摘要:揭示尿素类肥料添加生化抑制剂组合后，在黄泥田土壤中硝态氮（NO₃^--N）和铵态氮（NH₄⁺-N）的淋溶损失规律。采用室内土柱淋溶培养试验，研究脲酶抑制剂N-丁基硫代磷酰三胺（NBPT）和硝化抑制剂2-氯-6-（三氯甲基）吡啶（CP）单独添加及配合施用对尿素和尿素硝铵（300 kg N/hm²）中氮（N）素在土体中淋溶损失的影响。结果表明：尿素和尿素硝铵处理淋溶液中NH₄⁺-N和NO₃^--N浓度均呈先升后降的变化趋势，而出峰时间不一。NH₄⁺-N和NO₃^--N淋失量随着时间的延长，处理间差异逐渐变大。NBPT处理可以减缓尿素水解，有效抑制NH₄⁺-N生成，延缓其出峰时间，减少NH₄⁺-N流失；CP处理可以有效抑制NH₄⁺-N向NO₃^--N转化，减少NO₃^--N流失。与单独添加NBPT和CP处理相比，两者配施对N素淋溶损失有明显的协同抑制效果在黄泥田土壤中，既能减缓尿素水解，保持土壤中较高NH₄⁺-N含量，又能降低淋溶液中NO₃^--N浓度。培养结束时（第72天），UAN处理中NO₃^--N、NH₄⁺-N、矿质态N淋失总量及硝化率较U处理高34.39%、5.32%、31.72%和15.71%。U+NBPT、U+CP和U+NBPT+CP处理较U处理分别显著降低NO₃^--N淋失总量达15.58%、114.77%和73.45%；UAN+NBPT、UAN+CP和UAN+NBPT+CP处理较UAN处理分别显著降低达15.88%、54.87%和37.46%。不同处理NO₃^--N淋失总量大小表现为：UAN > UAN+NBPT > U > UAN+NBPT+CP > U+NBPT > UAN+CP > U+NBPT+CP > U+CP > CK。在一定施肥量条件下，NBPT和CP单独施用或配施均可降低黄泥田土壤中NO₃^--N累积淋失量。对各处理淋溶液中NO₃^--N淋失量（y）随时间（x）的变化进行拟合，其中以线性方程（y=ax+b）的拟合度较高，且各抑制剂处理a、b值均存在明显差异。总体认为，在黄泥田土壤中施用CP及其与NBPT配施可以显著降低土壤NO₃^--N淋溶损失，减少N素淋失风险，提高肥料利用率。



Abstract:The objective of this study was to determine the effects of combined biochemical inhibitors on the transformation and leaching loss of NO₃^--N and NH₄⁺-N from urea-based fertilizer in yellow clayey soil. A soil column leaching experiment was conducted in a greenhouse to observe nitrogen (N) transformation and leaching loss following the application of urea and UAN (300 kg N/hm²) with a urease inhibitor N-(n-butyl) thiophosphoric triamide (NBPT), a nitrification inhibitor 2-chloro-6-(trichloromethyl) pyridine (CP), or both. The results showed that the contents of NH₄⁺-N and NO₃^--N from the leacheate of urea and UAN both rose first and then fell with different peak times. The differences in the leaching loss of NH₄⁺-N and NO₃^--N across treatments increased over time. NBPT can slow urea hydrolysis, and effectively inhibit the generation of NH₄⁺-N to retard the peak time and reduce NH₄⁺-N loss. CP can effectively inhibit the transformation of NH₄⁺-N to NO₃^--N to reduce NO₃^--N loss. Compared with the application of NBPT and CP alone, their combination exhibited a synergistic inhibition effect on N leaching loss in yellow clayey soil, namely not only did it slow down urea hydrolysis and maintain high NH₄⁺-N content in the soil, but it also reduced NO₃^--N content in the leacheate. At the end of the incubaton (72 days), the leaching loss of NO₃^--N, NH₄⁺-N, and mineral N, and nitrification rate from UAN treatment were higher than those from the U treatment by 34.39%, 5.32%, 31.72%, and 15.71%, repectively. Compared with the U treatment, U+NBPT, U+CP, and U+NBPT+CP treatments significantly reduced the leaching loss of NO₃^--N by 15.58%, 114.77%, and 73.45%, respectively. Compared with UAN treatment, UAN+NBPT, UAN+CP, and UAN+NBPT+CP treatments significantly reduced leaching loss by 15.88%, 54.87%, and 37.46%, respectively. The leaching loss of NO₃^--N from different treatments ranked UAN > UAN+NBPT > U > UAN+NBPT+CP > U+NBPT > UAN+CP > U+NBPT+CP > U+CP > CK. Within a certain range of fertilizer rate, adding NBPT and CP alone or both can reduce NO₃^--N leaching loss in yellow clayey soil. Equation models were used to describe the relationship between NO₃^--N leaching loss (y) and time (x). The linear equation (y=ax+b) fit well, a and b values in adding inhibitor treatments were obviously different. In conclusion, application of NBPT in yellow clayey soil combined with CP can significantly reduce the leaching loss of soil NO₃^--N and N leaching risk, to improve fertilizer use efficiency.





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