Unraveling the impact of long-term monoculture practice on soil fertility: insights from microbial biomass and carbon metabolic rate in a Chinese meadow soil

Agricultural intensification generally deteriorates soil health conditions. We aimed to examine whether and to what extent long-term rice cultivation activities would adversely influence soil physicochemical and microbial characteristics. The research was performed in a seed multiplication farm in Wuchang city of China. We quantified changes in physicochemical indicators and microbial indices (biomass and carbon metabolic characteristic (AWCD)) of soils collected in both cultivated (rhizosphere (RS) and bulk soil (BS)) and uncultivated (US) paddy rice fields from spring to winter. The non-parametric method was used to compare AWCDs of the three types of soil samples. Principal component analysis was employed in distinguishing differences in soil physicochemical indicators and AWCDs, respectively, of the three types of soil. We found that: (1) RS commonly performed well in nutrient-related soil physicochemical indicators. (2) Microbial biomass in US was constantly higher than BS and RS. (3) There was a visible difference in preference of carbon compound groups for the three soil types between summer and other seasons. In conclusion, agricultural activities could reshape soil microbial characteristics. Notably, specific cultivation activity may induce distinct responses of soil microbial parameters. Moreover, soil biological properties respond more sensitively to cultivation practices than traditional physicochemical indicators.