Soil CO 2 emission from an arable soil was measured by closed chamber method to quantify year round soil flux and to develop an equation to predict flux using soil temperature, dissolved organic carbon(DOC) and soil...Soil CO 2 emission from an arable soil was measured by closed chamber method to quantify year round soil flux and to develop an equation to predict flux using soil temperature, dissolved organic carbon(DOC) and soil moisture content. Soil CO 2 flux, soil temperature, DOC and soil moisture content were determined on selected days during the experiment from August 1999 to July 2000, at the Ecological Station of Red Soil, the Chinese Academy of Sciences, in a subtropical region of China. Soil CO 2 fluxes were generally higher in summer and autumn than in winter and spring, and had a seasonal pattern more similar to soil temperature and DOC than soil moisture. The estimation was 2 23 kgCO 2/(m 2·a) for average annual soil CO 2 flux. Regressed separately, the reasons for soil flux variability were 86 6% from soil temperature, 58 8% from DOC, and 26 3% from soil moisture, respectively. Regressed jointly, a multiple equation was developed by the above three variables that explained approximately 85 2% of the flux variance, however by stepwise regression, soil temperature was the dominant affecting soil flux. Based on the exponential equation developed from soil temperature, the predicted annual flux was 2 49 kgCO 2/(m 2·a), and essentially equal to the measured one. It is suggested the exponential relationship between soil flux and soil temperature could be used for accurately predicting soil CO 2 flux from arable soil in subtropical regions of China.展开更多
Plastic film mulching(PFM)significantly enhances crop yield and quality by increasing soil temperature,reducing water evaporation and optimizing nutrient cycling.However,improper management of plastic film residues ha...Plastic film mulching(PFM)significantly enhances crop yield and quality by increasing soil temperature,reducing water evaporation and optimizing nutrient cycling.However,improper management of plastic film residues has led to microplastic pollution in farmland,posing a major challenge to sustainable agricultural development.The accumulation of microplastics in soil not only affects soil structure but also profoundly impacts crop growth and ecosystem stability by altering nitrogen-related microbial activities and nitrogen(N)cycling processes.This review synthesizes the effects of PFM and microplastics on soil N pools and cycling,exploring their mechanisms in plant N uptake,microbial immobilization,gaseous emissions(e.g.,NH3 and N2O),and N transformation processes(e.g.,N fixation,assimilation,mineralization,nitrification and denitrification).Research indicates that PFM and microplastics significantly influence N processes by modifying soil physicochemical properties and microbial community structure,although their effects vary depending on plastic type,environmental conditions and crop growth stages.Future studies should further investigate the long-term ecological impacts of microplastics in complex natural environments and employ advanced statistical methods and models to quantify their dynamic effects on N cycling.展开更多
文摘Soil CO 2 emission from an arable soil was measured by closed chamber method to quantify year round soil flux and to develop an equation to predict flux using soil temperature, dissolved organic carbon(DOC) and soil moisture content. Soil CO 2 flux, soil temperature, DOC and soil moisture content were determined on selected days during the experiment from August 1999 to July 2000, at the Ecological Station of Red Soil, the Chinese Academy of Sciences, in a subtropical region of China. Soil CO 2 fluxes were generally higher in summer and autumn than in winter and spring, and had a seasonal pattern more similar to soil temperature and DOC than soil moisture. The estimation was 2 23 kgCO 2/(m 2·a) for average annual soil CO 2 flux. Regressed separately, the reasons for soil flux variability were 86 6% from soil temperature, 58 8% from DOC, and 26 3% from soil moisture, respectively. Regressed jointly, a multiple equation was developed by the above three variables that explained approximately 85 2% of the flux variance, however by stepwise regression, soil temperature was the dominant affecting soil flux. Based on the exponential equation developed from soil temperature, the predicted annual flux was 2 49 kgCO 2/(m 2·a), and essentially equal to the measured one. It is suggested the exponential relationship between soil flux and soil temperature could be used for accurately predicting soil CO 2 flux from arable soil in subtropical regions of China.
基金supported by the National Natural Science Foundation of China(42277097)Ordos Science and Technology Major Project,China(ZD20232320)+1 种基金the High-level Talent Program of Hebei Province,China(2024HBQZYCXY037)Professor Station of China Agricultural University at Xinzhou Center for Disease Control and Prevention,and the National Key R&D Program of China(2023YFD1900604).
文摘Plastic film mulching(PFM)significantly enhances crop yield and quality by increasing soil temperature,reducing water evaporation and optimizing nutrient cycling.However,improper management of plastic film residues has led to microplastic pollution in farmland,posing a major challenge to sustainable agricultural development.The accumulation of microplastics in soil not only affects soil structure but also profoundly impacts crop growth and ecosystem stability by altering nitrogen-related microbial activities and nitrogen(N)cycling processes.This review synthesizes the effects of PFM and microplastics on soil N pools and cycling,exploring their mechanisms in plant N uptake,microbial immobilization,gaseous emissions(e.g.,NH3 and N2O),and N transformation processes(e.g.,N fixation,assimilation,mineralization,nitrification and denitrification).Research indicates that PFM and microplastics significantly influence N processes by modifying soil physicochemical properties and microbial community structure,although their effects vary depending on plastic type,environmental conditions and crop growth stages.Future studies should further investigate the long-term ecological impacts of microplastics in complex natural environments and employ advanced statistical methods and models to quantify their dynamic effects on N cycling.
