Effect of diversification and intensification of rice-wheat cropping system on weed dynamics in different vegetable based crop sequences in Nalanda District of South Bihar

Abstract

An experiment was conducted at Nalanda College of Horticulture, Noorsarai, Nalanda during three consecutive years of 2012-13, 2013-14 and 2014-2015 to study weed flora and dynamics in different crop sequences. The experiment was laid down in Randomized Block Design with three replications. There were eight crop sequences have been taken for study. Weed flora of different crops in all three seasons have been counted (m-2). Various observations were recorded on pattern of weed infestation in various crops under different cropping systems at 25 days after sowing/planting. Among all the crop sequences, maize-potato-onion reported highest number of weed population (636 m-2) followed by okra-cauliflower-sponge gourd (599 m-2) and onion-onion-bottle gourd (583 m-2) during first year of investigation. But, in third year, the maize-potato-onion recorded (437), followed by okra-cauliflower-sponge gourd (397 m-2) and onion-onion-bottle gourd (293 m-2). Among weeds Cyperus rotundus was reported major in all crop sequences in all three seasons followed by Coronopus didymus in rabi and Phyllanthus Eclipta and Amaranthus in Kharif and Zaid season. It is concluded that Cyperus rotundus, being perennial is major dominant weed in all the crop sequences, while, Coronopus, Phyllanthus, Eclipta and Amaranthus spp. being annuals can be reduced by growing crop sequences viz., onion-onion-bottlegourd, okra-cauliflower-sponge gourd and okra-cabbage-bottle gourd by inter culture operations.