Phosphorous distribution of plant-soil system in a stipa bungeana slope land in the agro-pastoral transitional zone Soil Content of Phosphorus and Potassium in the Agro-Pastoral Transitional Zone After Cropland Being transformed into Grassland Analysis of the external economic effects of animal husbandry in the agro-pastoral transition zone of North China Response mechanisms of a county territory agro-pastoral system to climate fluctuations in an agro-pastoral transitional zone Effects of establishing perennial artificial grasslands on the availability of soilphosphorus in agro-pastoral transitional zones, Northern China Amylase and Urease Contents in the Soil of Cropland-Turned Grassland in the Agro-pastoral Zone Effects of Returning Cultivated land to Grassland on Soil Chemical Properties in the Agro-pastoral Transitional Zone of Northern China Ecosystem-service-based regionalization of the grassland and agro-pastoral transitional zone in Northern China Effects of Land Use/Cover Changes on Soil Macro-faunal Community in Agro-pastoral Transitional Zone, Northern China