不同管理措施对高寒草甸土壤微生物量季节性变化的影响

采用氯仿熏蒸浸提法测定了4种不同管理措施(不围栏、围栏、围栏+施肥、围栏+补播)土壤微生物量碳、氮和磷季节变化,结果表明:(1)相同月份,相同土层,不同管理措施,土壤微生物量表现为:围栏+补播围栏+施肥围栏不围栏;(2)相同月份,不同土层,相同管理措施,土壤微生物量表现为:0~20cm20~40cm,且前者为后者的1.16~3.13倍;(3)不同月份,相同土层,相同管理措施,土壤微生物量的季节变化均呈先增后降的趋势,7月出现最大值,各月间呈不同的显著性差异;(4)不同月份,不同土层,相同管理措施,0~20cm土层土壤微生物量季节变化幅度高于20~40cm。土壤微生物量季节变化与气温变化呈极显著正相关(P0.01),与降水量呈正相关。运用综合指数法计算不同管理措施下土壤质量综合指数,其排序为:围栏+补播(0.193)围栏+施肥(0.096)围栏(-0.059)不围栏(-0.231)。围栏+补播对土壤的改善效果最佳,是玛曲高寒草甸生态恢复的重要途径。

Effect of different management patterns on seasonal dynamics of soil microbial biomass in the alpine meadow

Seasonal dynamics of soil microbial biomass carbon (SMBC),soil microbial biomass nitrogen (SMBN)and soil microbial biomass phosphorus(SMBP)were tested and analyzed with the chloroform fumiga-tion extraction method in alpine meadow in Maqu under different management measures.The main results ob-tained as follows:1)in the same month and soil depth,soil microbial biomass shown a decreasing tendency(en-closure + reseeding > enclosure + fertilization > enclosure > no-fence);2)in same month and management measures,soil microbial biomass with different soil depth(0 to 20 cm or 20 to 40 cm)shown a decreasing tend-ency(0 to 20 cm > 20 to 40 cm),they were much greater(1.1 6 to 3.13 times)in 0 to 20 cm soil depth than that in 20 to 40 cm;3)in same management measures and soil depth(0 to 20 cm or 20 to 40 cm),the seasonal trend of soil microbial biomass reached the peak in July and then declined,the differences among months were signifi-cant;4)in same management measures,the seasonal dynamics of soil microbial biomass with the different month and soil depth(0 to 20 cm or 20 to 40 cm)shown a decreasing tendency(0 to 20 cm > 20 to 40 cm).Soil micro-bial biomass was significantly related with temperature(P <0.010),and positively correlated with precipitation. The synthetic index method was used to calculate a soil quality index under different management patterns,the tendency of the values of the soil quality indices was as follows:enclosure + reseeding(0.1 93)> enclosure +fertilization(0.096)> enclosure(-0.059)> no-fence(-0.231).It could be concluded that the enclosure +reseeding was the best for the ecological restoration of alpine meadow.