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农田防护林具有明显的防止风沙危害、改善小气候、提高作物产量的作用。但林带也有胁地作用。杨树(本文中一般指二白杨Populus ni-gra var.the(?)estina×P.Simonii,下同)是河西地区的乡土速生树种,适应性强,繁殖容易,成林成材快,深受群众喜爱,在营造农田防护林时被广泛采用;枣树(Zizyphus jujuba Mi-ll.)是我国北方的重要经济树种,抗寒抗旱能力较强,耐瘠耐碱,容易栽培,管理简便,在
Farmland shelterbelts have the obvious function of preventing wind and sand hazard, improving microclimate and increasing crop yield. However, the belt is also threatening effect. Poplar (Populus ni-gra var. The (?) Estina × P.Simonii in this paper is the native fast-growing tree species in Hexi region, which has strong adaptability, easy propagation and rapid succession) Which are widely used in the construction of farmland shelterbelt. Zizyphus jujuba Mi-ll. Is an important economic species in the north of our country. It has strong ability of drought resistance and drought resistance, alkali resistance, easy cultivation and easy management.