青藏高原退化高寒草地土壤氮矿化特征以及影响因素研究

doi:10.11686/cyxb2017291

摘要/Abstract

摘要： 为了明确青藏高原退化高寒草地土壤氮矿化特点以及影响因素,以高寒草甸和高寒草原为研究对象,运用原位培养法对健康与退化条件下2类型草地中土壤硝化速率、氨化速率以及氮素转化微生物、植物和土壤等因子进行了研究。结果表明:1)草地退化显著降低了高寒草甸和草原土壤净硝化速率和净氨化速率;2)草地退化降低了2类高寒草地土壤硝化细菌和氨化细菌数量,降低了土壤蛋白酶、脲酶活性;3)草地退化显著降低了NH₄-N和NO₃-N含量,降低了微生物生物量氮含量。相关分析表明,高寒草地中土壤硝化速率和氨化速率与土壤硝化细菌和氨化细菌的数量以及蛋白酶和脲酶密切相关。植物生物量、土壤含水量、有机碳、全氮含量通过影响微生物数量、微生物生物量及酶活性而成为影响土壤氮素转化的主要因素。因此,草地退化通过降低高寒草地硝化细菌和氨化细菌、土壤酶活性而降低土壤氮素转化速率和土壤有效氮的供给。

关键词: 草地退化, 硝化速率, 氨化速率, 氮素转化微生物, 高寒草地

Abstract: Alpine meadow and alpine steppe were studied to explore the mechanisms of degradation in soil nitrogen transformation and the key factors that affect soil N transformation in grasslands of the Qinghai Tibet Plateau. The net nitrification rate and net ammonification rate, as well as the microbial aspects of nitrogen transformation, plant and soil factors, were investigated using the method of in situ incubation. The results showed that: 1) The net nitrification and ammonification rates were significantly reduced by degradation in alpine grassland ecosystems; 2) The number of nitrifiers and ammonifiers in the soil, soil urease and protease activities decreased in the degraded meadows and steppe. 3) NH₄-N and NO₃-N contents were significantly reduced and microbial biomass nitrogen (MBN) also decreased. Soil nitrification and ammonification rates were closely related to the number of ammonifiers and nitrifiers, microbial biomass, and the extent of protease and urease in soils. Plant biomass, soil water, organic carbon and total nitrogen content were the main factors affecting soil N transformation by influencing the number of microbes, microbial biomass and enzyme activities. In conclusion, soil N transformation rates and the supply of available nitrogen in soils declined in degraded alpine grassland due to reductions in nitrogen transformation microbes and soil enzyme activities.

Key words: grassland degradation, nitrification rate, ammonification rate, nitrogen transformation microbes, alpine grassland

王学霞, 董世魁, 高清竹, 张勇, 胡国铮, 罗文蓉. 青藏高原退化高寒草地土壤氮矿化特征以及影响因素研究[J]. 草业学报, 2018, 27(6): 1-9.

WANG Xue-xia, DONG Shi-kui, GAO Qing-zhu, ZHANG Yong, HU Guo-zheng, LUO Wen-rong. The rate of soil nitrogen transformation decreased by the degradation of alpine grasslands in the Qinghai Tibet Plateau[J]. Acta Prataculturae Sinica, 2018, 27(6): 1-9.

