PARENT SESSION
Poster Session #5: Soil Ecology.
Monday, August 6, 2001. Presentation from 10:30 AM to 12:00 PM. Exhibition Hall

Response of soil respiration to watering treatment in tallgrass prairie.

Liu, Xiaozhong¹, Wan, Shiqiang¹, Luo, Yiqi¹, ¹

ABSTRACT- Soil respiration is an important source of C in the ecosystem. Modeling predictions of ecosystem C cycling require both temperature and moisture functions of soil respiration. Temperature functions of soil respiration can be well described while our understanding of moisture functions is strongly limited. We conducted a field experiment in a tallgrass prairie to characterize the effect of soil moisture on soil respiration in the dry season of 2000. Soil respiration showed a dramatic increase right after watering treatments followed by a gradual decrease. The time courses of soil respiration can be well described by R = R₀ + ate^-bt, where R is soil respiration, R₀ is soil respiration before watering, t is time, and a and b are coefficients. The coefficient a and b were highest at 10 mm water, and decreased with the increase of water, to the lowest at 300 mm water. The relationship between soil respiration and moisture can be described by an equation R = -0.0088m² + 0.436m - 0.336, where R is soil respiration and m is soil moisture. We did a similar experiment with soil columns without plant materials in the laboratory. Soil respiration showed similar patterns in response to watering. The results in this study indicated that the moisture effects of soil respiration could be described by the exponential equation.

KEY WORDS: soil respiration, soil moisture, Tallgrass prairie, exponential equation