秋闲期沼液施用对黑土区土壤氮素损失的影响

为探讨非种植期施用沼液的可行性，采用喷施加深翻及注施方式于2018年10月和2019年10月将不同氮素替代量的沼液施于东北黑土中，研究了黑土区作物收割后（秋闲期）沼液施用对玉米土壤有机质含量的影响，考察了黑土区玉米土壤铵态氮挥发和铵态氮及硝态氮淋溶特性。结果表明：沼液施用能够增加土壤有机质含量，注施沼液对土壤有机质的升高幅度要高于喷施处理。秋闲期在低温条件下以喷施加深翻的方式施用沼液能够减少土壤氨挥发量。秋闲期当喷施氮素替代量在135 kg·hm^-2·d^-1以下时可以施用沼液，此时未发生铵态氮和硝态氮淋溶风险，而采用注施方式时，即使沼液氮素替代量为90 kg·hm^-2·d^-1时仍有潜在发生铵态氮淋溶的风险。两年试验结果初步表明，黑土区秋闲期采用合理的氮素替代量及施用方式施用沼液是可行的。

Effects of biogas slurry application on nitrogen loss soil in black soil area during the autumn fallow period

To explore the feasibility of applying biogas slurry during the non-planting period, different amounts of biogas slurry with different amount of nitrogen replacement were applied via spraying with deep turning and injection to the black soil of northeast China in October 2018 and October 2019. In addition, the effect of applying biogas slurry on the organic matter content of maize soil in the black soil area was investigated after crop harvesting(the autumn fallow period). The characteristics of ammonium nitrogen volatilization, ammonium nitrogen leaching, and nitrate nitrogen leaching in maize soil in black soil area were also determined. The results showed that the application of biogas slurry could increase the organic matter content of soil, and the improvement of soil organic matter by biogas slurry injection was higher than that by spraying. Applying biogas slurry by spraying with the deep turning method under low temperatures during the autumn fallow period could reduce ammonia volatilization from soil. Biogas slurry could be applied by spraying when the amount of nitrogen replacement was <135 kg·hm^-2·d^-1 in the autumn fallow period, and there was no leaching risk of ammonium nitrogen and nitrate nitrogen. However, a potential leaching risk of ammonium nitrogen existed even when the amount of nitrogen replacement was 90 kg·hm^-2·d^-1 using the injection method. The experimental results of both years indicate the feasibility of applying biogas slurry with a reasonable amount of nitrogen replacement and a suitable application mode during the autumn fallow period.