参考文献

[1] Saugier B, Roy J, Mooney H A.Estimations of global terrestrial productivity: converging toward a single number. Terrestrial Global Productivity, 2001: 543-557.
[2] Piao S L, Fang J Y, He J S, et al. Spatial distribution of grassland biomass in China. Acta Phytoecologica Sinica, 2004, 28(4): 491-498.
朴世龙, 方精云, 贺金生, 等. 中国草地植被生物量及其空间分布格局. 植物生态学报, 2004, 28(4): 491-498.
[3] Xia J, Liu S, Liang S, et al. Spatio-temporal patterns and climate variables controlling of biomass carbon stock of global grassland ecosystems from 1982 to 2006. Remote Sensing, 2014, 6(3): 1783-1802.
[4] Han J G, Zhang Y J, Wang C J, et al. Rangeland degradation and restoration management in China. Rangeland Journal, 2008, 30(2): 233-239.
[5] LeBauer D S, Treseder K K. Nitrogen limitation of net primary productivity in terrestrial ecosystems is globally distributed. Ecology, 2008, 89(2): 371-379.
[6] Fornara D A, Tilman D, Hobbie S E.Linkages between plant functional composition, fine root processes and potential soil N mineralization rates. Journal of Ecology, 2009, 97: 48-56.
[7] Cregger M A, McDowell N G, Pangle R E, et al. The impact of precipitation change on nitrogen cycling in a semi-arid ecosystem. Functional Ecology, 2014, 28(6): 1534-1544.
[8] Philippot L, Spor A, Hénault C, et al. Loss in microbial diversity affects nitrogen cycling in soil. The International Society for Microbial Ecology Journal, 2013, 7(8): 1609-1619.
[9] Tian X F, Hu H W, Ding Q, et al. Influence of nitrogen fertilization on soil ammonia oxidizer and denitrifier abundance, microbial biomass, and enzyme activities in an alpine meadow. Biology and Fertility of Soils, 2014, 50(4): 703-713.
[10] Kaštovská E, Šantrūĉková H.Comparison of uptake of different N forms by soil microorganisms and two wet grassland plants: a pot study. Soil Biology and Biochemistry, 2011, 43(6): 1285-1291.
[11] Booth M S, Stark J M, Rastetter E.Controls on nitrogen cycling in terrestrial ecosystems: a synthetic analysis of literature data. Ecological Monographs, 2005, 75(2): 139-157.
[12] Zhou H S, Yang G W, Liu N, et al. Plant community and soil microbial characteristics in typical grasslands of different degradation degrees. Pratacultural Science, 2014, 31(1): 30-38.
周翰舒, 杨高文, 刘楠, 等. 不同退化程度的草地植被和土壤特征. 草业科学, 2014, 31(1): 30-38.
[13] Li J H, Li X P, Lu H, et al. Characteristics of, and the correlation between, vegetation and N fixing soil bacteria in alpine grassland showing various degrees of degradation. Acta Ecologica Sinica, 2017, 37(11): 3647-3654.
李建宏, 李雪萍, 卢虎, 等. 高寒地区不同退化草地植被特性和土壤固氮菌群特性及其相关性. 生态学报, 2017, 37(11): 3647-3654.
[14] Wen L, Dong S K, Li Y Y, et al. The impact of land degradation on the C pools in alpine grasslands of the Qinghai-Tibet Plateau. Plant and Soil, 2013, 368(1/2): 329-340.
[15] Bai Y X, Li X B, Wang H, et al. Nitrogen storage variations in typical steppe during grassland degradation progress-a case study of typical steppe in Xilin Hot City, Inner Mongolia. Pratacuhural Science, 2015, 32(3): 311-321.
[16] Gao Q Z, Wan Y F, Xu H M.Alpine grassland degradation index and its response to recent climate variability in Northern Tibet, China. Quaternary International, 2010, 226(1): 143-150.
[17] Liu J Y, Xu X L, Shao Q Q.Grassland degradation in the “Three-River Headwaters” region, Qinghai Province. Journal of Geographical Sciences, 2008, 18(3): 259-273.
[18] Cao X J, Ganjujav H, Gao Q Z, et al. Temporal and spatial distribution of grassland and degradation in northern Tibet based on NDVI. Acta Prataculturae Sinica, 2016, 25(3): 1-8.
曹旭娟, 干珠扎布, 高清竹, 等. 基于NDVI的藏北地区草地退化时空特征分析. 草业学报, 2016, 25(3): 1-8.
[19] Lu H, Yao T, Li J H, et al. Vegetation and soil microorganism characteristics of degraded grasslands. Acta Prataculturae Sinica, 2015, 24(5): 34-43.
卢虎, 姚拓, 李建宏, 等. 高寒地区不同退化草地植被和土壤微生物特性及其相关性研究. 草业学报, 2015, 24(5): 34-43.
[20] Chen L L, Shi J J, Wang Y L, et al. Study on different degraded degrees grassland community structure characteristics of the alpine area. Acta Agrestia Sinica, 2016, 24(1): 211-215.
陈乐乐, 施建军, 王彦龙, 等. 高寒地区不同退化程度草地群落结构特征研究. 草地学报, 2016, 24(1): 211-215.
[21] Wang X X, Dong S K, Yang B, et al. The effects of grassland degradation on plant diversity, primary productivity, and soil fertility in the alpine region of Asia’s headwaters. Environmental Monitoring and Assessment, 2014, 186(10): 6903-6917.
[22] Dong S K, Wen L, Li Y Y, et al. Soil-quality effect of grassland degradation and restoration on the Qinghai-Tibetan Plateau. Soil Science Society of America Journal, 2012, 76(6): 2256-2264.
