Functional Diversity of Soil Microbes Influenced by Long Term Contrasting Tillage, Nitrogen Level and Cropping System

Tillage and fertilizer level modify physico-chemical environment of soil and thus may affect functional diversity and ecosystem services mediated by soil microbes. In this experiment, the functional diversity of soil microbes under two contrasting tillage i.e. No tillage (NT) vs Conventional tillage (CT), two cropping system i.e. Maize-wheat (MW) vs Maize-chickpea (MC) at two N level i.e. 0 vs 100% of recommended dose was studied using community level physiological profiling after nine years of imposing treatments. The highest average well color development (AWCD) was observed in CT—100% N followed by NT—100% N. Mean AWCD was 7.7% higher in MW compared to MC system, 17.8% higher in CT than NT and 21.8% higher at 100% N than 0% N. Mean AWCD of tillage and N level was higher in CT—100% N than NT—100% N and lowest in NT—0% N. Although, with increase in N level AWCD increased, functional diversity of soil microbes was higher at lower 0% N level compared to 100% N level. The mean value of Shannon diversity index in MC system was (3.374) which was significantly higher than MW (3.35) system, while diversity at lower fertilizer dose 0% N was higher (3.377) than 100% N (3.347). Despite higher AWCD in CT-MW, the functional diversity was more in NT-MC and higher at 0% N than 100% N. The study indicated that CT and optimum N encouraged utilization of specific carbon substrate to higher extent in MW system whereas NT and N limitation promoted utilization of a greater number of substrate and increased functional diversity in MC system.