文献类型：会议论文

英文题名：The degradation of soil fertility in pure larch plantations in the northeastern part of China

作者：Liu, SR Li, XM Niu, LM

通信作者：Liu, SR[1]

机构：[1]Chinese Acad Forestry, Inst Forest Ecol & Environm Res, Beijing 100091, Peoples R China;[2]Forestry Bur Jianping, Jianping Cty 122400, Liaoning Prov, Peoples R China

会议论文集：Workshop on Degradation of Forest Sites and the Possibility of Their Recovery at the XXII IUFRO World Congress

会议日期：1995

会议地点：TAMPERE, FINLAND

语种：英文

外文关键词：soil degradation; larch plantation; nutrient cycling; decomposition; understorey vegetation

年份：1998

摘要：Soil degradation was found in first generation of Dahurian larch (Larix gmelinii (Rupr) Rupr.) plantations in northern China and also in plantations of other larch species such as Larix olgensis and Larix leptolepis in the same area. Soil degradation in pure larch plantations may be exacerbated in the second rotation under continuous cropping and was accompanied by obvious concomitant decrease in tree growth. A study on nutrient cycling revealed that poor quality of larch litter, which decomposed very slowly, was a key factor leading to soil degradation and decline in tree growth in pure larch plantations. The accumulation of forest floor litter in similar to 20-year-old pure larch stands was 23-28 ton ha(-1) and this was higher than 9-16 ton ha(-1) in virgin mixed Korean pine/broad-leaf forests. Larch litter took 4.4 years to mineralise, whereas angiosperm litter lash, birch and poplar) in a pure larch stand took only 0.9-2.4 years. The progressive accumulation of litter on the forest floor acted as a heat-isolating layer which inhibited thermal conduction and decreased soil temperature and limited soil microbial activities. Consequently, degradation of soil fertility occurred and this was exacerbated after two or more rotations under continuous cropping. The role of the understorey vegetation was significant in nutrient recycling and maintaining sustainable soil fertility in larch plantations. A low-cost, effective way to prevent soil degradation in pure larch plantations is to develop mixed stands formed either by creating a mixture with broad-leaved trees or by introducing understorey vegetation (herbs and shrubs). Large areas of man-made, pure larch stands should be replaced by many small patches of different. uneven-age stands and crop rotation with different tree species should be adopted instead of continuous larch cropping. (C) 1998 Elsevier Science B.V. All rights reserved.