冬小麦-夏玉米轮作体系中磷钾平衡的研究

对高肥力土壤大量施用磷钾肥冬小麦 /夏玉米轮作周期中作物产量、磷钾养分平衡等进行了研究。结果表明 ,高肥力土壤上连续大量施用磷钾肥条件下 ,传统施氮与优化施氮、秸秆还田与秸秆不还田对冬小麦和夏玉米产量、磷钾吸收量均无显著差异。在一个轮作周期中 ,冬小麦、夏玉米吸磷 (P)量分别为 22～25、18～19kg/hm2;吸钾(K)量分别为 14.7～16.6、96～112kg/hm2。在一个轮作周期后 ,土壤中的速效磷、速效钾含量变化不大。在施用磷肥 (P) 79kg/hm2 的条件下 ,无论秸秆还田与否磷素都有盈余 ,秸秆还田磷素 (P)盈余量为 46～47kg/hm2,秸秆不还田为 36～37kg/hm2;在施用钾肥 (K)75kg/hm2条件下 ,秸秆还田钾素 (K)盈余量为 22～31kg/hm2,秸秆不还田钾素 (K)亏缺量为 168～201kg/hm2,说明秸秆还田对于磷素与钾素特别是钾素的平衡有很大的作用

Study on balance of phosphorus and potassium in winter wheat and summer maize rotation system

The effects of a great deal of P and K fertilizers on crop yield,P,K uptake and balance and the dynamics of available P and K of soil in winter wheat/summer maize rotation system were studied The results indicated that grain yields of winter wheat and summer maize had no significant differences between with or without straw treatments and also no significant differences between conventional N fertilization and optimized N fertilization treatments The uptakes by winter wheat and summer maize were P 22～25,18～19kg/hm² and K 147～166,96～112 kg/hm²,respectively The available P and K in soil almost had no change after a rotation period Available P and available K in soil were above 30 and 148mg/kg in soil The balance of P in with and without straw treatment had surplus 46～47 and 36～37kg/hm² when the P application rate was 79 kg/hm² (P),and K had surplus 22～31 kg/hm² in with straw treatment and had deficit 168 ～201 kg/hm² in without straw treatment when the K application rate was K 75 kg/hm² It was suggested that straw return to the field had great effects on balance of P and K,especially K