Abstract
Farmers' participatory field trials were conducted at Madhuban, and Taraori, the two participatory experimental sites/locations of the Cereal Systems Initiative for South Asia (CSISA), a collaborative project of IRRI and CIMMYT in Karnal district of Haryana, India, during Kharif (wet season) 2010 and 2011. This research aimed to evaluate preemergence (PRE) and postemergence (POST) herbicides for providing feasible and economically viable weed management options to farmers for predominant scented rice varieties. Treatments with pendimethalin PRE fb bispyribac-sodium + azimsulfuron POST had lower weed biomass at 45 days after sowing (DAS). At Madhuban, highest grain yield of scented basmati rice (3.43 t ha−1) was recorded with the sequential application of pendimethalin PRE fb bispyribac-sodium + azimsulfuron POST. However, at Taraori, yields were similar with pendimethalin or oxadiargyl PRE fb bispyribac-sodium and/or azimsulfuron POST. Applying oxadiargyl by mixing with sand onto flooded field was less effective than spray applications in non-flooded field. The benefit-cost ratio of rice crop was higher with herbicide treatments at both sites as compared with the non-treated weed-free check except single PRE and POST applications and sequential application of oxadiargyl PRE fb oxadiargyl PRE. In a separate experiment conducted at Nagla and Taraori sites, scented rice cultivars' ('CSR 30′ and 'Pusa 1121′) tolerance to three rates of azimsulfuron (15, 25, and 35 g ai ha−1) was evaluated over two years (2010 and 2011). CSR 30 (superfine, scented) was more sensitive to higher rates (35 g ai ha−1) of azimsulfuron as compared to Pusa 1121 (fine, scented). Crop injuries were 8 and 28% in case of CSR 30; 5 and 15% in Pusa 1121 when applied with azimsulfuron 25 and 35 g ai ha−1, respectively. Azimsulfuron applied at 35 g ai ha−1 reduced yield in both cultivars but in CSR 30 yield reduction was twofold (11.5%) as that of Pusa 1121 (5.2%).
Highlights
Rice (Oryza sativa) is a major cereal crop and staple food for more than half of the world's population
Azimsulfuron POST was more effective on broadleaved weeds compared to bispyribac-sodium POST
Maximum weed biomass reduction was observed with the sequential application of pendimethalin PRE fb bispyribac-sodium þ azimsulfuron POST at 45 days after seeding (DAS) (Table 5)
Summary
Rice (Oryza sativa) is a major cereal crop and staple food for more than half of the world's population. Rice is predominantly grown by transplanting seedlings into puddled (conventional wet-tillage) soil and kept flooded for most part of the growing season. The puddled soil ensures good crop establishment, weed control with standing water, and reduces deep-percolation losses (Sharma et al, 2003). The conventional method of rice crop establishment requires a large amount of water, labour, and energy, which are gradually becoming scarce and more expensive. Because of high rate of withdrawal of ground water in conventional tillage based puddled transplanted rice, water tables in some areas of North-West Indo-Gangetic Plains (IGP) has been declining by 0.1e1.0 m per year, resulting in increased cost of water pumping (Humphreys et al, 2010; Rodell et al, 2009; Hira, 2009). There is evidence that water scarcity prevails in IGP (Tuong et al, 2005) and labour costs have increased dramatically due to migration of rural labour to cities (Chauhan, 2012) as well as other non-agricultural sectors of rural economy
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
