, respectively, + integrated weed manage- ment practices were also tried. Treatments receiving integrated weed management practices (pre-emergence her- bicide pyrazosulfuron ethyl at 25 g a.i./ha + hand-weeding at 20 days after sowing + first intercultivation 25 days after sowing and subsequent intercultivations at 15 days interval up to panicle-initiation stage) recorded signifi- cantly lower weed population, weed dry weight and nutrient uptake by weeds than pre-emergence application of pyrazosulfuron ethyl alone. Application of RDF + FYM + biofertilizers + FeSO + integrated weed management re- 4 sulted in significantly higher grain and straw yields, water productivity and nutrient uptake (N,P,K, Zn and Fe) by crop than that with RDF + FYM + pyrazosulfuron ethyl at 25 g a.i./ha. Similar trend was also observed for net re- turns and benefit: cost ratio.