榆林市风沙区水土保持植物配置模式初探

Preliminary study on the disposition patterns of soil and water conservation plants in Yulin Sand-drift Area

榆林市风沙区是我国西北黄土高原地区水土流失最为严重的地区之一,合理配置水土保持植物措施,可有效降低风沙危害、减少入黄泥沙、改善生态环境。根据该区立地条件类型的划分,以小叶杨、沙柳、沙棘、柠条、爬地柏等乔灌木为主,提出4种水土保持植物配置模式:1)对于平缓沙丘及丘间低地,采用迎风坡前方下部种植灌木或每隔1个沙丘进行乔灌混交的种植模式;2)对盖沙土梁峁坡及沟坡,采用在沟坡配置灌木纯林,梁峁坡为乔灌混交的模式;3)沟谷地川滩地地势平坦,坡度较小,以农田防护林带建设为主;4)盐碱土河滩地主要选择耐盐渍的树种和草种,与河水主流方向成30°～45°交角栽植林带,采取行间混交或带状混交。这些水土保持植物配置模式可为同类地区的水土保持植被建设提供借鉴。

Yulin Sand-drift Area is one of the most significantly eroded areas on Loess Plateau in Northwest China. However, rational disposition pattern of soil and water conservation plants can effectively reduce sand storms and sediment into the Yellow River and improve the ecological environment. Four disposition patterns of soil and water conservation plants are designed according to different site conditions. The main species of plants used in these patterns include Populus simonii, Salix psammophila, Hippophae rhamnoides, Caragana korshinskii, Sabina vulgaris and other arbors and shrubs. The corresponding pattern for gentle dunes and interdune lowlands is to grow shrubs on the lower windward slope or to grow arbors and shrubs mixed together on every other dune. For sandy hills, pure shrubberies are for dales while mixed forests of arbor and shrub are for ridges. For river beaches and strands which are relatively flat, with small slope, farmland shelterbelts are the most suitable mode. For flood lands with saline-alkali soil, salt-resistant tree and grass species are preferred. The plants should be planted in a mixed way- mixed afforestation either by line or by strip at an angle of 30~ -45~ to the river mainstream direction. It is hoped that this study on disposition patterns of soil and water conservation plants in Yulin Sandy-drift Areas could shed light on disposition pattern design for soil and water conservation vegetation construction of other sandy-drift area facing similar problems.