Abstract:In order to explore the effects of organic materials combined with rainwater collection measures (OMR) on soil physicochemical properties of apple orchard under rain-fed conditions on the Loess Plateau, apple orchards in Yan'an of Shaanxi Province were selected to conduct the experiments in April 2016. Fish scale pit and rain-collecting pit were conducted on the reverse slope of crown projection surface of apple trees, and the effects of different dosages of organic materials (5 250 kg/hm2 (OMR1), 4 500 kg/hm2 (OMR2), 3 750 kg/hm2 (OMR3) and 0 kg/hm2 (CK)) and traditional treatment (T) on soil physicochemical properties were studied. Soil water content and electrical conductivity in 0-300 cm soil layer, nitrate nitrogen content in 0-200 cm soil layer and soil bulk density and saturated hydraulic conductivity in 0-100 cm soil layer were determined. The results showed that OMR could significantly increase the soil moisture content in 0-300 cm soil layer, and the average soil moisture content increased most significantly in OMR2 treatment. The soil root wetting areas in OMR1, OMR2 and OMR3 treatment were mainly concentrated in 0-100 cm soil layer. In the 0-300 cm soil layer, the multiple average moisture content of OMR2 treatment was the highest (14.87%), while that of OMR1, OMR3, CK and T treatment was 14.74%, 14.80%, 12.79% and 8.66%, respectively. The OMR could significantly increase the content of nitrate nitrogen in 0-200 cm soil layer, especially in 40-100 cm soil layer. The OMR could significantly reduce soil bulk density, especially the bulk density of 20-60 cm soil layer. The OMR could increase soil saturated hydraulic conductivity, especially in 0-40 cm soil layer. The OMR could increase soil electrical conductivity, and the peak value appeared in 60-100 cm soil layer, and the electrical conductivity of 0-300 cm soil layer followed the order of OMR2 > OMR1 > OMR3 > CK > T. Overall, the OMR in Yan'an, Shaanxi could significantly improve soil moisture content, and nitrate nitrogen content, soil saturated hydraulic conductivity and electrical conductivity, reduce soil bulk density, with make fruit trees grow in suitable environment and promote sustainable development of local fruit industry.