Note:
Different letters indicate
significant differences among different land use patterns in the same
soil layer (p < 0.05). AG: alfalfa artificial
grassland. WM: wheat-maize rotation field. PC: native grassland. pH:
hydrogen ion concentration. EC: soil electrical conductivity. SOC: soil
organic carbon. NH4+-N: ammonium
nitrogen. NO3--N: nitrate nitrogen.
AP: soil available phosphorus.