套作玉米经济追施氮素化肥是实现高产低成本的一个重要措施。三年来,我们在京郊部分区县组织了追肥的联合试验。试验目的是为了明确:一、等量化肥在各生育期如何经济有效地分配施用;二、以叶龄为标志,拔节肥在第几片展开叶出现时追施较此合适。 Intercropping corn economy to pursue nitrogen fertilizer is to achieve high yield and low cost an important measure. In the past three years, we organized a joint trial of top dressing in some districts and counties in the suburbs of Beijing. The purpose of the experiment is to clarify: First, the same amount of fertilizer in each growth period of the distribution of economic and effective use; Second, the leaf age as a sign, the first few sections of jointing fertilizer in the leaf when the top dressing is more appropriate.