Deeply buried straw retention can improve the soil content of organic matter,its capacity for moisture preservation,the agroecological environment utilization efficiency of water resources,ensuring a stable crop yield...Deeply buried straw retention can improve the soil content of organic matter,its capacity for moisture preservation,the agroecological environment utilization efficiency of water resources,ensuring a stable crop yield;at the same time,the quantitative effects of deeply buried straw retention on soil moisture have a direct influence on the promotion and application of the technology.Using an infiltration and evaporation experiment of a one-dimensional soil column,the effects of straw size on the water content of the straw and the adjacent soil were evaluated when the straw was deeply buried in soil;the infiltration and evaporation features of different sized straw and its adjacent soil were analyzed;the hydraulic conductivity,sorptivity and saturated water content of the straw were obtained;in the end,the water distribution laws of straw and adjacent soil under the same conditions were concluded.The experiment was comprised of rod-shaped straw(RS),segment-shaped straw(SS)and filament-shaped straw(FS)to control treatment(CK).The results indicated that from the perspective of infiltration,the infiltration rate of filament-shape straw was the lowest at the stage of straw unsaturation.The hydraulic conductivities of rod-shaped,filament-shaped and segment-shaped straws are 4.01 mm/min,1.33 mm/min and 0.03 mm/min at the stage of straw and adjacent soil saturation,respectively.There is a strong effect on preventing infiltration from segment-shaped straw;with the help of the Philip model of long duration,the sorptivity of the soil with rod-shaped,filament-shaped and segment-shaped straws was 12.31 mm/min0.5,11.02 mm/min0.5 and 24.26 mm/min0.5 at the unsaturation stage,respectively.The segment-shape straw improved the water absorption capacity of the soil and straw column.The water retention capacities indicated that the saturated water contents of sandy loam,filament-shaped straw,segment-shaped straw and rod-shaped straw were 0.38 cm^(3)/cm^(3),0.29 cm^(3)/cm^(3),0.26 cm^(3)/cm^(3)and 0.13 cm^(3)/cm^(3),respectively.Additionally,the evaporation rate indicated that the soil moisture content of soil below different straw layers retained approximately 30%;that the more crushed the straw was,the more moisture the straw layer lost;and that the cumulative evaporation of rod-shaped straw,filament-shaped straw and segment-shaped straw within 120 days was 1.5 mm,13.5 mm and 25.5 mm,respectively.展开更多
Converting from conventional tillage to no-tillage influences the soil aggregate-size distribution and thus soil organic carbon （SOC） stabilization. However, the dynamics of soil aggregation and the straw-derived ca...Converting from conventional tillage to no-tillage influences the soil aggregate-size distribution and thus soil organic carbon （SOC） stabilization. However, the dynamics of soil aggregation and the straw-derived carbon （C） incorporation within aggregate fractions are not well understood. An experiment was established in 2004 to test the effects of two treatments, no-tillage with residue （NT） and conventional tillage without residue （CT）, on the soil aggregate-size distribution and SOC stabilization in a continuous maize （Zea mays L.） cropping system located in the semiarid region of northern China. Soil samples were collected from the 0-10 cm layer in 2008, 2010 and 2015, and were separated into four aggregate-size classes （〉2, 0.25-2, 0.053-0.25, and 〈0.053 mm） by wet-sieving. In each year, NT soil had a higher proportion of macroaggregates （i.e., 〉2 and 0.25-2 mm） and associated SOC concentration compared with CT. Additionally, to compare straw-derived C incorporation within NT and CT aggregate fractions, ^13C-labeled straw was incubated with intact NT and CT soils. After 90 days, the highest proportion of 13C-labeled straw-derived C was observed in the 〉2 mm fraction, and this proportion was lower in NT than that in CT soil. Overall, we conclude that long-term continuous NT increased the proportion of macroaggregates and the C concentration within macroaggregates, and the physical protection provided by NT is beneficial for soil C sequestration in the continuous maize cropping system in semiarid regions of northern China.展开更多
以玉米秸秆为原材料,在350℃下采用限氧裂解法制备了4种粒径的生物碳(BC-9.31、BC-20.26、BC-71.07、BC-101.90,数字代表样品的中值径,单位μm),对比研究了15℃、25℃、35℃、45℃下生物碳对锶的吸附行为,旨在阐明生物碳粒径和溶液温度...以玉米秸秆为原材料,在350℃下采用限氧裂解法制备了4种粒径的生物碳(BC-9.31、BC-20.26、BC-71.07、BC-101.90,数字代表样品的中值径,单位μm),对比研究了15℃、25℃、35℃、45℃下生物碳对锶的吸附行为,旨在阐明生物碳粒径和溶液温度对生物碳吸附锶的耦合影响。结果表明:生物碳粒径和溶液温度对等温吸附曲线的基本特征影响较小,Freundlich模型能较好地拟合吸附过程(R2=0.915~0.997,N=0.513~0.745);生物碳吸附锶是以熵驱动为主的物理吸附过程,熵变ΔS为75.66~99.43 J/(mol·K),焓变ΔH为18.18~25.84 k J/mol;生物碳对锶的吸附性能大体与溶液温度呈正相关,与颗粒粒径呈负相关,同时颗粒粒径与溶液温度存在耦合影响;生物碳粒径越小,锶吸附过程受温度影响越小;温度越高,锶吸附受粒径影响越小。展开更多
基金the financial support granted from the natural science foundation of Liaoning Province,China(Project No.2015020770)the Ministry of Agriculture,China(Project No.201303125).
