关键词: 燃烧试验, 土壤温度场, 采伐迹地, 长白落叶松人工林

Abstract: In the present study, we selected forest floor litters from three slope directions inMaolan Karst primary forest to investigate the distribution characteristics of litter stock, nutrientcontents (C, N, P and K) and their release rates of different decomposing layers. The results showed that: (1) Total litter stock was higher in north slope (0.568 kg·m^-2) than that in south slope (0.504 kg·m^-2) and northeast slope (0.295 kg·m^-2). Litter stocks in different layers arranged in the order of fresh litter layer (layer L>fragmented litter layer (layer F) > fullydecomposed layer (layer Y); (2) The C and K contents in different decomposing layers were in the order of layer L>layer F>layer Y, whereas the N and P contents were followed by the order of layer Y> layer F> layer L. (3) Total storage of litter C, N and K was in the order of north slope>south slope>northeast slope, and total litter P storage was the highest in the south slope, followed by north slope, and then the northeast slope. (4) The litter nutrient storage in layer Laccounted for 37.1% to 64.2% of the total nutrient storage, showing a decrease trend with theincreases of decomposition degrees. The release rates of the nutrient elements in layers L and F were the highest in the north slope, followed by the northeast slope and the south slope.Moreover, the release rates of C and K were higher than that of N and P. Our results indicated that the slope direction had a great influence on the chemical properties and decomposition rate oflitters. In general, litters in the north slope decomposed rapidly and the cycling time of nutrient elements was shorter than that in other slopes in the Karst primary forest.

Key words: harvested site, Larix olgensis plantation, combustion experiment, soil temperature field