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研究侵蚀土壤有机质矿化及其温度敏感性(Q10)对深入认识水土流失地区土壤有机碳动态变化具有重要意义。该文以福建省长汀县河田镇严重侵蚀区的裸露红壤为研究对象,通过测定不同培养温度(10℃、20℃和30℃)下的土壤有机碳矿化速率、培养过程中微生物生物量碳(MBC)和可溶性有机碳(DOC)含量的变化,探讨了温度对严重侵蚀红壤有机碳矿化特征的影响及其Q10。结果表明:温度对严重侵蚀红壤有机碳矿化具有显著影响,温度越高土壤有机碳矿化速率和矿化率越高;培养过程中土壤有机碳累积矿化量与MBC显著正相关,与DOC极显著负相关,说明微生物生物量和可利用碳含量显著影响土壤有机碳的矿化。尽管严重侵蚀红壤有机碳含量仅为1.54 g·kg–1,但培养180天的土壤有机碳的累积矿化率高达22.2%–33.3%,表明侵蚀红壤有机碳容易被矿化。严重侵蚀红壤在10–20℃时的Q10值为1.41,20–30℃时Q10值下降到1.06,土壤有机碳质量低是导致Q10值较低的重要原因,而严重侵蚀区的红壤长期裸露使微生物对高温产生适应性是高温时Q10值接近1的重要原因。因此,在未来气候变暖的趋势下,恢复植被覆盖对减少严重侵蚀红壤有机碳矿化损失具有重要意义。
Studying the mineralization of organic matter and its temperature sensitivity in eroded soils (Q10) is of great importance for understanding the dynamic changes of soil organic carbon in soil erosion areas. In this paper, the red soil in the seriously eroded area of Hetian Town, Changting County, Fujian Province was selected as the research object. By measuring the rate of soil organic carbon mineralization under different cultivation temperatures (10 ℃, 20 ℃ and 30 ℃), the microbial biomass Carbon (MBC) and soluble organic carbon (DOC) content in soils, and discussed the effect of temperature on the mineralization of organic carbon in severely eroded red soil and its Q10. The results showed that temperature had a significant effect on the mineralization of organic carbon in severely eroded red soils. The higher the temperature was, the higher the mineralization and mineralization rates of soil organic carbon were. Significantly negative correlation, indicating that microbial biomass and available carbon significantly affect the mineralization of soil organic carbon. Although the organic carbon content was only 1.54 g · kg-1 in severely eroded red soil, the cumulative mineralization rate of soil organic carbon up to 22 days was 22.2% -33.3% after 180 days incubation, indicating that the organic carbon in eroded red soils is easily mineralized. The Q10 value of the heavily eroded red soil was 1.41 at 10-20 ℃, and the Q10 value was decreased to 1.06 at 30-30 ℃. The low soil organic carbon was the major reason for the low Q10 value. However, Microbial adaptation to high temperatures is an important reason for the Q10 value approaching 1 at high temperatures. Therefore, under the trend of future climate warming, the restoration of vegetation cover is of great significance to reduce the mineralization loss of organic carbon in severely eroded red soils.