Effect of irrigation schedule and weed-management practices on productivity and profitability of direct-seeded rice (Oryza sativa) in South-eastern Rajasthan

A field experiment was carried out at Agricultural Research Station, Kota, Rajasthan during the rainy (Kharif) season of 2011 and 2012, to evaluate the productivity and profitability of rice (Oryza sativa L.) grown under directseeded condition as influenced by irrigation scheduling and weed-management practices in South-eastern Rajasthan. Treatments comparised irrigation schedules in main plots, viz. 75, 100 and 150% cumulative pan evaporation (CPE), and weed-management practices in sub-plots, viz. pendimethalin @ 1.0 kg/ha, bispyribac sodium @ 35 g/ha, pendimethalin @ 1.0 kg/ha followed by (fb) bispyribac sodium @ 35 g/ha, brown manuring + 2, 4-D @ 0.8 kg/ha and weedy check, was laid out in split-plot design with 3 replications. The pooled data of 2 years revealed that application of irrigation at 100% CPE resulted in significantly higher plant height and dry-matter accumulation at harvest, tillers/m2, panicle length and weight, filled spikelets/panicle, test weight, dry weight of weeds at harvest, N, P and K uptake by weeds at harvest, grain and straw yield, net returns and benefit: cost ratio, water-use efficiency (WUE) and water productivity than irrigation at 75% CPE. However, plant height and dry-matter accumulation were maximum at harvest with the irrigation at 150% CPE. Among weed-management practices, pre-emergence application of pendimethalin @1.0 kg/ha fb bispyribac sodium @ 35 g/ha showed the highest growth and yield attributes, yields, net returns, benefit: cost ratio, WUE and water productivity, weed-control efficiency (WCE) and low NPK uptake by weeds at 45 days after sowing (DAS) and at harvest.