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999			_c141179 _d141179
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082			_a630 _bRES/EF
100			_aReshma R S
245			_aEfficacy and economics of weed management strategies in aerobic rice (Oryza sativa L.)
260			_aVellayani _bDepartment of Agronomy, College of Agriculture _c2014
300			_a120p.
502			_aMSc
520	3		_aThe experiment entitled “Efficacy and economics of weed management strategies in aerobic rice (Oryza sativa L.)” was undertaken at the Instructional Farm, College of Agriculture, Vellayani, Thiruvanthapuram, during January, 2013 to May, 2014. The main objectives of the study were to assess the extent of yield loss due to weeds in aerobic rice, to assess the most suitable weed management strategy for aerobic rice and to study the economic feasibility. The field experiment, laid out in randomised block design, comprised seven weed management practices (variety – Aiswarya) compared against a control (variety – MAS 946-1), replicated thrice. The treatments were W1: hand weeding (HW) at 15, 30 and 45 DAS (days after sowing) ,W2 : mechanical weeding, W3 : mechanical weeding with power weeder, W4 : mulching with straw @ 4 t ha-1,W5 : oxyfluorfen @ 0.15 kg a.i ha-1 + HW at 20 DAS, W6 : pretilachlor @ 0.75 kg a.i ha-1 + HW at 20 DAS, W7 : weedy check and Control (C): MAS 946 – 1, maintained weed-free by HW at 15, 30 and 45 DAS. The results of the study were as follows: The treatment, W5 (oxyfluorfen @ 0.15 kg a.i ha-1 + hand weeding at 20 DAS) was superior or equally effective as W1 (hand weeding 15, 30, 45 DAS) with respect to growth attributes and dry matter production of rice. Yield attributes were significantly superior at W5 (oxyfluorfen @ 0.15 kg a.i ha-1 + hand weeding at 20 DAS). Grain yield was maximum (3889 kg ha-1) with W1 (hand weeding 15, 30, 45 DAS) and remained at par (3500 kg ha-1) with W5. Harvest index also was highest for W1 and remained at par with W5. In general, broad leaved weeds were more, compared to grasses and sedges. The total weed density, weed dry matter production and nutrient removal by weeds were lesser at W5, which recorded the highest weed control efficiency. The net income and benefit cost ratio of Aiswarya (1.62) was significantly higher at W5. The treatments when compared against control, revealed the superiority of the aerobic rice variety MAS 946-1 with significantly higher tiller count, grain yield and net income. Considering the growth, yield attributes, yield and economics, the pre-emergence application of oxyfluorfen @ 0.15 kg a.i ha-1 followed by hand weeding at 20 DAS was effective in managing the weed problem in rice (variety Aiswarya) raised under aerobic condition.
650			_aAgronomy
700			_aShalini Pillai P (Guide)
856			_uhttp://krishikosh.egranth.ac.in/handle/1/5810025971
942			_2ddc _cTH