Effect of mulching on soil environment, microbial floraand growth of potato under field conditions

Abstract

Mulches modify hydrothermal regime, recycles plant nutrients, promote crop development and increase yields. The impact of straw mulch and different doses of recommended nitrogen was studied on soil microbial flora, soil physico-chemical properties and plant growth parameters of potato at different time intervals under field conditions. Maximum bacterial population (75× 107 cfu g-1 soil), plant growth promoting rhizobacteria count (63× 105 cfu g-1 soil) and fungal population (69× 103 cfu g-1 soil) were observed with the treatment having rice straw mulch @ 6 tonnes/ha and 100% N-level while diazotrophic count (42× 105 cfu g-1 soil) was found with treatment having mulch (6t) but no nitrogen fertilizer at 30 DAS. Mulched soil samples gave statistically higher microbial population. The soil pH and the electrical conductivity of soil were not significantly affected by the different applications. A slight improvement in soil organic content was observed in mulched (0.32%) over unmulched (0.24%) soil samples at 90 DAS. The mineral nitrogen content of soil i.e. ammonical (235.2 kg/ha) and nitrate (156.8 k/ha) nitrogen were greatly affected at 90 DAS by mulching and higher doses of nitrogen fertilization. The altered microbial population helps in improving the various growth parameters of potato plants. Maximum chlorophyll content (1.84 mg/g), maximum dry root-shoot biomass (0.7 g/pl and 5.8 g/pl) and maximum yield (366.8 q/ha) were observed with the treatment having mulch and 100% N-level. It is also concluded that mulch increased the minimum soil temperature by 2-30C and lower down the maximum by 2 to 80C.