Abstract: The effects of rural mixed wastewater irrigation treatment (WG) on soil pH, nutrient content, enzyme activity, and microbial diversity were examined in a soil column simulation experiment. Compared with clean water irrigation treatment (CK), WG treatment increased the contents of soil total potassium, total phosphorus, available potassium, and alkalihydrolyzable nitrogen (4.54%-46.84%), while decreased soil pH, the concentrations of organic matter, total nitrogen and available phosphorus (2.02%-32.61%). The activities of soil catalase and acid phosphatase were lower than CK (P<0.01), while the activities of soil urease and invertase were higher than those in CK (P<0.05). The diversity indices (Shannon, Ace, Chao and Coverage) of bacteria and fungi increased in soil, but the Simpson index decreased and the relative abundances of each dominant species of bacteria and fungi at the genus level were changed. The results of evaluation based on Nemerow comprehensive index showed that mixed wastewater irrigation can improve soil fertility. Our results provide the theoretical basis and technical guidance for the field experiment of rural mixed wastewater irrigation model in demonstration area.

Key words: Picea crassifolia forest, community structure, spatial heterogeneity, geostatistics, Qilian Mountains.