中文关键词降水量减少农田土壤呼吸作物生物量温度 英文关键词precipitation reductioncroplandsoil respirationcrop biomasstemperature

作者	单位	E-mail
王朝辉	南京信息工程大学江苏省大气环境与装备技术协同创新中心, 南京 210044 南京信息工程大学应用气象学院, 南京 210044	18751312807@163.com
陈书涛	南京信息工程大学江苏省大气环境与装备技术协同创新中心, 南京 210044 南京信息工程大学应用气象学院, 南京 210044	chenstyf@aliyun.com
孙鹭	南京信息工程大学江苏省大气环境与装备技术协同创新中心, 南京 210044 南京信息工程大学应用气象学院, 南京 210044
胡正华	南京信息工程大学应用气象学院, 南京 210044

中文摘要 为研究降水量减少对旱作农田土壤呼吸的影响，设置大豆-冬小麦轮作田间试验.采用随机区组试验，在田间设置对照（CK）、降水量减少20%（P20%）、降水量减少40%（P40%）处理，观测了3个处理土壤呼吸、土壤温度、土壤湿度的季节动态变化，并观测土壤CO₂产生速率、硝化速率、反硝化速率、收获时的作物生物量.结果表明，在大豆生长季，CK、P20%、P40%这3个处理的季节平均土壤呼吸速率分别为（4.91±0.67）、（4.19±0.39）、（4.35±0.32）μmol·（m²·s）^-1，处理间差异未达到显著水平（P>0.05）；在冬小麦生长季，这3个处理的季节平均土壤呼吸速率分别为（2.39±0.17）、（2.03±0.02）、（1.94±0.05）μmol·（m²·s）^-1，表现为CK > P20% > P40%，处理间差异达到显著水平（P>0.05）.降水量减少降低了土壤CO₂产生速率，但对土壤硝化速率和反硝化速率的影响不明显.降水量减少对大豆根、茎叶、籽粒生物量无显著（P>0.05）影响，但显著（P<0.05）降低了冬小麦的根、茎叶、籽粒生物量.土壤温度是影响土壤呼吸季节变异的主要因素，两者间呈指数回归关系，不同处理间的温度敏感系数（Q₁₀）无显著（P>0.05）差异. 英文摘要 To investigate the effects of precipitation reduction on soil respiration in rainfed croplands, a field experiment was performed in a soybean-winter wheat cropland. A randomized block design including three treatments, viz. control (CK), 20% precipitation reduction (P20%), and 40% precipitation reduction (P40%), was used. Seasonal variabilities in soil respiration, soil temperature, and soil moisture were measured. Rates of soil CO₂ production, nitrification and denitrification, and harvested crop biomass were also measured. Results indicated that the seasonal mean soil respiration rates for CK, P20%, and P40% treatments in the soybean growing season were (4.91±0.67), (4.19±0.39), and (4.35±0.32) μmol·(m²·s)^-1, respectively. There was no significant difference (P>0.05) in the mean soil respiration rates between treatments during the soybean growing season. The seasonal mean soil respiration rates for CK, P20%, and P40% treatments during the winter wheat growing season were (2.39±0.17), (2.03±0.02), and (1.94±0.05) μmol·(m²·s)^-1, respectively. There was a significant (P<0.05) difference in the mean soil respiration rates between treatments during the winter wheat growing season. Precipitation reduction decreased the soil CO₂ production rates, but had no obvious impacts on soil nitrification and denitrification rates. Precipitation reduction had no significant (P>0.05) effects on the root, shoot, and seed biomass of soybean, but significantly (P<0.05) decreased the root, shoot, and seed biomass of winter wheat. Soil temperature was the main driver of the seasonal variation in soil respiration. Soil respiration increased exponentially with the increase in soil temperature. There was no significant (P>0.05) difference in the coefficient of temperature sensitivity (Q₁₀) between different treatments. Based on the precipitation reduction experiments of duration longer than one year in previous studies and in our present study, a significant linear regression relationship between the amount of reduced soil respiration and the amount of precipitation reduction was found, indicating that substantial precipitation reduction showed more obvious inhibition effects on soil respiration. This study also suggested that the effects of precipitation reduction on soil respiration varied between crop growing seasons, which may be attributed to the different precipitation intensities in different growing seasons.

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