东祁连山高寒草地返青期不同草地型土壤氮的分布特征  

Distribution characteristics of soil nitrogen during the greening period of forage under different alpine grasslands in the eastern Qilian Mountain

作　　者：杨成德[1] 陈秀蓉[1] 龙瑞军[2] 满元荣[1] 张俊忠[1] 

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中-美草地畜牧业可持续发展研究中心,甘肃兰州730070 [2]兰州大学草地农业科技学院,甘肃兰州730020

出　　处：《草业学报》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

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

关 键 词：东祁连山 高寒草地 微生物量氮 分布 

分 类 号：S812.2[农业科学—草业科学] S155.47[农业科学—畜牧学]