The Relationship between Different Amounts of Irrigation and Changes of Soil Water Content in Populus×xiaozhuanica cv.‘popularis’ Plantation in Arid Area in lnner Mongolia

The Research on the relationship between different amounts of irrigation andchanges of soil water content in Populus×xiaozhuanica cv. ‘popularis' was conducted inthe arid area,Inner Mongolia. The results showed that :(1)the best irrigation amount was 7500 m3/(hm2 ·a);(2)the effective absorbed moisture soil layer with an irrigation of 1 500m3/(hm2·a),was 20～25 cm deep,while those with irrigation of 4 500,7 500 and 22 500m3/(hm2·a),were 50～70 cm, 50～100 cm, and 0～70 cm deep respectively;(3)in the soillayer of the former(0～20 cm deep),the maximum capacity of absorbed moisture was raised by 2.25,0.44,and 0.67 m3 respectively as compared with those plots with irrigation amount of 1 500,4 500,and 22 500 m3/(hm2·a);while in the soil layer of 0～30 cm deep of the former that was raised by 3.71,1.12,and 1.63 m3 as compared with those plots mentionedabove. The percentage of soil water content in field moisture capacity of the former ones was raised by 26.9%～23.3%,5.7%～5.0%,and 16.2%～7.1% respectively;The total soil water storage capacity of the former was raised by 310.4,456.6,and 1190.02 m3 respectively,The water shortage value(K) in the soil layer from 0～100 cm of the former was decreased by 23.3%～26.8%,5.1%～5.8%,and 7.2%～16.3% respectively;(4)finally themore the irrigation,the bigger the salt content.