Weed growth and nutrient uptake in organically managed rice and maize as affected by nitrogen management and live mulching with cowpea

Field investigations were conducted during 2015 and 2016 kharif seasons at the experimental farm of ICAR, Nagaland Centre, Medziphema to study weed growth and nutrient uptake in organically managed rice and maize as affected by N management and live mulching with cowpea. The experiment was laid out in factorial RBD with two kharif crops viz., rice (C₁) and maize (C₂), two organic N management viz., vermicompost @ 2 t/ha (N₁) and vermicompost @ 2.7 t/ha (N₂) and two mulches viz., control (No mulching) (L₁) and live mulching with cowpea (L₂). The dominant weed species observed were Cynodon dactylon, Digitaria setigera, Ageratum conyzoides, Amaranthus viridis, Cyperus iria and Cyperus rotundus. Weed density, dry weight and NPK uptake was found to be significantly lower in maize compared to rice during both years. Weed growth and NPK uptake was also found to be significantly higher with application of vermicompost @ 2.7 t/ha (N₂) compared to 2 t/ha (N₁) whereas, significantly lower weed growth as well as NPK uptake was also recorded with cowpea live mulch (L₂) as compared to no mulching (L₁). Cowpea live mulch (L₂) with application of vermicompost @ 2 t/ha (N₁) was found to record significantly lower NPK uptake by weeds in both crops. Yield and yield attributes of rice and maize were observed to be higher under cowpea live mulch with application of vermicompost @ 2.7 t/ha (N₂).