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研究土壤矿化过程中土壤微生物群落结构的变化特征,对深入理解土壤中物质转化和养分迁移机理、提高土壤质量具有重要意义.因此,本文以宁南山区典型的两种人工灌木林-柠条和山桃林地土壤为研究对象,采用PVC顶盖埋管法进行1年的原位矿化实验,每隔2个月采样测定土壤基本理化性质和磷脂脂肪酸(Phospholipid fatty acid,PLFA)含量,探讨土壤在矿化过程中微生物群落结构的变化特征.结果显示:土壤矿化过程中,柠条林地土壤有机碳、全氮、硝态氮、铵态氮和土壤含水率显著高于山桃林地(p<0.05);两种灌木林地有机碳含量在矿化240 d和360 d时较低,显著小于其他矿化时期(p<0.05),硝态氮、铵态氮含量均在矿化240 d时最低,全氮和土壤pH随时间变化不显著.柠条林土壤各菌群PLFA含量高于山桃林土壤;两种土壤各菌群PLFA随矿化时间大体呈现出夏季>春、秋季>冬季的趋势,且差异显著(p<0.05);土壤细菌与真菌、革兰氏阳性(GP)和阴性菌(GN)的PLFA比值差异显著(p<0.05),柠条林土壤细菌与真菌PLFA比值随矿化时间呈现出夏、秋季>春、冬季的趋势,而山桃林土壤细菌与真菌PLFA比值在冬季最低,两种土壤革兰氏阳性和阴性菌PLFA比值在春季最大.PLFA主成分分析表明,柠条和山桃林土壤微生物群落结构不同,并且土壤微生物群落结构随矿化时间逐步发生变异,微生物结构的变化主要由以16∶0、16∶1ω9c、16∶1ω9t、17∶0、10Me18∶0和cy19∶0所代表的细菌及以18∶2ω9,12c所代表的真菌的变化引起.土壤微生物PLFA与土壤有机碳、硝态氮和土壤含水率显著相关,与土壤pH值不相关,说明土壤微生物PLFA与土壤理化性质联系紧密.
Studying the characteristics of soil microbial community structure during the process of soil mineralization is of great significance for understanding the mechanism of soil nutrient conversion and nutrient migration and soil quality improvement.Therefore, in this paper, two typical shrubs, And Picea mongolica soil, a one-year in-situ mineralization experiment was carried out using PVC roof buried pipe method. The soil physical and chemical properties and phospholipid fatty acid (PLFA) content were determined every two months. The results showed that the contents of soil organic carbon, total nitrogen, nitrate nitrogen, ammonium nitrogen and soil moisture were significantly higher in the soil mineralization process than those in the pelagic forests (p < 0.05). The contents of nitrate nitrogen and ammonium nitrogen in two shrubbery forests were lower at mineralization 240 days and 360 days than those during other mineralization periods (p <0.05) , Total nitrogen and soil pH did not change significantly with time.The content of PLFA in soil of Caragana korshinskii forest was higher than that in Shantaolin soil.The PLFA of each soil microbial community in two kinds of soil generally showed the trend of summer> spring and autumn> winter with mineralization time , And the difference (P <0.05). The PLFA ratios of soil bacteria to fungi, Gram-positive bacteria and GN were significantly different (p <0.05). The ratios of soil bacteria to fungi PLFA in Caragana korshinskii The spring and winter trends of summer and autumn> spring and winter, while the PLFA ratio of bacteria and fungi in the soil of Santo forest was the lowest in winter, and the PLFA ratio of Gram-positive and -negative bacteria in both soil was the highest in spring.PLFA principal component analysis showed that Caragana korshinskii and Peach Soil microbial community structure is different, and soil microbial community structure gradually changes with the mineralization time, microbial structure changes mainly by 16: 0,16: 1ω9c, 16: 1ω9t, 17:0,10Me18:0 and cy19:0 Represented by bacteria and 18:2ω9,12c represented by changes in fungi caused by soil microbial PLFA and soil organic carbon, nitrate nitrogen and soil moisture was significantly correlated with the soil pH is not relevant, indicating that soil microbial PLFA and soil Physical and chemical properties are closely linked.