Qc. Zeng et al., MAXIMUM SIMPLIFIED DYNAMIC-MODEL OF GRASS FIELD ECOSYSTEM WITH 2 VARIABLES, Science in China. Series B, Chemistry, life sciences & earth sciences, 37(1), 1994, pp. 94-103
Based on general consideration and analysis, a maximum simplified dyna
mic model of grass field ecosystem with a single species is developed.
The model consists of two variables: grass biomass of grass field per
unit area and soil wetness, and is suitable for describing their mutu
al interaction. Other factors such as physical-chemical characteristic
s of soil, precipitation, irrigation, sunlight, temperature and consum
ers, are taken into account as parameters in the dynamical system. Qua
litative analysis of the model shows that grass biomass of a possible
ecological regime is determined by the stable equilibrium state of the
dynamical system. For the grass species interacting weakly with soil
wetness the grass biomass continuously depends on the precipitation. W
hile, for a species interacting strongly with soil wetness, grass biom
ass is abundant if precipitation is larger than some critical value; o
therwise, it becomes a desertification regime with very little or even
zero grass biomass. The model also shows that there exists a critical
(maximum) consuming value, the grass field with abundant biomass can
be restored if the consuming is less than the critical value; otherwis
e, it becomes desertification.