Effect of supplemental irrigation and cotton based intercropping systems on weed control and cotton equivalent yield under rainfed condition

Abstract

A field trial was conducted in farmer’s field to evaluate the supplemental irrigation of cotton based intercropping system on weed dynamics under rainfed Vertisols during Kharif season of 2018-19. The treatments in vertical strip plot includes no supplemental irrigation (SI0) (rainfed), supplemental irrigation at vegetative stage (SI1), supplemental irrigation at squaring to peak flowering stage (SI2), supplemental irrigation at boll formation stage (SI3), supplemental irrigation at above mentioned all stages of cotton (SI4) and supplemental irrigation at wilting symptom appearance (SI5). Horizontal strip includes cotton alone (IC0), cotton + blackgram (1:3) (IC1), cotton + clusterbean (1:3) (IC2) and cotton + coriander (1:4) (IC3). Depending on the time of irrigation, the cotton equivalent yield, weed density and weed dry weight differed among supplemental irrigation treatments. But, lower value of cotton equivalent yield, weed density and dry weight was observed in control (No supplemental irrigation). Higher value of cotton equivalent yield, weed density was observed in supplemental irrigation at wilting symptom appearance. Lower weed density and weed dry weight was recorded in cotton + clusterbean (1:3) at 30 DAS and 60 DAS. Increase in plant population and canopy coverage caused increased weed smothering in cotton + clusterbean (1:3) by 25.3 to 39.5 per cent.