不同管理措施对高寒草甸土壤微生物量的影响研究

采用氯仿熏蒸浸提法对玛曲高寒草甸4种管理措施(不围栏、围栏、围栏+施肥、围栏+补播)土壤微生物量碳(SMBC)、氮(SMBN)和磷(SMBP)连续4年(2011-2014年)变化动态进行研究,结果表明,1)同一年份,不同管理措施,相同空间层次,土壤微生物量表现为:围栏+补播>围栏+施肥>围栏>不围栏(0~20 cm)和围栏+施肥>围栏+补播>围栏>不围栏(20~40 cm);同一年份,相同管理措施,不同空间层次(0~20 cm,20~40 cm),土壤微生物量表现为0~20 cm>20~40 cm, 一般前者为后者的1.22~3.39倍。2)不同年份,相同管理措施,相同空间层次(0~20 cm,20~40 cm),除不围栏(0~20 cm)SMBC外,土壤微生物量年际变化表现为2011至2012年上升至最大值,之后下降;不同年份,相同管理措施,不同空间层次(0~20 cm,20~40 cm),0~20 cm土壤微生物量年际变化幅度大于20~40 cm。土壤微生物量与气温呈负相关关系,土壤微生物量与降水量呈显著正相关关系。运用综合指数法计算出不同管理措施下土壤质量综合指数,其值排序为:围栏+补播>围栏+施肥>围栏>不围栏。围栏+补播对土壤的改善效果明显优于其他3种措施,是玛曲高寒草甸生态恢复的重要途径。

Effects of different management measures on soil microbial biomass in an alpine meadow

In this study, soil microbial biomass characteristics were monitored during 2011-2014 in Maqu alpine meadows under four different management strategies: non-fenced, enclosed, enclosed with fertilization, and enclosed and sowing. Soil microbial biomass carbon (SMBC), soil microbial biomass nitrogen (SMBN), and soil microbial biomass phosphorus (SMBP) were analyzed using the chloroform fumigation extraction method. The results showed that in the same year, the different management measures were ranked, from highest soil microbial biomass in the 0-20 cm soil layer to lowest, as follows: enclosed+sowing>enclosed+fertilization>enclosed>non-fenced, and from highest soil microbial biomass in the 20-40 cm soil layer to lowest, as follows: enclosed+fertilization>enclosed+sowing>enclosed>non-fenced. In the same year, soil microbial biomass in the 0-20 cm soil layer was always greater (1.22 to 3.39 times greater) than that in the 20-40 cm soil layer. With the same management measure and soil depth (0-20 cm or 20-40 cm), soil microbial biomass increased from 2011 to 2012, peaking in 2012 and decreased again afterwards, except for SMBC in the 0-20 cm soil layer in the non-fenced treatment. With the same management measures, the annual variation in soil microbial biomass in the 0-20 cm soil layer was greater than that in the 20-40 cm soil layer. The soil microbial biomass was negatively correlated with temperature, and significantly positively correlated with precipitation. The management measures were ranked, from highest soil quality composite index to lowest, as follows: enclosed+sowing>enclosed+fertilization>enclosed>non-fenced. The results showed that enclosure+sowing is a better soil management measure than the other three strategies for soil restoration and improvement. Consequently, enclosure+sowing should be applied for ecological restoration of Maqu alpine meadows.