摘要
连续3a采用定位观测和临时调查的方法对因放牧所引起的地表物理变化、水土流失、幼林遭受伤害程度等方面进行了较为系统的研究,结果表明:牧期牛在牧场中对林地地表的土壤物理性状的影响有一个渐变过程,并呈累积值,当土壤密度达到1 3g·cm-3时呈相对衡定状态。牧场中水土流失与放牧强度呈正比,最大差值试验区与对照区的比可达29 7倍。通过对本溪、丹东两市混牧林的抽样调查表明:牛对幼树的伤害途径主要为践踏和耍角,但通过分析也证明,当落叶松幼林平均高度为2 0m时可进行适度放牧,但伤害指数不能高于50。当落叶松幼树平均高度在2 0m以下及坡度大于30°时应划为禁牧区,人工林平均高3m以下不应作"卧牛场"。
Through 3year fixed and temporary investigation, the changes of the earth's surface, loss of soil and water, and hurt degree of young forests were systematically studied. The results indicated that the cattle apparently destroyed the physical properties of surface soil. The degree, however, was constant when the bulk density of soil was 13g·cm-2. The loss of soil and water is positively correlated with the grazing intensity in grazing forest and the ratio of plot to contrast is 297:10 The spot check in Benxi and Dandong showed that the ways of cattle hurting seedlings are mainly trample and horning. The analysis also proved that the grazing can be done in larch forests which mean tree height is over 20 meters,but the hurt indices must be less than 50When the mean height of larch young sapling is lower than 20 m with the slope over 30°,the stand should be treated as pastureforbidden area,while when the mean height of plantation is below 3 m,the forest land should not used as for cattle to rest.
出处
《林业科学研究》
CSCD
北大核心
2003年第3期312-318,共7页
Forest Research
基金
辽宁省科技厅研究项目(1996-1999年)
编号1997 75
