Feasibility Analysis of Qualifying Slurry Fertilization Based on the Phosphorus Requirement of Potato

With the series of field trails, the feasibility of qualified biogas slurry applied in crop production based on phosphorus demand was discussed in terms of phosphorus levels from pig slurry on potato yield, quality and economic benefit, and soil nutrient content under the balance of N and K content. The results showed that the potato productivity and the ratio of output to input were increased by 10.98%，16.54%, 18.37% and 0.9,1.0,1.3 respectively with the application level of phosphorus provided by slurry of 90, 135, 180 kg/hm² compared with the chemical fertilizer application. However, there was no significant potato yield between the chemical fertilizer treatment and biogas slurry treatments. The reducing sugar content were obviously higher for slurry application with different levels of phosphorus but no significant improvement of crude protein, total soluble sugar, starch were observed in comparison to chemical fertilization. Meanwhile, the highest utilization rate of phosphorus (12.50%) in current season was obtained with the slurry application providing with phosphorus of 90 kg/hm², and the lowest one (6.80%) was the fertilizer treatment. In addition, the slurry application treatments with the phosphorus amount of 90, 135, 180 kg/hm² could significantly increase the content of soil organic matter, available nitrogen and available potassium after planting, especially with the slurry treatment of providing with phosphorus at the rate of 180 kg/hm² could significantly improve available phosphorus concentration of soil. While the fertilizer treatment only obviously increased the content of available nitrogen and potassium after planting. In conclusion, it was feasible to determine amount of biogas slurry based on the potato demand of phosphorus in agriculture production. The appropriate amount of biogas slurry application in potato was 90 kg/hm² with the upper-middle content of soil phosphorus, while the amount should be added at 180 kg/hm² in soil with phosphorus deficiency.