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土壤有机质分解是陆地生态系统碳循环的重要环节,它不仅受温度和水分的影响,还对土地利用变化十分敏感.以中国科学院千烟洲生态试验站的柑橘园和湿地松人工林为对象,研究不同土地利用类型、温度(5、10、15、20和25℃)和水分(30%、60%和90%饱和含水量)对土壤碳矿化及其温度敏感性的影响.结果表明:土地利用类型、温度和水分对土壤碳矿化都具有显著影响,且各因素间存在显著的交互效应.柑橘园和湿地松人工林土壤碳矿化速率均与温度呈正相关,60%饱和含水量处理下土壤碳矿化速率最高.在相同的温度和水分处理下,柑橘园土壤碳矿化量显著高于湿地松林.土地利用类型和水分对土壤碳矿化温度敏感性(Q10)具有显著影响.培养7和42 d,土壤碳矿化的温度敏感性随水分升高而上升;柑橘园温度敏感性高于湿地松林,且水分越高差异越明显.包含温度和水分的双因素模型可以很好地模拟土壤碳矿化对温度和水分的响应,温度和水分共同解释土壤碳矿化变异的79.9%~91.9%.
Soil organic matter decomposition is an important part of the carbon cycle in terrestrial ecosystems, and it is not only affected by temperature and water but also is very sensitive to land-use changes.According to the citrus orchards and slash pine plantations at Qianyanzhou Ecological Experimental Station of Chinese Academy of Sciences, The effects of different land use types, temperature (5, 10, 15, 20 and 25 ℃) and moisture (30%, 60% and 90% saturated water) on soil carbon mineralization and its temperature sensitivity were studied.The results showed that: The land use type, temperature and moisture had a significant effect on soil carbon mineralization, and there was a significant interaction between the factors.Carbon mineralization rate of citrus orchard and Pinus elliottii plantations was positively correlated with temperature, and the 60% saturated water content Under the same temperature and moisture treatment, the soil carbon mineralization of citrus orchards was significantly higher than that of Pinus elliottii forest land use types and water content had a significant effect on soil carbon mineralization temperature sensitivity (Q10) The temperature sensitivity of soil carbon mineralization increased with the increase of water temperature at 7 and 42 d incubation, and the temperature sensitivity of citrus orchard was higher than that of the Pinus elliottii plantation, and the higher the water content, the more obvious the difference was.The two-factor model The model can well simulate the response of soil carbon mineralization to temperature and moisture, and the temperature and moisture together explain 79.9% -91.9% of the soil carbon mineralization variation.