Laboratory and in situ experiments were done to investigate the influences of cultivation on temperate semi arid grassland (for 17 years spring wheat planted once every two years without fertilization) on soil N ...Laboratory and in situ experiments were done to investigate the influences of cultivation on temperate semi arid grassland (for 17 years spring wheat planted once every two years without fertilization) on soil N 2O emission and quantitative variations of related soil microbes. In the laboratory (25℃ and soil moisture 18%), cultivation increased soil transformations of fertilizer nitrogen (100 μg N/g as NaNO 3, urea, or as urea with dicyandiamide 1 μg N/g). The N 2O emissions from the cultivated and uncultivated soils with or without nitrogen additions were relatively low, and mainly originated from the nitrification. The soil N 2O emission due to cultivation decreased somewhat upon no fertilization or NaNO 3 addition, but significantly upon urea addition. The role of dicyandiamide as nitrification inhibitor was only considerable in the cultivated soil, and had small influence on decreasing N 2O emission in the two soils. The influence of cultivation on soil N 2O emission was also reflected by the number variations of microbes related with soil nitrogen transformation in the two soils. Compared to the uncultivated grassland, in situ ammonifiers and denitrifiers in the cultivated grassland quantitatively averagely increased, and aerobic no symbiotic azotobacters were quantitatively similar, leading to the continued decrease of organic matter content and the decrease of N 2O emission from the cultivated grassland soil.展开更多
In arid and semiarid regions,cultivation and shrub invasion are two important factors to impact grassland.However,there are few studies to compare the effects of cultivation and shrub invasion on soil physical,chemica...In arid and semiarid regions,cultivation and shrub invasion are two important factors to impact grassland.However,there are few studies to compare the effects of cultivation and shrub invasion on soil physical,chemical and mineralogical properties.In this study,three sampling sites,which respectively represent the native grassland,cultivated grassland(farmland),and shrub invasion of grassland(shrub land)in Mu Us sand land,were selected and soil samples were collected and measured for soil particle size distribution(PSD),soil organic carbon(SOC),total nitrogen(TN)and total phosphorous(TP)concentrations,and relative percentages of mineralogical components.Results showed that cultivation and shrub invasion significantly altered the soil PSD,soil C,N and P concentrations and pools,and the relative percentages of soil mineralogical components of the grassland ecosystems.Grassland cultivation and shrub invasion significantly decreased the contents of silt and clay.Moreover,the land cover change from grassland to farmland or shrubland significantly resulted in soil organic carbon,total nitrogen and soil carbonate loss.In this study,we found that grassland cultivation resulted in more sand accumulation and more soil C and N losses than shrub invasion,which indicated that grassland cultivation was stronger than shrub invasion to accelerate soil desertification in Mu Us sand land.展开更多
The Tibetan Plateau is vital for animal husbandry in China,and relies heavily on its natural grasslands.However,grassland degradation,increasing livestock numbers,and uneven grazing practices are exacerbating the gras...The Tibetan Plateau is vital for animal husbandry in China,and relies heavily on its natural grasslands.However,grassland degradation,increasing livestock numbers,and uneven grazing practices are exacerbating the grass-livestock imbalance.Cultivated grasslands are a key strategy to address this issue.In this review,we evaluate the current status,challenges,and suggestions for developing and managing Tibetan Plateau cultivated grasslands.While discernible advancements have been made in the cultivated grasslands in this region,persistent challenges exist.These challenges stem from issues like low awareness and enthusiasm among farmers and herders,uneven cultivated grassland distribution,and limited scientific and technological contributions.Based on these challenges,we propose strengthening the promotion of artificial forage,implementing a rationalized grassland layout,and improving the scientific and technological contributions to forage species selection,sowing,management,and storage.In summary,cultivated grasslands in the Tibetan Plateau offer promising prospects but still face significant challenges.Overcoming these obstacles will require innovative approaches to unlock the full potential of cultivated grasslands in this unique ecological niche.展开更多
文摘Laboratory and in situ experiments were done to investigate the influences of cultivation on temperate semi arid grassland (for 17 years spring wheat planted once every two years without fertilization) on soil N 2O emission and quantitative variations of related soil microbes. In the laboratory (25℃ and soil moisture 18%), cultivation increased soil transformations of fertilizer nitrogen (100 μg N/g as NaNO 3, urea, or as urea with dicyandiamide 1 μg N/g). The N 2O emissions from the cultivated and uncultivated soils with or without nitrogen additions were relatively low, and mainly originated from the nitrification. The soil N 2O emission due to cultivation decreased somewhat upon no fertilization or NaNO 3 addition, but significantly upon urea addition. The role of dicyandiamide as nitrification inhibitor was only considerable in the cultivated soil, and had small influence on decreasing N 2O emission in the two soils. The influence of cultivation on soil N 2O emission was also reflected by the number variations of microbes related with soil nitrogen transformation in the two soils. Compared to the uncultivated grassland, in situ ammonifiers and denitrifiers in the cultivated grassland quantitatively averagely increased, and aerobic no symbiotic azotobacters were quantitatively similar, leading to the continued decrease of organic matter content and the decrease of N 2O emission from the cultivated grassland soil.
基金National Basic Research Program of China(2010CB833400)
文摘In arid and semiarid regions,cultivation and shrub invasion are two important factors to impact grassland.However,there are few studies to compare the effects of cultivation and shrub invasion on soil physical,chemical and mineralogical properties.In this study,three sampling sites,which respectively represent the native grassland,cultivated grassland(farmland),and shrub invasion of grassland(shrub land)in Mu Us sand land,were selected and soil samples were collected and measured for soil particle size distribution(PSD),soil organic carbon(SOC),total nitrogen(TN)and total phosphorous(TP)concentrations,and relative percentages of mineralogical components.Results showed that cultivation and shrub invasion significantly altered the soil PSD,soil C,N and P concentrations and pools,and the relative percentages of soil mineralogical components of the grassland ecosystems.Grassland cultivation and shrub invasion significantly decreased the contents of silt and clay.Moreover,the land cover change from grassland to farmland or shrubland significantly resulted in soil organic carbon,total nitrogen and soil carbonate loss.In this study,we found that grassland cultivation resulted in more sand accumulation and more soil C and N losses than shrub invasion,which indicated that grassland cultivation was stronger than shrub invasion to accelerate soil desertification in Mu Us sand land.
基金The Central Government Leading Project for Tibetan Science and Technology Development(XZ202202YD0028C)The Entrusted Project ofthe Development Research Center,National Forestry and Grassland Administration(JYC-2022-0053)The Natural Science Foundation of Tibet(XZ202201ZR0063G).
文摘The Tibetan Plateau is vital for animal husbandry in China,and relies heavily on its natural grasslands.However,grassland degradation,increasing livestock numbers,and uneven grazing practices are exacerbating the grass-livestock imbalance.Cultivated grasslands are a key strategy to address this issue.In this review,we evaluate the current status,challenges,and suggestions for developing and managing Tibetan Plateau cultivated grasslands.While discernible advancements have been made in the cultivated grasslands in this region,persistent challenges exist.These challenges stem from issues like low awareness and enthusiasm among farmers and herders,uneven cultivated grassland distribution,and limited scientific and technological contributions.Based on these challenges,we propose strengthening the promotion of artificial forage,implementing a rationalized grassland layout,and improving the scientific and technological contributions to forage species selection,sowing,management,and storage.In summary,cultivated grasslands in the Tibetan Plateau offer promising prospects but still face significant challenges.Overcoming these obstacles will require innovative approaches to unlock the full potential of cultivated grasslands in this unique ecological niche.
