Revision of fertilizer recommendation for wheat and maize rotation in Taihang piedmont of North China

To improve fertilizer management in North China, long-term fertilizer experiments were conducted to test yield effects of fertilizer N, P and K, for winter wheat and summer maize, two staple crops of the region. For N fertilizer, three regression procedures were adopted to analyze crop yields response to fertilizer N. The results indicated that the linear-plateau model was the best to simulate the relationships of N response to wheat and maize yield. The optimal nitrogen fertilizers of winter wheat and summer maize were 91 kg N/hm² and 39.7 kg N/hm², respectively, less than 59% and 79.7% amount of the traditional fertilization——recommended by the quadratic model for this region. Before wheat and maize planting, the basal fertilizer N was decided by considering both the optimal fertilization rate and the soil nitrate(0～60 cm) content. Based on the long-term experiment for nutrient balance, P₂O₅ 75 kg/hm² and K₂O 45 kg/hm² should be applied before winter wheat sowing in each rotation season, and it is essential for peasants to return wheat straws back to soils. By using the indicators, 407.4 yuan/hm² and 503.8 yuan/hm² used for buying fertilizers would be saved during a wheat season and maize season, respectively.