摘　要：为探究气候变化背景下，小麦-大豆轮作体系中小麦季施用硝化抑制剂对大豆土壤无机氮、N2O排放及相关酶活性的后效作用，在控制气室内设置了不同的大气CO₂浓度（400和600 μmol/mol）和气温（环境温度T和T+2℃），在此基础上测定了小麦季添加硝化抑制剂时大豆土壤的硝态氮和铵态氮的含量、土壤硝化-反硝化相关酶活性以及N2O排放量。结果表明，小麦季添加硝化抑制剂配合麦秸还田，使大豆土壤的硝态氮和铵态氮均有所增加，但是对土壤硝化-反硝化酶的活性影响较小。升温（ET）使大豆土壤硝态氮含量显著增加，而铵态氮含量显著降低；大气CO2浓度增加（EC）或同时升高气温和CO2浓度（ECT），土壤硝态氮和铵态氮的含量均有所增加，但与环境高温和CO₂浓度（CK）下的无机氮含量差异不显著。不同环境条件下的土壤硝化-反硝化酶的活性没有明显规律。在ET和ECT条件下，大豆生长季N2O排放总量均显著高于CK处理，且添加硝化抑制剂使N2O排放量降低。EC与CK条件下的N2O排放量差异较小，但在CK条件下，硝化抑制剂处理的N2O排放量显著高于普通尿素处理。综上所述，在气温和CO2浓度升高背景下，硝化抑制剂的合理施用有利于大豆土壤有效氮的增加，但是温度升高（ET和ECT）使N₂O排放量增加，在此条件下添加硝化抑制剂可以减少N2O的排放，单独升高CO2浓度（EC）时，N₂O排放的变化不明显。本研究可为未来气候变化背景下的小麦-大豆轮作施肥管理及农田N2O减排提供理论支持。
关键词：大豆；气候变化；土壤硝态氮；N2O；酶
中图分类号：S565.1                            文献标志码：A                     DOI：10.3969/j.issn.1007-7146.2022.06.011

Abstract: To investigate the effects of nitrification inhibitors applied in the wheat season on the soil inorganic nitrogen (N), N2O emissions and related enzyme activities in the soybean season for the wheat-soybean rotation system under the background of climate change, different atmospheric CO2 concentration (400 and 600 μmol/mol) and air temperature (ambient temperature T and T+2℃) were set in the control air chamber. The contents of soybean soil nitrate and ammonium N, nitrification and denitrification-related enzyme activities and N2O emissions were measured when nitrification inhibitors were added in the wheat season. The results showed that the addition of nitrification inhibitor combined with wheat straw returning to the field in wheat season increased soil nitrate N and ammonium N in soybean season, whereas it had little effect on the enzyme activities of soil nitrification-denitrification. Elevated air temperature (ET) significantly increased the content of nitrate N in soybean soil, while the content of ammonium N significantly decreased. At the conditions of increased atmospheric CO2 concentration (EC) or simultaneously increased air temperature and CO2 concentration (ECT), soil nitrate N and ammonium N content both increased, whereas there were no significantly difference with the inorganic N content under ambient temperature and CO2 concentration (CK). The enzyme activities of soil nitrification-denitrification under different environmental conditions showed no obvious regularity. Under ET and ECT conditions, the total amount of N2O emission in soybean growing season was significantly higher than that in CK treatment, and the addition of nitrification inhibitors reduced N2O emission. The difference of N2O emissions between EC and CK conditions was small, whereas the N2O emission of nitrification inhibitor treatment was significantly higher than that of common urea treatment under CK condition. To sum up, under the background of rising air temperature and CO2 concentration in the future, reasonable application of nitrification inhibitors is beneficial to the increase of available N in soybean soil, whereas the increase of air temperature (ET and ECT) may increase N2O emissions, and adding nitrification inhibitors can reduce N2O emissions. The changes in N2O emissions are not obvious when the CO2 concentration (EC) increased alone. This study can provide a theoretical support for fertilization management and farmland N2O emission reduction under the wheat-soybean crop rotation system under the background of future climate change.
Key words: soybean; climate change; soil nitrate nitrogen; N2O; enzyme
（Acta Laser Biology Sinica, 2022, 31(6): 559-567）