施氮对高寒草甸草原植物群落和土壤养分的影响

doi:10.7522/j.issn.1000-694X.2015.00043

摘要/Abstract

摘要： 于2013-2014年在青藏高原东缘测定了不同梯度施氮后植物群落特征、牧草营养和土壤质量的变化,并分析了施氮后的经济效益。结果表明:(1)施氮显著增加了各功能群植物的高度和禾本科功能群植物盖度,而对莎草科和豆科植物盖度无显著影响;施氮显著增加了禾本科、莎草科、豆科和植物群落生物量,降低了杂类草盖度和生物量,其中施肥量为30.86～38.58 g·m^-2时效果最为显著。(2)施氮显著增加了0～20 cm土层根系生物量;施氮当年显著增加了根冠比,施氮第2年根冠比无显著变化。(3)施氮不同程度降低了高寒草甸草原植物群落多样性,其中,施肥量在30.86～38.58 g·m^-2时最低。(4)施氮不同程度地提高了禾本科、莎草科和杂类草植物的粗蛋白含量,降低了各功能群植物纤维含量;施氮不同程度提高了高寒草甸草原土壤养分和有机碳含量,其中在施肥量为30.86～38.58 g·m^-2时最高。(5)施氮当年和第二年净收益均在施肥量为30.86 g·m^-2时最大,分别为1 860元·hm^-2和878元·hm^-2。施氮缓解了青藏高原东缘高寒草甸草原植物生长的营养限制,提高了可食牧草产量,30.86～38.58 g·m^-2可作为该区最佳施氮水平。

关键词: 高寒草甸草原, 施氮梯度, 群落特征, 土壤养分

Abstract: A two-year field trials (2013-2014) was conducted in the eastern Tibetan Plateau to address the responses of plant community characteristics and soil nutrient to varying fertilizer gradients (0, 7.72, 11.57, 19.29, 27, 30.86, 38.58 and 46.3 g·m^-2). The fertilizer application significantly increased the Gramineous coverage and aboveground biomass of Cyperaceae and Leguminosae plants; while the forbs function group coverage and biomass decreased obviously, and there was no significant effect on the coverage of Cyperaceae and Leguminosae plant function group, among which the most significant effects appeared when fertilizer application is 30.86-38.58 g·m^-2 N fertilizer level. N fertilizer application significantly increased root biomass in the 0-20 cm soil layer, and also increased the ratio of root to shoot in the first year, but no significant difference in the second year. N application significantly decreased the plant species diversity index, especially obvious at 30.86-38.58 g·m^-2. Nitrogen application reduced forage fiber, improved crude protein content of the Gramineae, Cyperaceae and forbs plants. Soil total nutrients and available nutrients were increased inordinately when fertilizer application, and were higher at 30.86 g·m^-2or 38.58 g·m^-2N fertilizer. Net income showed a unimodal curve with various fertilizer gradients rise with a maximum of 30.86 g·m^-2. N fertilizer have improved the alpine meadow-steppe soil nutrient status and stimulate plant growth, between 30.86-38.58 g·m^-2 N fertilizer application can be the optimal level.

Key words: alpine meadow-steppe, N fertilizer, plant community characteristics, soil nutrient

中图分类号:

Q948.1

曹文侠, 李文, 李小龙, 徐长林, 师尚礼, 韩天虎. 施氮对高寒草甸草原植物群落和土壤养分的影响[J]. 中国沙漠, 2015, 35(3): 658-666.

Cao Wenxia, Li Wen, Li Xiaolong, Xu Changlin, Shi Shangli, Han Tianhu. Effects of Nitrogen Fertilization on Plant Community Structure and Soil Nutrient in Alpine Meadow-steppe[J]. JOURNAL OF DESERT RESEARCH, 2015, 35(3): 658-666.

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