title: Herbicide options for effective weed management in dry direct-seeded rice under scented rice-wheat rotation of western Indo-Gangetic Plains.
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, duringKharif(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-1reduced yield in both cultivars but in CSR 30 yield reduction was twofold (11.5%) as that of Pusa 1121 (5.2%).
authors.affiliation: Dept. of Crop, Soil, and Environmental Sciences, University of Arkansas, Fayetteville 72701, AR, USA.
authors.forename: Vijay
authors.initials: V
authors.lastname: Singh
authors.affiliation: International Maize and Wheat Improvement Center, NASC complex, New Delhi 110012, India.
authors.forename: Mangi L
authors.initials: ML
authors.lastname: Jat
authors.affiliation: Dept. of Agronomy and Horticulture, University of Nebraska-Lincoln, NE 68583, USA.
authors.forename: Zahoor A
authors.initials: ZA
authors.lastname: Ganie
authors.affiliation: Queensland Alliance for Agriculture and Food Innovation (QAAFI), The University of Queensland, Toowoomba 4350, Australia.
authors.forename: Bhagirath S
authors.initials: BS
authors.lastname: Chauhan
authors.affiliation: International Maize and Wheat Improvement Center, NASC complex, New Delhi 110012, India.
authors.forename: Raj K
authors.initials: RK
authors.lastname: Gupta
keywords: B:C ratio; Crop injury; Dry direct-seeded rice; Herbicides; POST; PRE; Weed management