硝化抑制剂阻控养殖肥液灌溉土壤氮素淋失

为考察硝化抑制剂伴施养殖肥液灌溉条件下土壤氮素的淋溶特征和阻控效果,采用土柱模拟淋溶试验,设置尿素溶液单施、养殖肥液单施、以及养殖肥液分别伴施双氰胺(DCD,5%、10%和15%)和氯甲基吡啶(Nitrapyrin,0.25%、0.5%和1%)处理,连续监测了5个灌溉周期土壤淋溶液中铵态氮(NH_4~+-N)、硝态氮(NO_3~--N)、总氮(TN)和溶解性有机碳(DOC)淋失特征。养殖肥液单施比尿素溶液单施显著减少碳氮的淋失浓度和淋失量。养殖肥液伴施DCD和Nitrapyrin淋溶液中TN、NH_4~+-N、NO_3~--N、DOC浓度分别比单施养殖肥液降低27.19%、35.69%、45.89%、53.69%和24.86%、30.87%、21.10%、64%,处理间均达到5%显著水平。从抑制效果及经济节约角度,推荐5%DCD伴施养殖肥液是优化的养分淋溶阻控模式。此外,发现养殖肥液连续饱和灌溉条件下土壤淋溶液硝态氮浓度与氧化还原电位间存在显著的相关性(R2=0.602 8*,n=34)。养殖肥液伴施硝化抑制剂是抑制养分淋失、提高养分利用效率和控制硝态氮淋溶污染的有效措施,但抑制剂的作用效果、抑制时间与施用方式之间的关系还需要进一步研究。

Nitrification inhibitors prevent nitrogen leaching in soil irrigated by biogas slurry

The aim of this study is to investigate the control efficiency of soil nitrogen leaching by nitrification inhibitors under biogas slurry irrigation conditions. Laboratory simulation tests were performed, including urea solution treatment, biogas slurry treatment, and nitrification inhibitors treatments. The concentrations of nitrification inhibitors were 5%, 10%, and 15% of DCD and 0.25%, 0.5%, and 1% of nitrapyrin. Ammonium nitrogen (NH₄⁺-N), nitrate nitrogen (NO₃^--N), total nitrogen (TN), and dissolved organic carbon content (DOC) in the soil leaching solution were monitored for five continuous irrigation cycles. Compared with urea solution group, the application of biogas slurry could reduce the leaching loss of nitrogen and DOC. The concentrations of TN, NH₄⁺-N, NO₃^--N, and DOC in leachate in DCD group were reduced by 27.19%, 35.69%, 45.89%, 53.69%, and in nitrapyrin group by 24.86%, 30.87%, 21.10%, 64%, respectively, with 5% level of significance for various treatments. Considering the cost and control effects, application of DCD at 5% with biogas slurry was recommended as an optimized control mode for preventing nutrient leaching. In addition, a significant correlation was found between nitrate concentration in soil leaching solution and redox potential under continuous saturated biogas irrigation (R²=0.602 8^*, n=34). The application of nitrification inhibitor in biogas slurry is an effective measure to restrict nutrient leaching, improve nutrient utilization efficiency, and control nitrate nitrogen leaching pollution. However, the relationship among the control efficiency, inhibition time, and application methods requires further investigation.