文摘Deeply buried straw retention can improve the soil content of organic matter,its capacity for moisture preservation,the agroecological environment utilization efficiency of water resources,ensuring a stable crop yield;at the same time,the quantitative effects of deeply buried straw retention on soil moisture have a direct influence on the promotion and application of the technology.Using an infiltration and evaporation experiment of a one-dimensional soil column,the effects of straw size on the water content of the straw and the adjacent soil were evaluated when the straw was deeply buried in soil;the infiltration and evaporation features of different sized straw and its adjacent soil were analyzed;the hydraulic conductivity,sorptivity and saturated water content of the straw were obtained;in the end,the water distribution laws of straw and adjacent soil under the same conditions were concluded.The experiment was comprised of rod-shaped straw(RS),segment-shaped straw(SS)and filament-shaped straw(FS)to control treatment(CK).The results indicated that from the perspective of infiltration,the infiltration rate of filament-shape straw was the lowest at the stage of straw unsaturation.The hydraulic conductivities of rod-shaped,filament-shaped and segment-shaped straws are 4.01 mm/min,1.33 mm/min and 0.03 mm/min at the stage of straw and adjacent soil saturation,respectively.There is a strong effect on preventing infiltration from segment-shaped straw;with the help of the Philip model of long duration,the sorptivity of the soil with rod-shaped,filament-shaped and segment-shaped straws was 12.31 mm/min0.5,11.02 mm/min0.5 and 24.26 mm/min0.5 at the unsaturation stage,respectively.The segment-shape straw improved the water absorption capacity of the soil and straw column.The water retention capacities indicated that the saturated water contents of sandy loam,filament-shaped straw,segment-shaped straw and rod-shaped straw were 0.38 cm^(3)/cm^(3),0.29 cm^(3)/cm^(3),0.26 cm^(3)/cm^(3)and 0.13 cm^(3)/cm^(3),respectively.Additionally,the evaporation rate indicated that the soil moisture content of soil below different straw layers retained approximately 30%;that the more crushed the straw was,the more moisture the straw layer lost;and that the cumulative evaporation of rod-shaped straw,filament-shaped straw and segment-shaped straw within 120 days was 1.5 mm,13.5 mm and 25.5 mm,respectively.
基金partially supported by the National Natural Science Foundation of China (31171512)the Central Publicinterest Scientific Institution Basal Research Fund, China (Y2017PT26)
文摘Converting from conventional tillage to no-tillage influences the soil aggregate-size distribution and thus soil organic carbon （SOC） stabilization. However, the dynamics of soil aggregation and the straw-derived carbon （C） incorporation within aggregate fractions are not well understood. An experiment was established in 2004 to test the effects of two treatments, no-tillage with residue （NT） and conventional tillage without residue （CT）, on the soil aggregate-size distribution and SOC stabilization in a continuous maize （Zea mays L.） cropping system located in the semiarid region of northern China. Soil samples were collected from the 0-10 cm layer in 2008, 2010 and 2015, and were separated into four aggregate-size classes （〉2, 0.25-2, 0.053-0.25, and 〈0.053 mm） by wet-sieving. In each year, NT soil had a higher proportion of macroaggregates （i.e., 〉2 and 0.25-2 mm） and associated SOC concentration compared with CT. Additionally, to compare straw-derived C incorporation within NT and CT aggregate fractions, ^13C-labeled straw was incubated with intact NT and CT soils. After 90 days, the highest proportion of 13C-labeled straw-derived C was observed in the 〉2 mm fraction, and this proportion was lower in NT than that in CT soil. Overall, we conclude that long-term continuous NT increased the proportion of macroaggregates and the C concentration within macroaggregates, and the physical protection provided by NT is beneficial for soil C sequestration in the continuous maize cropping system in semiarid regions of northern China.
文摘以玉米秸秆为原材料,在350℃下采用限氧裂解法制备了4种粒径的生物碳(BC-9.31、BC-20.26、BC-71.07、BC-101.90,数字代表样品的中值径,单位μm),对比研究了15℃、25℃、35℃、45℃下生物碳对锶的吸附行为,旨在阐明生物碳粒径和溶液温度对生物碳吸附锶的耦合影响。结果表明:生物碳粒径和溶液温度对等温吸附曲线的基本特征影响较小,Freundlich模型能较好地拟合吸附过程(R2=0.915~0.997,N=0.513~0.745);生物碳吸附锶是以熵驱动为主的物理吸附过程,熵变ΔS为75.66~99.43 J/(mol·K),焓变ΔH为18.18~25.84 k J/mol;生物碳对锶的吸附性能大体与溶液温度呈正相关,与颗粒粒径呈负相关,同时颗粒粒径与溶液温度存在耦合影响;生物碳粒径越小,锶吸附过程受温度影响越小;温度越高,锶吸附受粒径影响越小。
