Distribution features of soil water content in the profile of rainfed cropland with long-term fertilization

This study was conducted in the long-term experimental field at the Changwu tableland on the Loess Plateau to determine the relationship between soil water content and fertilization method and amount and analyze the hydrological and ecological consequences of water consumption in lower soil layers by comparing the effect of fertilization on soil water distribution in soil profiles.The experimental design consisted of a control treatment(CK) and 10 fertilization treatments with different nitrogen,phosphorus and potassium applications.The soil water in 0300 cm layer was supplied by precipitation in rainy season, but soil water deficit existed at sowing stage of winter wheat.In general,the average soil water content of 100300 cm profile was lower than that of 0100 cm and 300600 cm in all treatments because of more intensive water consumption in this layer.Fertilization with phosphorus alone was not significantly different from the control treatment with relatively higher soil moisture.Nitrogen applied alone or with phosphorus together increased water utilization of the lower soil layer.Soil water content decreased with more phosphorus use under the same amount of nitrogen application and changed little after P rate reached 45 kg/ha.Nitrogen application also increased soil water consumption at the same rate of P application;however,soil water content reached a steady level after nitrogen application reached 90 kg/ha.Potassium application had no significant effect on soil moisture in this experiment.