Relative performance of new generation herbicides on weed density, yield and nitrogen, phosphorus uptake behaviour in transplanted rice (Oryza sativa)

Abstract

A study was conducted during the rainy season (kharif) 2001 and 2002 to explore the performance of some new generation herbicides on weed density, yield and N, P uptake pattern in transplanted rice (Oryza sativa L.). An application of pre-emergence herbicide mixture almix + 2,4-dichloro phenoxy acetic acid 15 + 500 g/ha recorded significantly lower weed population of grasses and their dry weight over other herbicidal treatment. Whereas, almix 25 g/ha recorded significantly lower density of sedges and broad-leaf weeds and their dry weight over rest of all treatments. Almix + 2,4-dichloro phenoxy acetic acid 15 + 500 g/ha recorded minimum total weed population and their dry weight and significantly superior to other chemical treatments. This treatment recorded maximum amount of nitrogen and phosphorous concentration in grain and straw and total uptake and significantly better than all other herbicidal treatments, crop could remove 107.33 kg N and 22.58 kg P/ha, which were 143 and 132 % more compared to crop removal under weedy check treatment respectively. Maximum grain (5.83 tonnes/ha) and straw yield (7.13 tonnes/ha) was obtained with almix + 2,4-dichloro phenoxy acetic acid 15 + 500 g/ha and it was at par with hand weeding which had highest grain (5.90 tonnes/ha) and straw yield (7.21 tonnes/ha).