【摘要】 <正> 河西走廊农田防护林带的建设,自从国务院成立西北、华北、东北防护林建设局以后,发展较快,在第一期工程期间(1978～1984年),河西走廊的武威、张掖、酒泉三个地区共造林142.47万亩,保存面积107.93万亩,保存率为75.7%。 从甘肃省来说三北防护林体系建设的重点工程是在河西走廊建立农田防护林,到目前为止;已营造了农田防护林33万亩,使385万亩耕地实观了农田林网化,占保灌耕更多还原

【Abstract】 330, 000 mu of shelter belts to protect farmland have been established in the Hexi Corridor, Gansu Province, covering about 8.5% of total arable(?) land. With the acceleration of shelter belts to protect farmland in the Hexi Corridor,interplanting of trees and grass in the shelter belts has developed in recent years. Tree species are mainly the(?)local ones such as poplars and P. (?)usbekistanca. Kom. cv.′Afghanica′. Forage species are mainly Caragana Korzhinskii and C. microphylla,and others are(?) alfalfa, winter (?)vetch and Astragalus, etc. Planting grass in the forest belts has an obvious effect upon the improvement of soil fertility. They are as follows. (1) the content of organic matter in soil in the forest belts planted with grass is 0. 32-4. 39%, while that in the forest belts without grass planted is 0.06-2.25%; (2)the amount of N content in soil in the forest belts with or without grass planted is extremely different (P<0.01); (3) the amount of hydrolyzable nitrogen content is greatly improved with a great significant difference (P<0.01); (4) the amount of available total N content is increased; and (5) there is no change in the amount of available P content. In order to establish a multiple benefit and comprehensive shelter belt ecosystem, to develop agriculture, forestry and animal husbandry in an allround way and to raise land productivity, planting grass in the shelter belts is a kind of productive measure being worth considering.更多还原