[Dynamic simulation of photosynthate allocation in maize organs based on functional equilibrium hypothesis].

By using the 2004-2008 observation data of maize biomass and related environmental factors from the Jinzhou Agricultural Ecosystem Research Station of Shenyang Institute of Atmospheric Environment under China Meteorological Administration (CMA), the Friedlingstein model was validated and tested at station site and daily time scales. A model of soil available nutrient coefficient for maize field was developed, based on fertilization, soil temperature, and soil available water; and a daily time scale maize photosynthate allocation model was built, according to the functional equilibrium hypothesis. Comparing with Friedlingstein model, the daily time scale maize photosynthate allocation model could give more accurate simulation of photosynthate allocation in maize root, stem, and leaf, and provide technical support for accurate simulation of daily net primary productivity of maize agro-ecosystem.

[Characteristics and numerical simulation of surface albedo in temperate desert steppe in Inner Mongolia].

Based on the meteorological and biological observation data from the temperate desert steppe ecosystem research station in Sunitezuoqi of Inner Mongolia during growth season (from May 1st to October 15th, 2008), the diurnal and seasonal characteristics of surface albedo in the steppe were analyzed, with related model constructed. In the steppe, the diurnal variation of surface albedo was mainly affected by solar altitude, being higher just after sunrise and before sunset and lower in midday. During growth season, the surface albedo was from 0.20 to 0.34, with an average of 0.25, and was higher in May, decreased in June, kept relatively stable from July to September, and increased in October. This seasonal variation was related to the phenology of canopy leaf, and affected by precipitation process. Soil water content (SWC) and leaf area index (LAI) were the key factors affecting the surface albedo. A model for the surface albedo responding to SWC and LAI was developed, which showed a good performance in consistent between simulated and observed surface albedo.

[Biomass allocation of Leymus chinensis population: a dynamic simulation study].

Based on a greenhouse simulation experiment, this paper studied the dynamics of the above- and below-ground biomass of Leymus chinensis populations with four planting densities (120, 240, 360 and 480 plants x m(-2)). The results showed that the above- and below-ground biomass of L. chinensis populations had an increasing trend with the growth, and increased with increasing planting density. However, the relative growth rates (RGRs) of the above- and below-ground biomass did not show significant difference among the L. chinensis populations. The ratio of root to shoot (RRS) of the L. chinensis populations increased with their growth, but did not show significant difference among the planting densities, implying that environmental factors were the controlling factors for RRS. There existed significant power function relationships between the above- and below-ground biomass of L. chinensis individuals and populations, but the power function indices and coefficients varied with the planting density. It was suggested that the difference of microenvironment resulted from resources competition could induce the changes of L. chinensis RRS, and the latter could be used as a reference to quantitatively study the allocation of photosynthetic products.