Nitrogen storage variations in typical steppe during grassland degradation progress——A case study of typical steppe in Xilin Hot City,Inner Mongolia

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 (PMD>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.