[23] He F P, Zeng W J, Wang Z D, et al. Effect of temperate grassland deterioration on soil microbiological characteristics at different depths. Microbiology, 2016, 43(3): 702-711.
贺凤鹏, 曾文静, 王曌迪, 等. 温带草原退化对土壤剖面微生物学特征的影响. 微生物学通报, 2016, 43(3): 702-711.
[24] Wen L, Dong S K, Zhu L, et al. The construction of grassland degradation index for alpine meadow in Qinghai-Tibetan Plateau. Procedia Environmental Sciences, 2010, 2: 1966-1969.
[25] Lin Q, Wu Y, Liu H.Modification of fumigation extraction method for measuring soil microbial biomass carbon. Chinese Journal of Ecology, 1999, 18: 63-66.
[26] Brookes P C, Landman A, Pruden G, et al. Chloroform fumigation and the release of soil nitrogen: a rapid direct extraction method to measure microbial biomass nitrogen in soil. Soil Biology and Biochemistry, 1985, 17(6): 837-842.
[27] Li Z G.Research methods of soil environmental microorganism. Beijing: Science Press, 2009.
李振高. 土壤与环境微生物研究法. 北京: 科学出版社, 2009.
[28] Burger M, Jackson L E.Microbial immobilization of ammonium and nitrate in relation to ammonification and nitrification rates in organic and conventional cropping systems. Soil Biology and Biochemistry, 2003, 35(1): 29-36.
[29] Jonasson S, Castro J, Michelsen A.Interactions between plants, litter and microbes in cycling of nitrogen and phosphorus in the arctic. Soil Biology and Biochemistry, 2006, 38(3): 526-532.
[30] Wu J G, Chang W, Ai L, et al. The soil nitrogen mineralization under four typical ecosystem in Qilian Mountains. Ecology and Environmnet, 2007, 16(3): 1000-1006.
吴建国, 苌伟, 艾丽, 等. 祁连山中部四种典型生态系统土壤氮矿化的研究. 生态环境, 2007, 16(3): 1000-1006.
[31] Zhang S, Chen D, Sun D, et al. Impacts of altitude and position on the rates of soil nitrogen mineralization and nitrification in alpine meadows on the eastern Qinghai-Tibetan Plateau, China. Biology and Fertility of Soils, 2012, 48(4): 393-400.
[32] Bengtson P, Bengtsson G.Bacterial immobilization and remineralization of N at different growth rates and N concentrations. The International Society for Microbial Ecology Ecology, 2005, 54(1): 13-19.
[33] Myrold D D, Posavatz N R.Potential importance of bacteria and fungi in nitrate assimilation in soil. Soil Biology and Biochemistry, 2007, 39(7): 1737-1743.
[34] Petersen D G, Blazewicz S J, Firestone M, et al. Abundance of microbial genes associated with nitrogen cycling as indices of biogeochemical process rates across a vegetation gradient in Alaska. Environmental Microbiology, 2012, 14: 993-1008.
[35] Liu T Z, Nan Z B.Advances in nitrification and nitrifying bacteria in grassland soil. Pratacultural Science, 2011, 28(6): 951-958.
刘天增, 南志标. 草地硝化微生物与硝化作用研究进展. 草业科学, 2011, 28(6): 951-958.
[36] Chu H Y, Paul G.Soil microbial biomass, nutrient availability and nitrogen mineralization potential among vegetation-types in a low arctic tundra landscape. Plant and Soil, 2010, 329(1): 411-420.
[37] Wang L D, Wang F L, Guo C X, et al. Progress of soil enzymology. Soils, 2016, 48(1): 1-10.
王理德, 王方琳, 郭春秀, 等. 土壤酶学研究进展. 土壤, 2016, 48(1): 1-10.
[38] Wang C, Long R, Wang Q, et al. Fertilization and litter effects on the functional group biomass, species diversity of plants, microbial biomass, and enzyme activity of two alpine meadow communities. Plant and Soil, 2010, 331(1/2): 377-389.
[39] Tian Y, Ouyang H, Gao Q, et al. Responses of soil nitrogen mineralization to temperature and moisture in alpine ecosystems on the Tibetan Plateau. Procedia Environmental Sciences, 2010, 2(6): 218-224.
[40] Leiros M C, Trasar-Cepeda C, Seoane S, et al. Dependence of mineralization of soil organic matter on temperature and moisture. Soil Biology and Biochemistry, 1999, 31: 327-335.
[41] Veresoglou S D, Sen R, Mamolos A P, et al. Plant species identity and arbuscular mycorrhizal status modulate potential nitrification rates in nitrogen-limited grassland soils. Journal of Ecology, 2011, 99(6): 1339-1349.
[42] Qin Y, He F, Tong Z Y, et al. Influence of fertilizer use on nitrogen transformation in soils of the Leymus chinensis steppe. Acta Prataculturae Sinica, 2016, 25(10): 48-55.
秦燕, 何峰, 仝宗永, 等. 施肥对羊草草原土壤氮素转化的影响. 草业学报, 2016, 25(10): 48-55.
[43] Oelmann Y, Buchmann N, Gleixner G, et al. Plant diversity effects on aboveground and belowground N pools in temperate grassland ecosystems: development in the first 5 years after establishment. Global Biogeochemical Cycles, 25(2): 415-421.
[44] Guntiñas M E, Leirós M C, Trasar-Cepeda C, et al. Effects of moisture and temperature on net soil nitrogen mineralization: a laboratory study. European Journal of Soil Biology, 2012, 48(1): 73-80.