Weed Dynamics in Greengram as Influenced by Mulching and Weed Management Practices under Eight Year Old Custard Apple Plantation in Agri-horticultural System

An experiment was conducted at Agronomy Research Station, Barkacha, Mirjapur 2013-14 in order to control greengram associated weed under Custard apple plantation during Kharif season. The basic objective of the study was to assess the effect of mulching and weed management practices on weed dynamics and greengram yield under agri- horticultural system. Three mulch treatments taken in main plots (no-mulching, dust-mulching and paddy straw-mulching) and five weed control treatments (weedy check, weed free, pendimethalin pre-emergence (PE) 1000 g ha-1, imazethapyr post-emergence (PoE) 100 g ha-1 and pendimethalin (PE) 1000 g ha-1+ imazethapyr (PoE) 100 g ha-1) was randomly allocated to subplots and these were replicated thrice in split plot design on sandy clay loam soils with pH 6.2. The various weeds observed in greengram field were Cyperus rotundus, Echinochloa colona, Cynodon dactylon and Erogrostis pilosa. Among the grasses, Echinochloa colona, in broad leaved weed Erogrostis pilosa and in the sedges Cyperus rotundus was predominant. Dust mulching recorded significantly the highest grain yield (747 kg ha-1), straw yield (1797 kg ha-1) and lowest weed index (1.44%), density and dry weight of Cyperus rotundus, Echinochloa colona, Cynodon dactylon and Erogrostis pilosa, as well as total density and dry weight of weeds over paddy straw mulching. Among herbicidal treatments, sequential application of pendimethalin (1000 g ha-1, PE) + imazethapyr (100 g ha-1, PoE) resulted lower density and dry weight of Cyperus rotundus, Echinochloa colona, Cynodon dactylon and Erogrostis pilosa as well as total density and dry weight of weeds, and recorded significantly highest grain yield (726 kg ha-1) and straw yield (1726 kg ha-1) with minimum weed index (4.15%) followed by same was with the alone application of pendimethalin and imazethapyr, respectively. Weed control efficiency and the regression of yield on it revealed that 1% increase in the weed control efficiency increased the grain yield by 1.873 kg ha-1 and in the straw yield by 2.085 kg ha-1. It is concluded that dust mulching and sequential application of pendimethalin (1000 g ha-1, PE) + imazethapyr (100 g ha-1, PoE) resulted significantly the highest grain and straw yield; and lowest weed index (1.44%), density and dry weight of weeds over other weed management treatments.