不同管理措施对高寒草甸土壤微生物氮素生理群数量影响研究  

Effects of different management strategies on the number of soil nitrogen microorganism groups in an alpine meadow

作　　者：张建贵[1] 蒋永梅[1] 姚拓[1] 高亚敏[1] 李海云[1] 兰晓君[1] 田永亮[1] 李建宏[1] 张英[2] 

机构地区：[1]甘肃农业大学草业学院,草业生态系统教育部重点实验室,甘肃省草业工程实验室,中-美草地畜牧业可持续发展研究中心,甘肃兰州730070 [2]青海大学农牧学院,青海西宁810016

出　　处：《草业学报》2017年第8期65-73,共9页Acta Prataculturae Sinica

基　　金：国家自然科学基金资助项目(31360584);国家科技支撑技术(2009BAC53B06)资助

摘　　要：从微观视野认识土壤氮素形成机理,为高寒草甸微生物生长和恢复提供科学依据。本研究采用平板表面涂抹法和稀释法对玛曲高寒草甸4种不同管理措施(不围栏、围栏、围栏+施肥、围栏+补播)土壤微生物氮素生理群数量进行了测定分析,结果表明,1)同一管理措施下,不同空间层次土壤微生物氮素生理群数量变化较大,具有明显的垂直分布规律,0~10cm和10~20cm土层的数量均显著高于20~30cm土层(P<0.05),一般前者是后者的1.23~4.03倍和1.11~2.25倍;且不同土壤微生物氮素生理群之间数量差异显著,氨化细菌>反硝化细菌>硝化细菌>好气性固氮菌>嫌气性固氮菌。2)同一空间层次,不同管理措施土壤微生物氮素生理群间数量差异较大。土壤微生物氮素生理群数量以围栏+施肥和围栏+补播草地最高,围栏草地次之,不围栏草地最少。3)不同管理措施,土壤铵态氮和硝态氮含量随着土层深度增加逐渐减少,但围栏+施肥和围栏+补播处理均显著高于其他处理(P<0.05)。可见,围栏+施肥和围栏+补播措施对玛曲高寒草甸土壤微生物氮素生理群数量和不同形态氮素含量有提高效果。Understanding the micro-mechanisms of soil nitrogen formation can provide useful information about the growth and recovery of microorganisms in an alpine meadow. In this study, soil samples were collected from the alpine meadow in Maqu from sites under four types of management; unfenced, enclosed, enclosed with fertilization, and enclosed with sowing. The number of soil nitrogen microorganism groups was deter-mined by the plate colony count and MPN （most probable number） methods. The number of nitrogen bacterial ＊ ＊groups decreased with increasing soil depth at all sites. The number of nitrogen bacterial groups was signifi-cantly higher in the 0 - 10 cm and the 10 - 2 0 cm soil layers （P 〈0.05） than in the 20 - 30 cm soil layer （1. 23 -4. 03 times and 1. 11 -2. 25 times that in the 20 -30 cm soil layer, respectively）. There were also sig-nificant differences in abundance among the microorganism groups. The groups were ranked, from most abun-dant to least abundant, as follows： ammonifiers^denitrifying bacteria〉nitrifiers〉aerobic nitrogen-fixing bac-teria （aerobic NFB）〉anaerobic nitrogen-fixing bacteria （anaerobic NFB）. In the same soil layer, there were significant differences in the abundance of bacterial groups among the different management strategies. The ni-trogen bacterial groups were most abundant in the enclosed fertilized grassland and enclosed sown grassland, less abundant in enclosed grassland, and least abundant in the unfenced grassland. The amounts of ammonium nitrogen and nitrate nitrogen decreased with increasing soil depth in all treatments, and were significantly high-er in enclosed fertilized grassland and enclosed sown grassland （P 〈0. 0 5 ） than in enclosed grassland and un-fenced grassland. These results show that, in the alpine meadow, the number and types of soil microorganisms and the contents of different forms of nitrogen can be increased by enclosure with sowing and enclosure withfertilization.

关 键 词：高寒草甸 土壤微生物 氮素生理群 管理措施 

分 类 号：S812.2[农业科学—草业科学]