Microbial population dynamics and dehydrogenase activity in response to integrated use of zinc oxide and zinc solubilizers

Abstract

Soil microorganisms play a key role in nutrient transformation, nutrient cycling, organic matter decomposition, water movement and various other processes essential for maintaining soil quality. In view of scanty information, a pot experiment was carried out at the Department of Soil Science and Agricultural Chemistry, Institute of Agricultural Sciences, BHU, Varanasi, UP during kharif, 2018-19 to evaluate the effect of zinc solubilizers in combination with zinc oxide (ZnO) on microbial population dynamics and dehydrogenase activity of soil at 30 DAT, 60 DAT and after harvesting of rice. In this experiment, three different doses of ZnO (Z0=0, Z1=1.85, and Z23.7 mg kg-1) and three types of microbial inoculation, viz. No inoculation (MQ), Enterobacterclocae strain ZnPSBJ-6 (M,) and zinc solubilizing fungi (M0) were employed in various combinations. It has found that at 60 DAT, inoculation of M, resulted in 4.1% and 12.8% increase in soil bacterial count while treated with Z, and Zj, respectively. Whereas, in the case of the fungal count increased by around 40% and 48% at 30 DAT while treated with Z, and Z0, respectively over ZQ. After harvesting, the actinomycetes population increased significantly by 45.5% in Z, treated soil. At 30 DAT, dehydrogenase activity increased significantly in treated soil by 7.3% and 27.3% with increasing level of ZnO, i.e. from Z, to Z0 over Z0