摘要
针对我国青藏高原草地大面积退化及由此引发的一系列生态环境问题，从土壤生态功能恢复和区域可持续发展的角度出发，将原生高寒嵩草草甸封育系统作为对照，研究了土地退化对土壤碳氮含最的影响，检验了不同人工重建措施（3个人工种植处理：混播、松耙单播、翻耕单播和1个自然恢复处理）对土壤碳含量的相对影响程度。研究结果如下：原生植被封育处理每平方米土壤平均碳、氮含量分别为7．47kg和0．647kg，而重度退化地碳、氮含量分别为3．67和0．448kg·m^-2．可以推算，由于土地退化而造成的土壤（0-20cm层）碳氮丢失量分别为3．80kg·m^-2和0．199kg·m^-2，即高寒草甸土地退化导致0～20cm土壤层中50．87％的有机碳和30．75％的氮流失，可以看出高寒草甸土壤退化后流失的碳比氮多；混播处理、松耙单播处理、翻耕单播处理和自然恢复处理土壤单位面积有机碳含量分别是原牛植被土壤有机碳的70．5％，69．0％，49．0％和80％，单位面积氮含量分别是原生植被土壤全氮的86．9％，88．7％，71．1％和91．7％。但是，与重度退化地相比，除翻耕单播处理外，其它恢复重建措施均能部分恢复系统的碳氮含量，因此，将重度退化地进行自然恢复或松耙混播重建多年生植被可以作为系统固定碳（碳汇）的一个途径。
Grassland degradation are widespread and severe in Qinghai-Tibetan Plateau. In order to explore management approach for sustainable development of soil quality, we study the effect of land degradation on soil C and N content, examine the relative influence of various rehabilitation practices （three seeding treatment and a non-seeded natural recovery treatment） on soil C and N content in early secondary succession. The research was conducted on alpine meadows in Dari county of Qinghai Province. The resuits showed： In the YF treatment, soil C and N content were 7.47 g·m^-2 and 0.647 g·m^-2 in the 0-20 cm depths, respectively. The total C and N content in soil of the SDL treatment were 3.67 and 0.448 g·m^-2, respectively. So, loss of soil organic C and total N in per unit area （m^-2） amounted to 3.8 and 0.199 kg on alpine meadow soil at 0-20 cm layers during land degradation, respectively. Namely, land degradation leads to loss of 50.87% C and 30.75% N in originally native ecosystem on alpine meadow. The soil C content in the HB, DBB, DBF and NR treatment was 70.5 per cent, 69.0 per cent, 49.0 per cent and 80.0 per cent, respectively, of that in the YF while the soil N content in the that was 86.9 per cent, 88.7 per cent, 71.1 per cent and 91.7 per cent, respectively, of that in the YF. But Compared with the severely degraded land, all rehabilitation measures except DBF treatment may in part recover C and N content of ecosystem. So, restoring the severely degraded lands by HB or NR treatments to perennial vegetation is an alternative approach to sequestering C in former degraded system.
出处
《生态环境》
CSCD
北大核心
2006年第2期362-366,共5页
Ecology and Environmnet
基金
青海省科技攻关项目(2002-N-118)
国家"十五"科技攻关重大项目(2001BA606A-02)
关键词
高寒草甸
土地退化
恢复重建
土壤碳氮含量
alpine Kobersia meadow
land degradation
rehabilitation
soil C and N content
