Effects of organic fertilization on soil nutrient, enzyme activity and crop productivity in semi-arid areas of southern Ningxia

To provide a theoretical basis for establishing the organic fertilization system in the semi-arid areas of southern Ningxia, the effects of organic fertilization, taking no organic fertilizer as the control, on soil nutrient, enzyme activity and crop productivity were studied under different organic fertilizer treatments (H: 90 000 kg/ha, M: 60 000 kg/ha, L: 30 000 kg/ha) for four years (20072010). After the winter wheat harvest (2010), the results of four years field experiment show that different organic fertilizer amounts have different effects on the contents of soil nutrient, Urease, Phosphatase, Catalase and Invertase activities of 060 cm soil layer, the order is: high and middle straw returning treatments＞low straw returning treatments＞CK, the fertilizer treatments have significant differences with the CK. Compared with the CK, with the reduction of organic fertilizer applications, the yield are increased by 35.05%, 20.77% and 11.51% (P0.01), the crop water use efficiencies are increased by 38.26%, 22.61% and 11.88% (P0.01). The study shows that in semi-arid areas of southern Ningxia, the organic fertilizer technology can play an active role in improving soil nutrient, promoting enzyme activity, increasing crop yield and crop water use efficiency significantly.