Distribution characteristics of soil organic carbon and nitrogen in farmland and adjacent natural grassland in Tibet

Liu Heman, Cao Lihua, Xu Changchang, Yang Hong, Li Baoguo

Abstract


Land-use significantly affects soil organic carbon (SOC) and nitrogen cycling, eventually leading to global climate change. The cold and arid climate conditions in Tibet are not conducive to transformation of SOC and nitrogen. Hence, research on SOC and nitrogen distribution under different land-use patterns in Tibet is an important basis to assess the soil carbon and nitrogen potential in the land ecosystem of this area. This study aims to explain the effects of two land-use patterns, namely, farmland and grassland, on SOC and nitrogen contents in the cold regions of Tibet. This study also seeks to provide a scientific basis for the agricultural and grass production system. To achieve these goals, the changing features of total nitrogen (TN), mineralized nitrogen (nitrate nitrogen (NN) and ammonium nitrogen (AN)), and SOC were analyzed in different soil depths (0-5, 5-10, 10-20, 20-30, 30-40, and 40-50 cm) in farmland and adjacent natural grassland. The differences in carbon and nitrogen contents between the farmland and grassland of the main agricultural area of Tibet were determined through combined field survey and lab analysis. Results showed that the contents of SOC, TN and mineralized nitrogen in the grassland and farmland decreased with increasing soil depth mainly in the surface with depth of 0-20 cm. The effects of the different land-use patterns on the contents of SOC and TN were primarily evident in the 0-10 cm surface layer. The contents of SOC and TN in the farmland were significantly lower than those in the grassland, with mean reduction by 28.36% for SOC and 20.76% for TN. When the soil layer is deeper than 10 cm, the contents of SOC and TN in the farmland were greater than those in the grassland. This finding indicated that the transformation from grassland to farmland in Tibet mainly influenced the SOC and TN in the 0-10 cm surface layer. Moreover, the results showed that the increment of carbon in the deep soil layers of the farmland partially offsets the SOC loss from the surface because of cultivation. The ratio of mineralized nitrogen to TN in the farmland was significantly higher than that in the grassland (p<0.001). Mineralized nitrogen in the farmland mainly existed in the form of NN, with a mean content of 2.7% in the 0-50 cm surface layer. By contrast, the difference in the ratio of AN to TN between the grassland and farmland was not significant. The results revealed that the land-use pattern in extremely cold agricultural areas mainly affects the contents of SOC and nitrogen in the 0-10 cm surface layer, and agricultural management is beneficial in increasing the SOC content in the deeper layers.
Keywords: Tibet, farmland, grassland, soil organic carbon, soil total nitrogen, nitrate nitrogen, ammonium nitrogen
DOI: 10.3965/j.ijabe.20160901.2220

Citation: Liu H M, Cao L H, Xu C C, Yang H, Li B G. Distribution characteristics of soil organic carbon and nitrogen in farmland and adjacent natural grassland in Tibet. Int J Agric & Biol Eng, 2016; 9(1): 135－145.

Keywords


Tibet, farmland, grassland, soil organic carbon, soil total nitrogen, nitrate nitrogen, ammonium nitrogen

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References


Poeplau C, Don A, Vesterdal L, Leifeld J, Van Wesemael B A S, Schumacher J, et al. Temporal dynamics of soil organic carbon after land‐use change in the temperate zone–carbon response functions as a model approach. Global Change Biology, 2011; 17(7): 2415−2427.

Cao L H, Liu H M, Zhao S W. Relationship between carbon and nitrogen in degraded alpine meadow soil. African Journal of Agricultural Research, 2012; 7: 3945−3951.

Puget P, Lal R. Soil organic carbon and nitrogen in a Mollisol in central Ohio as affected by tillage and land use. Soil and Tillage Research, 2005; 80(1): 201−213.

Fu X L, Shao M A, Wei X R, Robertm H. Soil organic carbon and total nitrogen as affected by vegetation types in Northern Loess Plateau of China. Geoderma, 2010; 155: 31−35.

