Abstract：The livestock wastewater can be reused by biogas slurry irrigation in farmland to solve the problem of subsequent disposal to a certain extent. But the loss of nitrogen and phosphorus will lead to the risk of groundwater pollution after long-term biogas slurry irrigation. In this study, the adsorption and migration behaviors of ammonia nitrogen (NH3-N) and total phosphorus (TP) were investigated by simulated biogas slurry irrigation soil column with different soil media. Illumina MiSeq high-throughput sequencing technology was applied to study the soil microbial α diversity variation before and after biogas slurry irrigation. The results showed that different soil media had different effects on the adsorption capacity of NH3-N and TP. Purple soil had the strongest adsorption capacity of NH3-N and TP while river sand had the weakest adsorption capacity. Two days after biogas slurry irrigation, Purple soil quickly adsorbed NH3-N in the surface and middle soil, while the adsorption of ammonia nitrogen decreases in the bottom soil with time. After biogas slurry irrigation, NH3-N in biogas slurry migrated to -25 cm soil layer in purple soil, and the concentration of NH3-N in leachate was 11.52 mg/L; NH3-N migrated to -45 cm soil layer in river sand, and the concentration of NH3-N was 211.80 mg/L, which had a trend of continuous downward migration. The concentration of TP in leachate of purple soil and sandy loam soil at -35 cm layer was 0.23 mg/L and 1.42 mg/L respectively, which could adsorbed and fixed total phosphorus and prevented phosphorus from migrating downward. Meanwhile, the irrigation of biogas slurry reduced the microbial diversity and abundance, and changes the community structure in purple soil. Shannon index and Chao index of purple soil after biogas slurry irrigation were 5.51 and 112.40, respectively. Proteobacteria was the most abundant and Verrucomicrobia was the least abundant. This study provides a certain theoretical basis for the adsorption and migration process of nitrogen and phosphorus elements in soil after biogas slurry irrigation. The impact of soil microbial diversity is also revealed after biogas slurry irrigation. In addition, the subsequent impact on soil and surrounding environment after biogas slurry irrigation is in favor of further comprehension.
