Effects of weed management practices on soil microbial dynamics and yield of cabbage (Brassica oleracea var. capitata L.)

Abstract

A field experiment was to study the effect of different weed management practices on Soil microflora and yield attributes and economics of cabbage. The results indicated that the T7 (weed free) recorded maximum value of plant height and earliest 50% head initiation, head maturity duration and yield attributing characteristics diameter of head, average head weight and head yield. It was followed by T1 [Pendimethalin 38.7 CS 0.7 kg a.i/ha (PE)+1 HW 30 DAT], T2 [Pendimethalin 30 EC 1.5 kg a.i/ha (PE)+1 HW 30 DAT], T6 (HW at 25 & 50 DAT). The number of bacterial, fungi and actinomycetes population was recorded with the treatment T8 (weedy check) compared to rest of the population. No significant difference noticed among the herbicide treatments. Beyond 40 days after application of herbicides and up to harvest, the population increased considerably in each case justifying no long term adverse effect of herbicides on the beneficial soil micro fauna and flora. The bacterial population was adversely affected, followed by fungi and actinomycetes in descending order. But at the time of harvest of the crop, the microbial population attained with all the treatments, the level equal to that of initial level or even more than original level in some treatments. The trend was similar in bacteria, fungi and actinomycetes. It is clear that the effect of herbicides on soil microbes is only temporary. The adverse effects of herbicides were gradually reduced with passage of time and practically, there was no adverse effect of herbicides on soil microbial activities in terms of fungi, bacteria and actinomycetes population after harvest of cabbage. Maximum gross return, net return was obtained with [Pendimethalin 38.7 CS 0.7 kg a.i/ha (PE)+1 HW 30 DAT] compared to rest of treatments.