Characteristics of purple vegetable soil under biogas slurry irrigation

Biogas slurry irrigation at Mountain town in the reservoir area of Three Gorges was demanded not only by taking full advantage of dung resources, but also not destroying the growth of plants and soil environment. This research used the wastewater from a dairy farm in the southwest, including grit chamber wastewater (GCW), collection basin wastewater (CBW), anaerobic tank wastewater (ATW), aerobic effluent (AE) and clean water (CW) for parallel irrigation in the greenhouse. The experiments indicated that ATW contained the maximum ammonia nitrogen content of 860 mg / kg in 0-5 cm soil profile sample. In 0-5 cm soil profile samples, the content of nitrate nitrogen in ATW remained the highest with 23.95mg / kg. In 5-10 cm and 10-20 cm soil profile samples, the nitrate nitrogen content of the other four test groups increased and reached the final value of 23.67 mg/kg. In 0-5 cm from soil surface the phosphorus content of the five groups were less than 100 mg/kg. The phosphorus absorption coefficient of CW reached a peak value of 570 after half a month. And the maximum content of ammonium nitrogen, nitrate, and available phosphorus were 1355 mg/kg, 24.65 mg/kg, and 163.66 mg/kg respectively. The phosphorus absorption coefficient in the 5th to 9th day was more than 500. According to the research of different irrigation water quality contrasting, nitrogen and phosphorus accumulation and adsorption, soil bearing capacity test, the load of biogas slurry irrigation provides references to further the reasonable irrigation and the actual operation.