摘要
以内蒙古自治区锡林浩特市为研究区,探讨了典型草原不同退化程度草地的植被-土壤系统氮储量的变化及差异,运用DNDC(Denitrification-Decomposition)模型对植被-土壤系统氮储量模拟并对结果进行了验证。结果表明,随着草地退化程度的加剧,土壤氮储量呈显著下降趋势(P【0.05),中度退化(MD)和重度退化(HD)样地较轻度退化(LD)样地土壤氮储量分别减少了7.74%和44.40%。不同退化程度样地的地上植物氮储量总体上呈现HD】MD】LD,与土壤氮储量的变化趋势相反;在生长季中,植物根系氮储量是逐渐增加的,且在生长季末表现为HD】MD】LD。植物-土壤系统中,土壤氮储量占总氮储量的比例高于根系和地上植物,占系统氮储量的95.05%~97.62%。DNDC模型在草原点位模拟土壤氮储量的效果比较好。
The variations of plant-soil system nitrogen storage in typical degraded steppe were measured in Xilin Hot City,Inner Mongolia.The values of plant-soil system nitrogen storage in different degraded grassland were also verified using DNDC( Denitrification-Decomposition) model.The results showed that soil nitrogen storage significantly reduced( P < 0.05) with the grassland degradation aggravated.Compared with light degradation grassland( LD),soil nitrogen storage in moderate( MD) and heavy degradation grassland( HD) decreased by 7.74% and44.40%,respectively.However,the nitrogen storage in plants varied in opposite way which decreased in the following order: HD > MD > LD.The nitrogen storage in roots gradually increased in the growing season and performed with the same order at the end of the growing season which was HD > MD > LD.The proportion of soil nitrogen storage in plant-soil system which ranged from 95.05% to 97.62% was higher than that of roots and plants nitrogen storage in plant-soil system.All of these results suggested that the DNDC model can accurately simulate the soil nitrogen storage in site in typical steppe.
出处
《草业科学》
CAS
CSCD
北大核心
2015年第3期311-321,共11页
Pratacultural Science
基金
国家重点基础研究发展计划项目(2014CB138803)
国家自然科学基金重点项目(41030535)
地表过程和资源生态国家重点实验室自由探索项目(2011-TDZY-102)
