Estimating the Net Primary Productivity of Grassland in Poyang Lake Wetland with a Modified Atmosphere-Vegetation Interaction Model

要旨

This paper presents a modified land-atmosphere interaction process model to estimate the net primary productivity (NPP) of grassland in Poyang Lake wetland, China. The model is developed on the basis of an atmosphere-vegetation interaction model (AVIM), with two important improvements reflecting the impact of water level of wetlands on plant growth. Thus, a new module that estimates dynamic changes of the water level is proposed in the physical process model (LPM) component and another important controlling factor of plant physiological processes is introduced in the plant growth model (PLT) component. The daily NPP of grassland in 2006 was estimated using the modified AVIM and agreed well with the validation datasets of the observed biomass. According to the results, the NPP of grassland varies from 1250 to 2000 DM•m-2•a-1. The correlation analysis shows a significant relationship between NPP and the grassland elevation, and the NPP is highest in an elevation zone of 14.0~14.5 m. Another significant relationship between NPP and temperature or humidity was also found. In spring, the plant growth is affected by temperature, whereas in fall, it is mainly affected by humidity.