EFFECT OF PHOSPHORUS AND WEED MANAGEMENT ON GREENGRAM (PHASEOLUS-RADIATUS) AND ITS RESIDUAL EFFECT ON MUSTARD (BRASSICA-JUNCEA)

A field experiment was conducted during 1989-90 and 1990-91 to study t he influence of phosphorus and weed management on performance of green gram (Phaseolus radiatus L.) and its residual effect on mustard [Brass ica juncea (L.) Czernj. & Cosson]. The phosphorus showed only marginal effect on growth and yield of greengram, but its effect on weeds was spectacular. By and large, 1 weeding resulted in significantly higher dry matter of greengram at 21 days and at maturity, whereas weed-free treatment proved significantly superior to 1 weeding in 1989 only. Wee d-dry matter in favour of no-weeding treatment was about 3 times more compared with 1 weeding in 1989 and 5 times more in 1990. On an averag e 1 weeding gave significantly higher seed yield of greengram than no weeding each year and in 1990; weed-free treatment proved significantl y superior to 1 weeding as it gave significantly higher yield of musta rd over no weeding or 1 weeding in greengram. While there was no varia tion in available N status of soil after experimentation, a continuous increase in available P status of soil was observed with successive i ncrease in level of P.