Soil microbial load as affected by crop geometry and weed management practices in Rabi sweet corn under sweet corn-greengram system in Alfisols of Odisha

Abstract

A two years field experiment was conducted at the Odisha University of Agriculture and Technology, Bhubaneswar, Odisha, India during 2021-22 and 2022-23 following a split-plot design comprising of three plant geometries namely, 40 cm x 20 cm (P1), 50 cm x 20 cm (P2), and 60 cm x 20 cm (P3) as main plot treatments and six weed management treatments as subplots namely; Live mulch with cowpea up to 30 days after sowing (DAS) (W1); Live mulch with cowpea up to 45 DAS (W2); Pendimethalin @ 0.75 kg a.i./ ha (W3); Farmers’ practice (W4); Weed free check (W5); and Weedy check (W6) which were replicated thrice. Soil samples were collected from 0-15 cm depth at different stages of growth of sweet corn in order to analyze soil microbial load of bacteria, fungi, and actinomycetes so as to investigate the effect of crop geometry and weed management practices on soil microbial populations. Experimental results revealed that there was no significant effect of crop geometries on microbial populations. However, weed management practices significantly influenced soil microbial load of bacteria, fungi, and actinomycetes after initial 0 DAS. At 15, 30, 45 DAS and at harvest, it was found that Pendimethalin @ 0.75 kg a.i./ ha (W3) resulted in significantly lowest microbial populations while live mulch with cowpea up to 45 DAS (W2) exhibited significantly highest results during both the experimental years. All microbial groups exhibited a typical growth pattern, reaching a peak rate of growth followed by a declining rate was observed. The results of the study emphasized the importance of sustainable weed management practices, particularly cowpea live mulching, in promoting microbial load of soil and improving soil biology in sweet corn-greengram cropping systems.