论文部分内容阅读
以河北省木兰围场国有林场管理局北沟林场内5种不同密度的华北落叶松人工林为对象,研究林分密度对土壤理化性质的影响,结果发现:林分密度不同程度地影响土壤理化性质。当株数密度为660株/hm2时,土壤的质量含水量、全N及全K含量均保持在一个相对较高的水平;当株数密度从740株/hm2增加到2 000株/hm2时,0～20cm土层的土壤密度先减小后增大,而土壤质量含水量、土壤有机质和全N含量表现出相反的趋势;20～60cm土层的土壤密度与0～20cm土层的变化情况相同,而土壤质量含水量和土壤速效K含量则持续降低,土壤有效P含量呈现出增大趋势;当株数密度达到2 000株/hm2以上时,林地土壤的pH值降低,呈现明显的酸化趋势。过大的林分密度可能导致华北落叶松人工林地土壤酸化与土壤水分、有机质、N和K元素的加速消耗。从维持林地土壤健康的角度,建议将华北落叶松人工林地的林分密度控制在1 500株/hm2左右并且不能超过2 000株/hm2。
Five species of Larix principis-rupprechtii plantations with different densities in Beigou Forest Farm of Beigou Forest Farm in Mulanweizi Farm of Hebei Province were used to study the effects of stand densities on soil physical and chemical properties. The results showed that: Stand Density affected soil physical and chemical properties to varying degrees . When the plant number density was 660 plants / hm2, the soil mass water content, total N and total K content were maintained at a relatively high level. When the plant density increased from 740 plants / hm2 to 2000 plants / hm2, 0 The soil density of ~ 20cm soil layer first decreased and then increased, while the soil water quality, soil organic matter and total N content showed the opposite trend. The soil density of 20 ~ 60cm soil layer was the same as 0 ~ 20cm soil layer While soil available water content and soil available K content continued to decline, while soil available P content showed an increasing trend. When the plant number density reached more than 2 000 plants / hm 2, the soil pH value decreased, showing a clear acidification trend. Too large stands density may lead to soil acidification and soil moisture, organic matter, N and K elements in Larix principis-rupprechtii plantation accelerated consumption. In order to maintain the soil health of forestland, it is suggested that the stand densities of Larix principis-rupprechtii can be controlled to about 1 500 plants / hm 2 and can not exceed 2 000 plants / hm 2.