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CO_2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·(m^2·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·(m^2·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CO_2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.
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·（m^2·s）^-1,espectively. 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·（m^2·s）^-1,espectively. 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.
作者
王朝辉
陈书涛
孙鹭
胡正华
WANG Zhao-hui;CHEN Shu-tao;SUN Lu;HU Zheng-hua;Jiangsu Collaborative Innovation Center of Atmospheric Environment and Equipment Technology(CICAEET） ,Nanjing University of Information Science and Technology;School of Applied Meteorology,Nanjing University of Information Science and Technolog)
出处
《环境科学》
EI
CAS
CSCD
北大核心
2018年第4期1943-1951,共9页
Environmental Science
基金
国家自然科学基金项目(41775151
41775152)
江苏省"六大人才高峰"项目(2015-NY-012)
关键词
降水量减少
农田
土壤呼吸
作物生物量
温度
precipitation reduction
cropland
soil respiration
crop biomass
temperature
