PARENT SESSION
Oral Session #31: Plant Ecology: Gas Exchange.
Presiding: R. Montgomery
Tuesday, August 6. 8:00 AM to 11:30 AM. Cochise Meeting Room, TCC.
Effects of clipping and shading on soil respiration in tallgrass prairie.
Wan, Shiqiang*,1, Luo, Yiqi1, 1 Department of Botany and Microbiology, University of Oklahoma, Norman, OK
ABSTRACT- Carbon substrate is the ultimate control factors of soil respiration and its response to global climate change. We conducted a two-factorial experiment in an Okalhoma tallgrass prairie to examine the responses of soil respiration and its temperature sensitivity to clipping and/or shading, which reduced carbon supply to soil. On the diurnal basis four days after onset of the experiment, clipping, shading, and clipping plus shading treatments significantly decreased soil respiration in spite of their effects on soil temperature. Soil respirations in the clipped and/or shaded plots were 36-55% lower than that in the control plots within one week. Shading and clipping plus shading significantly, on average, decreased soil temperature by 0.8 and 0.7 degree in comparison of control plots whereas clipping had no effects. None of the three treatments affected soil moisture. Seasonal averages of soil respiration were significantly reduced by 31, 27, and 44% for the clipping, shading, and clipping plus shading treatments, respectively in comparison to the control treatment. Temperature sensitivity of soil respiration (Q10) decreased from 3.97 in the control plots to 3.49, 3.43, and 3.58 in clipped, shaded, and clipped plus shaded plots, respectively. Decreased temperature sensitivity of soil respiration indicates that ecosystems with lower carbon allocation to belowground and soil carbon content will be less sensitive to rising temperature under global warming.
KEY WORDS: Clipping, Shading, Soil respiration, Tallgrass Prairie