Spatial Variation of Topsoil Bulk Density of Farmland on County Level in Northwest Arid Area

Spatial variation of soil bulk density for farmland topsoil was measured and analyzed by using traditional statistics and geostatistics,which was performed in typical region of northwest arid area in Pingluo county of Ningxia.The results showed that the top soil bulk density of farmland ranged from 1.079 g/cm3 to 1.612g/cm3,with the mean was(1.355±0.107)g/cm3 and the variation coefficient was 0.080in studied area.The topsoil bulk density had a weak variability and decreased gradually from west to east,but it showed the certain north-south zonal distribution pattern in spatial variation on county scale.Soil texture and land use patterns were the key factors which affected soil bulk density variation on county scale.