| 【Objective】The study was carried out to explore the impact of biogas slurry application on soil environmental quality in intensive livestock and poultry farms for reasonable application of biogas slurry to promote the development of combined planting and breeding of circular agriculture and protect the agricultural ecological environment.【Method】The soils with continuous application of biogas slurry for 4, 5, 8 and 10 years were collected, and the contents of soil mechanical stablility aggregates and water-stable aggregates, soil alkaline nitrogen, available phosphorus, organic matter and heavy metals were determined, respectively. And the relationship between long-term application of biogas slurry and soil aggregates, nutrient contents and heavy metals were studied.【Result】The application of biogas slurry significantly increased the contents of soil mechanical stablility aggregates ( ＞ 2 mm) and water-stable aggregates, among which the content of water-stable large aggregates increased by 19.50% when the biogas slurry was applied for 10 years. With continuous application of biogas slurry for 10 years, soil aggregate stability indicators MWD, GMD, R0.25 increased,and soil aggregate stability was significantly improved. The application of biogas slurry could significantly increase the organic matter of soil aggregates ( ＞ 2 mm and 0.5~2 mm), with an increase of 28.11%-522.42%. Different application years of biogas slurry could increase the contents of soil alkaline nitrogen, available phosphorus and organic matter, with the maximum increases of 93.86%, 121.96% and 138.46% respectively, which effectively improved soil fertility supply capacity. Long-term application of biogas slurry may cause obvious accumulation of soil Zn and Cu, which results in a risk of soil pollution.【Conclusion】Continuous application of biogas slurry can increase the contents of soil macroaggregate, aggregate organic matter, soil alkaline nitrogen, available phosphorus and heavy metals. While increasing soil fertility and soil aggregate stability, there is a risk of accumulation of heavy metals, and heavy metal control measures shall be taken for long-term use of biogas slurry. |
