民勤境内梭梭、柠条人工混交造林效果日趋低下.以半固定沙丘、丘间滩地、盐碱地5a生梭梭、柠条人工混交林为对象,样地法调查土壤理化性质,及造林树种保存率、冠幅和生物量.结果表明:1)半固定沙丘、丘间滩地梭梭保护率＞78％,显著优于盐碱地,丘间滩、盐碱地的柠条保存率＞50％,明显优于半固定沙丘;2)梭梭枝冠生长和生物量积累均以半固定沙丘为优,以盐碱地为劣,柠条则以丘间为优,以半固定沙丘为劣;3)梭梭适应半固定沙丘风沙环境而忌避盐碱,柠条则适应丘间地土壤黏重环境而忌避风沙,相对于梭梭较耐盐碱.分析认为,3种立地上梭梭、柠条混交造林成林效果差异明显,不应一味使用相同混交模式营造防风固沙林.

梭梭是我国重要的造林树种,对外界环境适应能力很强,主要优点是抗旱、耐高温和耐盐碱,根系比较发达,能起到很好防风固沙效果,适合荒漠化治理.利用梭梭造林能增加地表植被覆盖率,并且改善生态环境,尤其在干旱地区,人工栽植梭梭生长速度快,防风固沙效果好,是造林最佳选择.

In the lower reaches of the Shiyang River, the artificially fixed shrubbery appears to decline.The sand-fixing shrubs constructed in 2003 and 2006 were investigated by sample plot method in Datan branch of Shiyang River Forestry Farm. The sand-fixing effect was evaluated by stand height, average canopy width and tree decay index. The results showed that in 2003 and 2006, the four types of stands were the same,and the mixed Caragana korshinskii forest with the same hole significantly reduced the decay of Haloxylon ammodendron. It was concluded that when the stand age was more than 16 years, the sand-fixation effect of Haloxylon ammodendron pure forest and Haloxylon ammodendron-Caragana korshinskii mixed forest was the same. The sand-fixation effect of the Haloxylon ammodendron-Caragana korshinskii mixed forest was more stable than that of the Haloxylon ammodendron pure forest.

武威市北部干旱沙区常规造林成效低.采取多树种搭配、精选苗木、ABT生根粉泥浆蘸根、大苗深栽、1穴多株、穴内多种、2次整地3次灌水、截干平茬、造林前后防治鼠兔害等集成技术,大规模治沙造林.结果表明,4年平均成活率85.6％,较常规造林提高约10百分点;3年生梭梭株高69～135 cm,地径0.8～1.3 cm,新梢长30～42 cm,防风固沙效果明显;流动沙丘成活率高而且稳定,丘间低地成活率年际变化较大,相差13百分点.集成技术治沙造林成活率、保存率均高于合格标准,技术成熟,可以推广应用于武威市北部干旱沙区.