林木超深栽在沙地造林中的应用效果分析

目的]探讨林木超深栽在沙地造林中的可行性,为提高干旱半干旱沙地造林效果提供依据。方法]在对永定河下游沙地不同深度土壤水分含量进行监测的基础上,以白榆为造林树种,开展了深根苗与普通苗的不同栽植深度﹝1m(超深栽),0.6m(深栽),0.3m(常规)﹞的造林试验。结果](1)沙地下层土壤的水分含量较高并相对保持稳定;(2)沙地林木超深栽显著提高了造林成活率40%以上(p0.01)。特别是使用林木深根苗进行超深栽时,即使在无灌水的条件下亦取得了很好的造林效果(成活率94%);(3)林木超深栽显著提高了苗木的高生长,但对胸径生长的促进作用仅在使用深根苗时观察到。结论]超深栽技术适用于干旱半干旱沙地造林,建议予以推广应用。

Effects of Extra-deep Planting on Survival and Growth of Seedlings in Sandy Soil

Objective] The feasibility of plantation establishment with extra-deep planting in a sandy soil was studied in order to provide support on increase of the survival rate of seedlings in arid and semi-arid sandy soil. Methods] The experiments were conducted in the lower reaches of Yongding River characterized by large areas of sandy soils. The seedlings were 2-year old Ulmus pumila L., some of which were cultivated with long roots(long-root seedlings). Others were raised with normal roots. The depths of planting were 1 m(extra-deep), 0.6 m(deep) and 0.3 m(usual). Soil water contents of different layers were measured monthly. Results] (1) Water content in deeper soil layers was higher and remained constant compared with that in shallower layers; (2) Extra-deep planting significantly increased the survival rate of seedlings by more than 40%. With extra-deep planting, the long-root seedlings showed reasonable survival rate and growth after transplanting(the survival rate was 94%), even without watering; (3) Extra-deep planting significantly increased seedling height, but significant increases in diameter at breast height were observed only for long-root seedlings. Extra-deep planting, especially with long-root seedlings, significantly increased seedling survival and growth. Conclusion] Extra-deep planting is suitable for plantation establishment in the sandy soils in arid and semi-arid areas, and should be applied.