Impact of drip irrigation on soil biological activity, symbiotic traits and yield in summer mungbean

A field experiment was conducted in the summer seasons to assess the impact of drip irrigation on soil biological activity, symbiotic traits and yield in summer mungbean. Recommended variety of summer mungbean “SML-832” was sown with three drip irrigation treatments viz. 1.0ET_c(I₁), 0.80ET_c(I₂), 0.60ET_c(I₃) along with one controlled flood irrigation treatment (C). Significant difference for number of nodules, nodule dry weight and leghemoglobin content of nodules was observed at flowering stage between drip irrigation and controlled flood irrigation treatments which also had a positive impact on yield. The maximum number of nodules (35.1 plant^-1) nodule dry weight (78.7 mg plant^-1) and grain yield (1154 kg ha^-1) was under drip irrigation at 0.80ET_c. Viable population of soil microbes increased from sowing to flowering stage but decreased at maturity of summer mungbean during both the years. Soil dehydrogenase activity was also maximum under drip irrigation at 0.80ET_c at flowering stage. The overall viable count for bacteria (6.45 log cfu/g), actinomycetes (5.31 log cfu/g) and fungi (4.54 log cfu/g) were higher in drip irrigation at 0.80ET_c while minimum under flood irrigation treatment. The total microbial population and nodulation was higher in 2016 as compared with 2015 due to better initial soil microbial population. Grain yield was positively correlated with dry weight of nodules as well as with soil microbial population. From the study it was concluded that drip irrigation at 0.80 ET_c results in high soil microbial activity with enhancement in symbiotic traits and better crop yield in summer mungbean crop.