Abstract:

This study investigated the dynamics of soil phosphorus,yield responses to soil phosphorus and phosphate fertilizer in winter wheat-summer maize rotation system in the last decades,which was important for the scientific application of phosphate fertilizer in continuous high-yielding cropping.A combined method that included in situ phosphate fertilizer experiment under different soil fertility conditions,the analysis of changes of soil available P since 1978,the response of yield to phosphate fertilizer was used.Average content of soil available P of winter wheat-summer maize rotation area was 22.43 mg/kg,and the soil available P of the piedmont plain of Taihang mountain was greater than the alluvial plain.During 1996-1999,the soil available P content of the the piedmont plain and the alluvial plain was 15.09,11.90 mg/kg in cultivated land,respectively,the application rate of P₂O₅ in the winter wheat season of the rotation system was 180 kg/ha;the soil P supply capacity for winter wheat in these two regions piedmont were 83.9%,75.8%,respectively,and for summer maize they were 83.3%,89.7%,respectively.Under the condition of winter wheat straw returning,soil P surplus of these two regions was estimated to be 52.8%,55.4%,respectively.During 2010-2012,the soil available P of the piedmont plain of Taihang mountain was 27.22 mg/kg,the application rate in winter wheat and summer maize season were 108,60 kg/ha,respectively.The soil P supply capacity in winter wheat season was 84.6%,90.1% in summer maize season.Soil P surplus was estimated to be 6.7% in winter wheat season,and soil P of deficit was estimated to be 47.1% in summer maize season without straw returning.The application rate of P₂O₅ for the maximal yield production of winter wheat and summer maize were calculated according to the yield responses of winter wheat and summer maize to the P fertilization rates at multiple sites during 2002-2006 and 2012-2016.For winter wheat they were 107.3,125.1 kg/ha,respectively,and for summer maize they were 52.0,58.9 kg/ha,respectively.The accumulated P increaded the yield of winter wheat and summer maize for excess application 3 time of P fertilizer in 3 years 6 crop.The recommendation of P₂O₅ rate for winter wheat and summer maize with wheat straw returning were 90-100 kg/ha and 30 kg/ha,respectively,and they were 100-120 kg/ha and 45 kg/ha without wheat straw returning.

Key words: Winter wheat-summer maize rotation, Soil phosphorus, Phosphate fertilizer, Phosphorus supply capacity, Yield response