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以中国科学院海伦农田生态系统国家野外科学观测研究站的长期定位试验为平台,研究不同植被覆盖下土壤微生物量碳在作物生长季节的动态变化及其与土壤有机碳的相关性。结果表明,微生物量碳的变化趋势呈单峰型曲线,7月19日达到峰值,9月3日降到最低。不同植被覆盖下,土壤微生物量碳的平均含量以草地最高,作物覆盖居中,而裸地最低,三种农作物大豆、玉米和小麦在生长旺盛期达到最大值,分别为452.26 mg kg-1,371.05 mg kg-1,484.98 mg kg-1。不同植被覆盖下,不同土层有机碳含量的变化趋势为:0~10 cm>10~20 cm,其中0~10 cm土壤有机碳和微生物量碳的相关性显著(P<0.05)。微生物熵的变化趋势大致为:草地>小麦>玉米>大豆>裸地,说明长期自然恢复有利于土壤有机碳向微生物量碳的转化,有利于改善土壤质量。
Based on the long-term experiment of the National Field Observatory at Helen Agro-ecosystems, Chinese Academy of Sciences, the dynamic changes of soil microbial biomass carbon during crop growth season and its correlation with soil organic carbon under different vegetation cover were studied. The results showed that the trend of microbial biomass carbon showed a unimodal curve, reaching its peak on July 19 and dropping to the lowest on September 3. Under the different vegetation cover, the average content of soil microbial biomass carbon was the highest in grassland, the middle in crop coverage, and the lowest in bare land. The three crops, soybean, corn and wheat reached their maximum during the vigorous growing period, reaching 452.26 mg kg-1,371.05 mg kg -1,484.98 mg kg-1. Under different vegetation cover, the trend of SOC in different soil layers was 0 ~ 10 cm> 10 ~ 20 cm, and the correlation was significant between 0 ~ 10 cm soil organic carbon and microbial biomass carbon (P <0.05). The trends of microbial entropy change are as follows: grassland> wheat> corn> soybean> bare land, indicating that long-term natural recovery is conducive to the conversion of soil organic carbon to microbial biomass carbon, which is good for soil quality improvement.