京郊地区小麦、玉米两茬间氮、磷、钾肥的合理施用

在京郊不同土壤肥力条件下,进行小麦、玉米两茬间氮、磷、钾肥合理施用的研究.三年多点试验结果表明,全年氮素投入0.036～0.048kg/m~2,以小麦、玉米各半或玉米居多为宜.冬小麦施氮在下茬玉米上无明显后效.冬小麦适宜施氮量为0.024kg/m~2,夏玉米适宜施氮量0.030kg/m~2,冬小麦和夏玉米施磷肥不仅对当季有增产作用,而且对下茬作物也有明显的后效.冬小麦施P_2O_5 0.015kg/m~2、夏玉米0.007kg/m~2为宜.夏玉米比冬小麦对钾肥高度敏感,土壤速效钾含量在90×10~6以下,冬小麦施钾有一定增产效果,而夏玉米施钾肥显著增产.

N. P. K. Application for Winter Wheat-Summer Maize Double Cropping System in Beijing Suburbs

Experiments were carried out on different type of soils for 3 years. Results were as fellows:1. Half or more than half N should be applied for summer maize, followed by winter wheat, when 0.036-0.048kg / m2was applied every year. Applied N for previous crops had no significant residual effects on the following crops. The appropriate amoui.t of N fertillizer for winter wheat was 0.024 kg/m2, or less than 0.030 kg/m , and for summer maize was more than 0.030 kg / m2.To get higher yield and profit, more amount of N fertilizer should be applied to summer maize.2. P application both for winter wheat and for summer maize had double effects on yield: P -application had significant effects on winter wheat and summer maize, and the residual effects of P application to the previous crops on the yield and P-requirement of the subsequent crops were also significant.Applied P increased maize yield significantly. It was mainly determined by the available P content in soil, the rate of P applied to the previous winter wheat and the rate of applied N for maize.3. Summer maize was more sensitive to K than winter wheat. Applied K increased yield significantly on all experimental sites for maize, but only on sites when soil available K was bellow 90 ppm for winter wheat. Potassium application also had significant residual effects on the subsequent crops. It was suggested that more K fertilizer should be applied to summer maize.4. In view of the above, the principle of fertilizer application for wheat-maize double cropping system in Beijing suburbs should be: (1) For winter wheat, a stable amount of N should be applied and the rate of P application should be increased while K should be supplemented. (2) For summer maize, N rates should be increased while P and K should be applied.