Weed management through combined application of allelopathic crop water leachates and reduced doses of herbicide in cotton (Gossypium hirsutum L.)

Abstract A field experiment was carried out at Cotton Research Sub Station, Piplan, Mianwali to determine appropriate combination of sorghum and brassica water extracts with reduced doses of paraquat (Gramoxon 20 SL), and pendimethalin (Stomp 330 E) for weed management in cotton. Combination of sorghum and brassica water leachates each at 20 L ha-1 and pendimethalin @ 0.417 kg a. i. ha-1 (1/3 dose) as pre-emergence reduced weed density of horse persulane was statistically alike to the brand dose of pendimethalin at 15, 40 and 60 DAS. The diminution in weed dry weight was also equal at 40 DAS while less at 60 DAS. The weed control with 1/3 dose of paraquat in combination with sorghum and brassica water leachates was equal to the full dose paraquat as directed post-emergence recorded at 60 DAS. The maximum seed cotton yield (2150 kg ha-1) was attained with Allelopathic crop water leachates combined with lower rates pendimethalin, while its brand dose @ 1.25 kg a. i. ha-1 produced lesser seed cotton yield (1850 kg a. i. ha-1). Economic and marginal analysis demonstrated that the treatment T6 was the most economical with highest net benefits of Rs.144297/- and marginal rate of return 3299.28% while T5 and T7 are uneconomical due to higher cost that vary and less net benefits .It can be concluded that combination of sorghum and brassica water leachates with 1/3 dose of pendimethalin as pre-emergence for controlling horse persulane in cotton is reasonable and therefore the herbicide dose can be reduced by 67%.