沼液与有机肥配施条件下氮损失风险的研究

本研究旨在探索沼液、有机肥配施等氮量替代化肥的模式,期望能够在保持产量稳定的前提下,降低稻田氮素损失的风险。本试验以太湖水稻土为研究对象进行盆栽试验,设置了空白对照(CK)、常规化肥(NPK)、100%沼液、75%沼液+25%猪粪有机肥、50%沼液+50%猪粪有机肥和100%猪粪有机肥六个处理,采用密闭室间歇通气法研究了不同生育时期的稻田氨挥发特性,同期测定稻田田面水氮含量,以及全施肥期径流流失量。试验结果显示,在等施氮量条件下,常规化肥处理水稻产量达12 752.70 kg·hm~(-2),其农田氨挥发总量为76.99 kg·hm~(-2),径流氮损失量39.11 kg·hm~(-2);100%沼液施用处理和75%沼液+25%猪粪有机肥配施处理氨挥发量较高,分别为120.66、88.01 kg·hm~(-2);而50%沼液+50%猪粪有机肥配施处理氨挥发总量和径流氮流失量均低于常规化肥处理,分别为58.03、22.00 kg·hm~(-2),其产量与常规化肥处理相比无显著性差异;100%猪粪有机肥施用处理尽管氨挥发总量和径流氮流失量表现最低,但其产量低于50%沼液+50%猪粪有机肥配施处理。综合比较而言,50%沼液+50%猪粪有机肥配合施用处理在保持一定产量的基础上又能减少氨挥发及氮流失风险,是一种比较适宜的施肥模式。

Risk of nitrogen loss under the combined application of biogas slurry and organic fertilizer

The purpose of this study is to explore a model for the combined application of biogas slurry and organic fertilizer instead of chemical nitrogen fertilizer to reduce the risk of nitrogen loss in a paddy field while maintaining a stable yield. A pot experiment was conducted to investigate the characteristics of ammonia volatilization, nitrogen content in surface water, and nitrogen loss in runoff after fertilization during rice growth. The soil from a paddy field in Taihu Lake was used in the experiment. There were six treatments, including a blank control, conventional chemical fertilizer, 100% biogas slurry, 75% biogas slurry + 25% pig manure organic fertilizer, 50% biogas slurry + 50% pig manure organic fertilizer, and 100% pig manure organic fertilizer. The results showed that under the same nitrogen application rate, rice yield in the conventional chemical fertilizer treatment reached 12 752.70 kg·hm^-2, and the total amount of ammonia volatilization and nitrogen loss in runoff was 76.99 kg·hm^-2 and 39.11 kg·hm^-2, respectively. Compared with the conventional chemical fertilizer treatment, the ammonia volatilization was significantly higher in both 100% biogas slurry treatment and 75% biogas slurry + 25% pig manure organic fertilizer treatments, with 120.66 kg·hm^-2 and 88.01 kg·hm^-2, respectively. The total amount of ammonia volatilization (58.03 kg·hm^-2) and runoff nitrogen loss (22.00 kg·hm^-2) in the 50% biogas slurry + 50% pig manure organic fertilizer treatment was significantly lower than that in the conventional chemical fertilizer treatment; however, the rice yield did not differ significantly. The amount of ammonia volatilization and runoff nitrogen loss in 100% pig manure organic fertilizer treatment was the lowest among all treatments; however, the rice yield was lower than that of the 50% biogas slurry + 50% pig manure organic fertilizer treatment. Therefore, 50% biogas slurry + 50% pig manure organic fertilizer is a more appropriate fertilization model, which can reduce the risk of ammonia volatilization and runoff nitrogen loss while maintaining a certain yield.