关键词: 水稻, 水稻, 穗型, 氮肥水平, 产量结构

Abstract: Based on environmental characteristics and the requirement and use efficiency of heat and water resources by grass in their developing process，this paper estimates the potential grassland productivity in quantities by using Miami Model of seven counties in agriculture and pasturage interlaced zone of northern shaanxi. We compare it with grassland actual productivity. It is surveyed that in this region the grassland actual productivity is 30.80% of the potential grassland productivity. At the same time, this paper grasps the status and character of grassland productivity basically, hereby describes the exploitive stratagem and guiding suggestions of improving the grassland productivity.