Effect of Organic, Inorganic and Natural Farming Practices on Microbial Activity at Rhizosphere in Cotton and Greengram Intercropping System

A field experiment was conducted during the kharif season 2021-22 at Natural Farming Project plot - E 131, Main Agricultural Research Station, UAS, Dharwad on clayey soils to study the effect of different farming practices and foliar application of different organic liquid manures on soil microbial activity of cotton+ greengram rhizosphere. The results revealed that maximum number of microbial populations viz., Bacteria (18.50, 59.22 and 33.83 ×105 cfu g soil-1 (cfu {colony forming unit}), fungi (4.67, 4.61 and 3.67 ×104 cfu g soil-1), actinomycetes (11.72, 9.61 and7.17 ×103 cfu g soil-1), N2 fixers (12.61, 19.61 and 17.44 ×105 cfu g soil-1) and PSM´S (6.94, 14.83 and 13.11 ×105 cfu g soil-1) at harvest stage of greengram, at 90 DAS and harvest stage of cotton was significantly found in organic farming practices. Among liquid organic manures, foliar application of Jeevamrutha @100 % recorded higher number of bacteria (21.17, 61.67 and 35.83 ×105 cfu g soil-1), fungi (5.17, 6.17 and 5.17 ×104 cfu g soil-1), actinomycetes (12.83, 10.50 and 7.00 ×103 cfu g soil-1), N2 fixers (15.67, 21.33 and 18.50 ×105 cfu g soil-1) and PSM´S (8.50, 17.00 and 15.17 ×105 cfu g soil-1) at harvest stage of green gram, 90 DAS and harvest stage of cotton. When compared with recommended package of practices, foliar application of Jeevamrutha @100 % under organic farming practices recorded higher number of bacteria (26.33, 64.00 and 36.33 ×105 cfu g soil-1), fungi (5.67, 6.67 and 5.67 ×104 cfu g soil-1), actinomycetes (13.67, 11.00 and 8.00 ×103 cfu g soil-1) and PSM´S (9.33, 18.00 and 16.33 ×105 cfu g soil-1) at harvest stage of greengram, at 90 DAS and harvest stage of cotton than all other treatments. Foliar application of vermiwash @ 20% recorded highest N2 fixers (23.67 and19.67 ×105 cfu g soil-1) at 90 DAS and harvest stage of cotton.