围封对沙地草地的影响

The Effects of Enclosing on Sandy Grassland.

试验设群团状林围封草地、群团状林自由放牧地（放牧１年）和未围封天然草地３种处理，按照低平地、丘底、丘腹、丘顶４种立地类型分别进行植物种类、高度、盖度、密度、地上生物量（鲜、干重）、根量等调查和测定。结果表明：（１）围封育草能显著增加牧草的产量，加快草地植被的恢复，改善牧草的质量，对提高多年生禾本科和多年生豆科牧草的产量、百分含量效果明显，而杂草则相反；（２）围封育草在提高草群高度、密度、盖度上有明显的效果，地下根量也有明显的增加；（３）围封育草可培育优良的割草场，也能为草地的合理轮牧创造条件，它是一项投资少、见效快、简单易行的有效技术措施。

The experiment was carried out with 3 treatments, namely Enclosing of the grassland with groups of trees, Free-grazing (1 year) on the grassland with groups of trees, and Free-grazing on natural grassland. Plant species, height, coverage, density, above-ground biomass (fresh and dry weight), and root amount, etc. were observed on the flat low land, at the bottom of dune, in the middle of dune slope, and on the top of dune, seperatedly. The results showed that: (1) Enclosing significantly increased herbage yield, speeded up the recovery of grassland vegetation, improved herbage quality, increased the percentage and yield of periennial Graimineae and Legume species, and on the contrary weeds decreased. It can be drawn that enclosing speeded up the positive succession of natural grassland. (2) Enclosing increased the height, density, coverage, and root amount of plant population. (3) Enclosing could be taken as a way to establish high quality cutting grassland. It can also provide conditions for reasonable rotation grazing. Enclosing is a low-cost, simple way with quick longlasting effects.