Effect of changes in soil moisture on agriculture soils: response of microbial community, enzymatic and physiological diversity

Global warming-induced drought stress and the duration of changes in soil moisture content may reshape or complicate these ecological relations. Biological activity could be affected severely by the impact of drought on agricultural ecosystems. In this study, 4 agricultural different soils were collected, and analyzed at each time gradient (0, 1, 2, 4, 8th week) to determine the physicochemical parameters, microbial abundance, enzyme activities (dehydrogenases (DH), phosphatases (acid ACP and alkaline ALP) and urease (UR)), and physiological diversity. We found that soil physicochemical properties fluctuated within the time gradient in all sites, but significantly decreased in total organic carbon, available phosphorus (P2O5 Olsena), nitrate (NO3-), ammonium (NH4+) (except for S site) and calcium carbonate (CaCO3) content (except for L site). Overall, ALP activity was higher compared to ACP activity. The DH activity was highest at sampling day (high moisture content) in G and N sites, and at 2nd week for L and S sites, but significantly decreased at the end of the experiment. The UR activity decreased significantly in G, L and N sites but increased in S site at the end of our experiment compared to the sampling day. Overall, the physiological diversity of the microbial community was strongly affected by water stress in the utilization of carbohydrates, carboxylic and acetic acids, amino acids, polymers, and amines, in all sites. Our findings highlighted that the short-term duration of drought stress had a significant influence on soil biological activity. This may improve the understanding of impact of soil moisture changes on soil nutrient cycling and biological activities in agricultural ecosystems.