关键词: 农田生态系统, 碳足迹, 空间分布, 河南省

Abstract: By using LI-8100 system, we measured the soil total and compartment respiration rates and the soil temperature and moisture contents at depth 5 cm in a Pinus tabuliformis plantation under four thinning intensities (0, CK; 20%, slight thinning; 30%, medium thinning; and 40%, intensive thinning) in Taiyue Mountain of Shanxi Province during growth season (from May to September, 2011). The soil respiration characteristics after selective cutting were studied, and the factors affecting the soil respiration were analyzed, aimed to approach the responses of the soil respiration to different forest management measures. As compared to CK, the soil respiration rates after selective cuttings were higher, with the peaks all appeared in August. Selective cutting increased the CO₂ flux, and the increment increased with increasing selective cutting intensity. The variation of the soil temperature and moisture conditions induced by selective cutting was one of the main reasons causing the variation of soil respiration. Soil temperature and humidity explained 60.5%-79.8% of the variation of soil respiration rates. The litter layer respiration and root respiration after selective cutting were the important components reflecting the soil respiration rates, while the mineral soil respiration had little effects. Our findings suggested that in order to reduce the forest soil surface CO₂ emission after selective cutting, a reasonable thinning intensity about 20% should be adopted.

Key words: carbon footprint, spatial distribution, Henan Province., farmland ecosystem