贺兰山东麓约有300万亩淡灰钙土,从洪积扇到洪积冲积倾斜平原,可划分为不同的立地类型.开发利用本地区大面积的淡灰钙土,要根据不同类型,做到因地制宜.如果发展林业,一定要考虑立地类型,做到适地适树.我们在镇北堡发现同年栽种的杨树长势差别很大,为弄清原因,我们对本地区土壤 Helan Mountain at the foot of about 3000000 acres of light gray earth, from alluvial fan to alluvial alluvial slope plains, can be divided into different types of sites.Development and utilization of a large area of ​​light gray earth, according to different types, So as to local conditions .If the development of forestry, we must consider the type of site, so fit tree .We found in Zhenbei Fort poplar grown in the same year the growth is very different, in order to find out the reason, we are the region soil