Study on soil respiration model coupled with temperature-moisture-biology factors

Soil respiration was measured with the enclosed chamber method in a fenced Leymus chinensis steppe in 2001 and 2002 and in a greenhouse in 2003. The temperature(T)-dependent exponential functions(Rs=ae^bT) could explain 41.1%~98.2% of the diurnal variation in soil respiration(Rs) in the field study. The coefficients a and b were different in the 15 exponential functions during the growing seasons in 2001 and 2002, which had good relationships with soil water content(R²=0.685) and aboveground biomass accumulation rate(R²=0.478), respectively. Therefore, the soil respiration model, Rs=(10.298W-34.149)e^{(0.005B+0.053)T}, was established with air temperature(T), soil water content(W) and aboveground biomass accumulation rate(B). Compared with the existing soil respiration models based on temperature-moisture interaction, the new established model could provide better fits with the measured values in four planting densities (30, 60, 90 and 120 plants/0.25 m²), R² ranging from 0.754 to 0.854. Therefore, the soil respiration model coupled with abiotic and biotic factors could more accurately simulate soil respiration at different temporal scales and better understand the processes.