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Simulating Interactive Effects of Symbiotic Nitrogen Fixation, Carbon Dioxide Elevation, and Climatic Change on Legume Growth
Author(s) -
Yu Mei,
Gao Q.,
Shaffer M. J.
Publication year - 2002
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2002.6340
Subject(s) - nitrogen fixation , nitrogen , environmental science , biomass (ecology) , legume , nutrient , precipitation , atmospheric sciences , agronomy , carbon dioxide , photosynthesis , carbon dioxide in earth's atmosphere , chemistry , ecology , botany , biology , meteorology , physics , organic chemistry , geology
ABSTRACT The underlying mechanisms of interaction between the symbiotic nitrogen‐fixation process and main physiological processes, such as assimilation, nutrient allocation, and structural growth, as well as effects of nitrogen fixation on plant responses to global change, are important and still open to more investigation. Appropriate models have not been adequately developed. A dynamic ecophysiological model was developed in this study for a legume plant [ Glycine max (L.) Merr.] growing in northern China. The model synthesized symbiotic nitrogen fixation and the main physiological processes under variable atmospheric CO 2 concentration and climatic conditions, and emphasized the interactive effects of these processes on seasonal biomass dynamics of the plant. Experimental measurements of ecophysiological quantities obtained in a CO 2 enrichment experiment on soybean plants, were used to parameterize and validate the model. The results indicated that the model simulated the experiments with reasonable accuracy. The R 2 values between simulations and observations are 0.94, 0.95, and 0.86 for total biomass, green biomass, and nodule biomass, respectively. The simulations for various combinations of atmospheric CO 2 concentration, precipitation, and temperature, with or without nitrogen fixation, showed that increasing atmospheric CO 2 concentration, precipitation, and efficiency of nitrogen fixation all have positive effects on biomass accumulation. On the other hand, an increased temperature induced lower rates of biomass accumulation under semi‐arid conditions. In general, factors with positive effects on plant growth tended to promote each other in the simulation range, except the relationship between CO 2 concentration and climatic factors. Because of the enhanced water use efficiency with a higher CO 2 concentration, more significant effects of CO 2 concentration were associated with a worse (dryer and warmer in this study) climate.