摘要
本试验在东祁连山选择代表性的７种高寒草地型为研究对象，在返青期对其土壤微生物量氮、全氮、Ｋ２ＳＯ４浸提氮、碱解氮、氮密度及其相关性进行了研究。结果表明，土壤全氮、碱解氮和氮密度分别介于４．２～７．９ｇ／ｋｇ、１０４．１～２３４．０ｍｇ／ｋｇ和０．３８～０．６１ｋｇ／ｍ２。２００５ 和２００６ 年土壤Ｋ２ＳＯ４浸提氮分别介于３．４～１１．４ 和１．８～１３．９ｍｇ／ｋｇ，占土壤微生物量氮的３．９３％～１１．６２％和３．８８％～１５．３７％。微生物量氮在２００５和２００６年分别介于４９．０～１４３．０ｍｇ／ｋｇ和３５．９～１７１．７ｍｇ／ｋｇ；与Ｋ２ＳＯ４浸提碳在灌丛草地呈显著正相关（P＜０．０５），在草本草地呈极显著正相关（P＜０．０１）；与Ｋ２ＳＯ４ 浸提氮在杜鹃灌丛和高山柳灌丛呈极显著正相关（P＜０．０１），在金露梅灌丛和草本草地呈显著正相关（P＜０．０５）。除嵩草草地外，微生物量氮与微生物量碳和微生物量磷呈极显著正相关（P＜０．０１）。２００５年Ｋ２ＳＯ４浸提氮和微生物量氮对土壤全氮贡献率分别为０．０７％ ～０．１６％ 和１．１６％ ～１．９３％。在东祁连山高寒草地，草地型间土壤全氮、碱解氮、Ｋ２ＳＯ４ 浸提氮及微生物量氮有明显差异，且草地型决定了微生物量氮的数量和生态分布，植物群落是影响微生物量氮数量和生态分布及其与土壤Ｋ２ＳＯ４浸提碳、氮相关性的关键因素之一；微生物量碳、氮、磷间的相关性由土壤微生物本身或其群落结构决定。
Seven different alpine grassland types [Rhododendrons brushland （DJ）, Salix cupularis brushland （GL）, Potentilla fruticosa brushland （JL）, Polygomem viviparum grassland （ZY）, Grass steppe （HC）, Swamp grassland （ZZ） and Kobresia grassland （SC）] in the eastern Qilian Mountains of the Qinghai--Tibetan Plateau, west China, were investigated for their soil nitrogen [Including microbial biomass nitrogen （MBN）, soil total nitrogen, K2SO4-extractable nitrogen, alkali-hydrolysable nitrogen and nitrogen density] and their co-relationships. Soil total nitrogen, alkali-hydrolysable nitrogen, and nitrogen density varied from 4.2 to 7. 9 g/kg, 104.1 to 234. 0 mg/kg, and 0. 38 to 0. 61 kg/me, respectively. In 2005 and 2006, K2SO4 extractable nitrogen ranged from 3.4 to 11.4 mg/kg and 1.8 to 13.9 mg/kg, respectively. The contribution of K2SO4-extractable nitrogen to MBN varied from 3.93% to 11.62% in 200S and 3.88% to 15.37% in 2006. MBN ranged from 49.0 to 143.0 mg/kg in 2005 and 35.9 to 171.7 mg/kg in 2006. MBN showed a significant positive correlation at P〈0.05 with K2SO4-extractable carbon under brushland and a significant positive correlation at P〈0. 01 with K2SO4-extractable carbon under grassland. It also showed a significant positive correlation at P〈0.01 with K2SO4-extractable nitrogen under DJ and GL, and a significant positive correlation at P〈0.05 with K2SO4-extractable nitrogen under JL, ZY, HC, ZZ and SC. With the exception of SC, MBN showed a significant positive correlation at P〈0. 01 with MBC or MBP. The contribution of K2SO4-extraetable nitrogen or MBN to soil total nitrogen varied from 0.07% to 0. 16% and 1. 16% to 1.9% respectively in 2005. In the eastern Qilian Mountains of the Qinghai -- Tibetan Plateau, the values of total nitrogen, K2SO4-extractable nitrogen, and alkali-hydrolysable nitrogen were differed between the different types of grassland. Furthermore, the type of grassland was the deciding factor for quantity and ecological distribution of soil MBN and plant communities, and was the important factor influencing their quantity and ecological distribution, and the co-relationship between MBN and K2SO4-extractable nitrogen or K2SO4-extractable carbon. The co-relationship between MBN and MBC or MBP was decided by soil microorganism communities or their community structure.
出处
《草业学报》
CSCD
北大核心
2010年第1期67-74,共8页
Acta Prataculturae Sinica
基金
甘肃省自然科学基金(096RJZA003)
退化草原植被恢复与碳固定之间的研究(052456CHA-GS-Y-4)资助
关键词
东祁连山
高寒草地
微生物量氮
分布
eastern Qilian Mountain
alpine grassland
microbial biomass nitrogen
distribution
