东祁连山高寒草地返青期不同草地型土壤氮的分布特征

摘要/Abstract

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4.2~7.9 g/kg、104.1~234.0 mg/kg和0.38~0.61 kg/m²。2005和2006年土壤K₂SO₄浸提氮分别介于3.4~11.4和1.8~13.9 mg/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49.0~143.0 mg/kg和35.9~171.7 mg/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。

Abstract: Seven different alpine grassland types [Rhododendrons brushland (DJ), Salix cupularis brushland (GL), Potentilla fruticosa brushland (JL), Polygonum 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/m², 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 2005 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-extractable nitrogen or MBN to soil total nitrogen varied from 0.07% to 0.16% and 1.16% to 1.93% 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.

中图分类号:

杨成德,陈秀蓉,龙瑞军^2*,满元荣,张俊忠. 东祁连山高寒草地返青期不同草地型土壤氮的分布特征[J]. 草业学报, 2010, 19(1): 67-74.

YANG Cheng-de, CHEN Xiu-rong, LONG Rui-jun, MAN Yuan-rong, ZHANG Jun-zhong. Distribution characteristics of soil nitrogen during the greening period of forageunder different alpine grasslands in the eastern Qilian Mountain[J]. Acta Prataculturae Sinica, 2010, 19(1): 67-74.

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