不同施肥模式对绿洲农田土壤微生物群落丰度与酶活性的影响

以中国科学院阜康荒漠生态系统国家野外观测研究站的长期定位试验为平台,利用荧光实时定量PCR(Real-time PCR)技术,对不同施肥模式下的土壤微生物群落丰度进行了测定,并分析了土壤酶活性。结果表明:与无肥处理(CK)相比,20年长期单施化肥(CF)或者化肥配施秸秆(CF/OM)处理均显著增加了土壤氨氧化古菌(AOA)与氨氧化细菌(AOB)的丰度。其中,土壤AOB最低增加了16倍,而AOA最多增加了3倍,表明AOB可能在原位土壤氨氧化过程中发挥了更为重要的作用。尽管CF/OM处理的作物产量与CF处理无显著差异,但该施肥模式在维持作物产量的同时,其土壤微生物主要类群(真核微生物、细菌、古菌)数量最大,土壤有机碳含量最高,大多土壤酶活性高于其他处理,表明化肥配施有机肥有利于保持土壤微生物多样性,对于提高土壤质量具有重要作用。

Effect of model of fertilization on microbial abundance and enzyme activity in oasis farmland soil

A 20-year field experiment on fertilization models, e.g. applications of inorganic fertilizer alone (CF) and inorganic fertilizer combined with wheat straw (CF/OM) was carried out to study responses of the soil in microbial abundance and enzyme activity in the National Field Research Station of Desert Ecosystem in Fukang, Xinjiang, China. Real-time quantitative polymerase chain reaction (Real-time PCR) analysis indicates that the abundances of soil ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) were significantly higher in Treatment CF and Treatment CF/OM than in the control (no application of fertilizer, CK). The population of soil AOB was increased at least by 16 times while that of soil AOA at best by 3 folds, which suggests that AOB play a more important role in in-situ nitrification. Although Treatment CF/OM did not differ much from Treatment CF in crop yield, but was the highest in population size of main soil microbial groups, content of soil organic carbon and activity of most soil enzymes when still sustaining crop yield, which indicates that combined application of chemical fertilizer and organic manure is conducive to maintenance of soil micro-biodiversity and plays an important role in improving soil quality for sustainable agriculture.