Precipitation is the major driver of ecosystem functions and processes in semiarid and arid regions. In such waterlimited ecosystems, pulsed water inputs directly control the belowground processes through a series of ...Precipitation is the major driver of ecosystem functions and processes in semiarid and arid regions. In such waterlimited ecosystems, pulsed water inputs directly control the belowground processes through a series of soil drying and rewetting cycles. To investigate the effects of sporadic addition of water on soil CO2 effux, an artificial precipitation event （3 mm） was applied to a desert shrub ecosystem in the Mu Us Sand Land of the Ordos Plateau in China. Soil respiration rate increased 2.8 4.1 times immediately after adding water in the field, and then it returned to background level within 48 h. During the experiment, soil CO2 production was between 2 047.0 and 7 383.0 mg m^-2. In the shrubland, soil respiration responses showed spatial variations, having stronger pulse effects beneath the shrubs than in the interplant spaces. The spatial variation of the soil respiration responses was closely related with the heterogeneity of soil substrate availability. Apart from precipitation, soil organic carbon and total nitrogen pool were also identified as determinants of soil CO2 loss in desert ecosystems.展开更多
To better understand the key role of biological soil crusts(BSCs) in redistribution processes of limited water resources in semi-arid sandy ecosystems,surface runoff over BSCs in a sandy area in the southern Mu Us san...To better understand the key role of biological soil crusts(BSCs) in redistribution processes of limited water resources in semi-arid sandy ecosystems,surface runoff over BSCs in a sandy area in the southern Mu Us sandy area was observed in this study.The results indicated that runoff occurred twice among six rainfall events during the experimental period.Runoff yields varied among types of BSCs,and that they increased in the following order:light algae crusts,dark algae crusts and moss crusts.These findings showed that runoff yields were increasing with the development of BSCs.The percentage of runoff in individual rainfall events increased from light algae crusts to moss crusts,which indicated that the redistribution ratios of different types of BSCs differed.Surface runoff of BSCs may be influenced by rainfall,rain intensity,degree of water saturation of the BSCs before the rain and degree of development of BSCs.Formation of BSCs on the surface of sand dunes changed the spatial distribution pattern of water in this semi-arid sandy ecosystem,which increased the heterogeneity of resources such as water and nutrients.Therefore,making appropriate disturbances of BSCs during storm season is beneficial to maintaining the balance of natural resources in the semi-arid sandy ecosystem.展开更多
Depended on the analysis of ground snow situation, soil moisture loss speed and soil structure after planting crops of Mu Us Sandy Land remedied with feldspathic sandstone in the fallow period, it is concluded that fe...Depended on the analysis of ground snow situation, soil moisture loss speed and soil structure after planting crops of Mu Us Sandy Land remedied with feldspathic sandstone in the fallow period, it is concluded that feldspathic sandstone mixed with sand improved the sand stabilization in the governance of Mu Us Sandy Land in the fallow period. The sandy land remedied with feldspathic sandstone had big snow coverage, 25%-75% higher than normal sand; soil moisture losses slowed down, and moisture content rose by over 3 times; soil structure had been improved, and water stable aggregate content increased by 6.52%-18.04%; survival rate of protection forest increased to 85%; and ground flatness is less than 1%. The above conditions weakened sand rising conditions of Mu Us Sandy Land in the fallow period and formed two protective layers of snow cover and soil frozen layer under cold weather so as to prevent against wind erosion.展开更多
基金Project supported by the National Natural Science Foundation of China (Nos. 40730105, 40501072 and 40673067)the National Key Basic Research Program (973 Program) of China (No. 2002CB412503)the Knowledge Innovation Program of the Chinese Academy of Sciences (No. KZCX2-YW-149)
文摘Precipitation is the major driver of ecosystem functions and processes in semiarid and arid regions. In such waterlimited ecosystems, pulsed water inputs directly control the belowground processes through a series of soil drying and rewetting cycles. To investigate the effects of sporadic addition of water on soil CO2 effux, an artificial precipitation event （3 mm） was applied to a desert shrub ecosystem in the Mu Us Sand Land of the Ordos Plateau in China. Soil respiration rate increased 2.8 4.1 times immediately after adding water in the field, and then it returned to background level within 48 h. During the experiment, soil CO2 production was between 2 047.0 and 7 383.0 mg m^-2. In the shrubland, soil respiration responses showed spatial variations, having stronger pulse effects beneath the shrubs than in the interplant spaces. The spatial variation of the soil respiration responses was closely related with the heterogeneity of soil substrate availability. Apart from precipitation, soil organic carbon and total nitrogen pool were also identified as determinants of soil CO2 loss in desert ecosystems.
基金supported by the National Natural Science Foundation of China (401171002)the Fundamental Research Funds for Central Universities
文摘To better understand the key role of biological soil crusts(BSCs) in redistribution processes of limited water resources in semi-arid sandy ecosystems,surface runoff over BSCs in a sandy area in the southern Mu Us sandy area was observed in this study.The results indicated that runoff occurred twice among six rainfall events during the experimental period.Runoff yields varied among types of BSCs,and that they increased in the following order:light algae crusts,dark algae crusts and moss crusts.These findings showed that runoff yields were increasing with the development of BSCs.The percentage of runoff in individual rainfall events increased from light algae crusts to moss crusts,which indicated that the redistribution ratios of different types of BSCs differed.Surface runoff of BSCs may be influenced by rainfall,rain intensity,degree of water saturation of the BSCs before the rain and degree of development of BSCs.Formation of BSCs on the surface of sand dunes changed the spatial distribution pattern of water in this semi-arid sandy ecosystem,which increased the heterogeneity of resources such as water and nutrients.Therefore,making appropriate disturbances of BSCs during storm season is beneficial to maintaining the balance of natural resources in the semi-arid sandy ecosystem.
基金The public welfare scientific research of Ministry of Land and Resources,No.201411008
文摘Depended on the analysis of ground snow situation, soil moisture loss speed and soil structure after planting crops of Mu Us Sandy Land remedied with feldspathic sandstone in the fallow period, it is concluded that feldspathic sandstone mixed with sand improved the sand stabilization in the governance of Mu Us Sandy Land in the fallow period. The sandy land remedied with feldspathic sandstone had big snow coverage, 25%-75% higher than normal sand; soil moisture losses slowed down, and moisture content rose by over 3 times; soil structure had been improved, and water stable aggregate content increased by 6.52%-18.04%; survival rate of protection forest increased to 85%; and ground flatness is less than 1%. The above conditions weakened sand rising conditions of Mu Us Sandy Land in the fallow period and formed two protective layers of snow cover and soil frozen layer under cold weather so as to prevent against wind erosion.
