Improvement Effectiveness On Saline Soil By Using Several Crops In The Hexi Corridor, China

As a kind of land resource,saline land has been paid increasingly attention because of the shortage of land resource in Gansu province of China.Therefore,it is urgent to explore and utilize saline land,especially in the northwest China where land ecosystem is fragile.The objective of this study is to find a way to improve and utilize saline land for sustainable development.The experiments were carried out at in Hongfeng Company locating in Jiuquan and Jiayuguan and zhangye pass,Gansu province,China.10 land utilized groups,Gobi open land,1-year-old alfalfa land,2-year-old alfalfa land,3-year-old alfalfa land,4-year-old alfalfa land,8-year-old alfalfa land,25-year-old alfalfa land,barley land,wheat land and benne land,were chosen to compare the contents of the total salt,the organic matter,pH,total nitrogen,ammonium,nitrate and solubility ions in the soils for disclosing adaptability and improvement effectiveness.The conclusions were presented as following:First,the conversion of Gobi open land to alfalfa land was useful for decreasing significantly total salt in soil,nd salt content in the topsoil show a decreasing trend with the time extending of alfalfa growth.Second,the soil organism significantly decreasing after after planting crops,such as barley,wheat and flax;in contrast to that,planting alfalfa significantly increased soil organism especially the land with 8 year old or 25 year old alfalfa exhibited the highest soil organism compared to any other land types.Third,the total nitrogen and the ammonium nitrogen content gradually increased with the growth year of alfalfa extending in the 25 five years,and they were higher in the 25-year-old alfalfa land than that in other year-old alfalfa lands.Total nitrogen,ammonium nitrogen and nitrate decreased with the increase of soil depth in the profiles.so alfalfa had obvious effect on improving the nutrients and capacity recovery of saline land.Forth,plants have various effects to the land's PH value.PH value was dropped from 8.45 to 7.5 after cultured the alfalfa five years,but the PH value was gradually enhanced when growth with cropper,such as barley,wheat,flax.This result suggests that perennial alfalfa is more effective than general annual cropper. Fifth,Mg²⁺ was greatly declined when compared to other dissoluble cation;Na⁺ tended to move to the deeper layer;the concentration of Ca²⁺ became lower with the increment of depth of soil;and K⁺ decreased in the soil after the development of natural grassland.