Cheng X L, Yang Y H, Li M, Dou X L, Zhang Q F. The impact of agricultural land use changes on soil organic carbon dynamics in the Danjiangkou Reservoir area of China. Plant and soil, 2013; 366(1-2): 415−424.

Albaladejo J, Ortiz R, Garcia-Franco N, Navarro A R, Almagro M, Pintado J G, et al. Land use and climate change impacts on soil organic carbon stocks in semi-arid Spain. Journal of Soils and Sediments, 2013; 13(2): 265−277.

Eglin T, Ciais P, Piao S L, Barré P, Belassen V, Patricia C, et al. Overview on response of global soil carbon pools to climate and landuse changes. Sustaining Soil Productivity in Response to Global Climate Change: Science, Policy, and Ethics, 2011; 7: 183−199.

Don A, Schumacher J, Freibauer A. Impact of tropical land-use change on soil organic carbon stocks–a meta-analysis. Global Change Biology, 2011; 17(4): 1658−1670.

Wu H B, Guo Z T, Peng C H. Land use induced changes of organic carbon storage in soils of China. Global Change Biology, 2003; 9(3): 305−315.

Schrumpf M, Kaiser K, Guggenberger G, Persson T, Kögel-Knabner I, Schulze E D. Storage and stability of organic carbon in soils as related to depth, occlusion within aggregates, and attachment to minerals. Biogeosciences, 2013; 10: 1675−1691.

Lorenz K, Lal R. The depth distribution of soil organic carbon in relation to land use and management and the potential of carbon sequestration in subsoil horizons. Advances in agronomy, 2005; 88: 35−66.

Poeplau C, Don A. Sensitivity of soil organic carbon stocks and fractions to different land-use changes across Europe. Geoderma, 2013; 192: 189−201.

Wang G X, Ju Q, Cheng G D, Lai Y M. Soil organic carbon pool of grassland soils on the Qinghai-Tibetan Plateau and its global implication. Science of the Total Environment, 2002; 291(1): 207−217.

Wang X D, Zhong X H, Liu S Z, Liu J G, Wang Z Y, Li M H. Regional assessment of environmental vulnerability in the Tibetan Plateau: Development and application of a new method. Journal of Arid environments, 2008; 72(10): 1929−1939.

Cui X F, Graf H F. Recent land cover changes on the Tibetan Plateau: a review. Climatic Change, 2009; 94(1-2): 47−61.

Yang C Y, Shen W S, Wang T. Spatial-temporal characteristics of cultivated land in Tibet in recent 30 years. Transactions of the CSAE, 2015; 31(1): 264−271. (in Chinese with English abstract)

Yang Y H, Fang J Y, Smith P, Tang Y H, Chen A P, Ji C J, et al. Changes in topsoil carbon stock in the Tibetan grasslands between the 1980s and 2004. Global Change Biology, 2009; 15(11): 2723−2729.

Paltridge N, Tao J, Unkovich M, Bonamano A, Gason A, Grover S, et al. Agriculture in central Tibet: an assessment of climate, farming systems, and strategies to boost production. Crop and Pasture Science, 2009; 60(7): 627−639.

Zhong G H, Tian F Y, Wang M, Zhang H F, Liu C H, Ci B. Soil fertility of croplands in major agricultural areas in Tibet. Acta Pedologica Sinica, 2005; 42(6): 1030−1034. (in Chinese with English abstract)

Tao H P, Gao P, Zhong X H. A study of regional eco-environment vulnerability—A case of “One-River- Two-Tributaries”, Tibet. Journal of Mountain Science, 2006; 24(6): 761−768. (in Chinese with English abstract)

Bao S D. Soil agricultural chemistry analysis. Beijing: China agriculture press, 1999. (in Chinese)

Grünzweig J M, Sparrow S D, Chapin F S. Impact of forest conversion to agriculture on carbon and nitrogen mineralization in subarctic Alaska. Biogeochemistry, 2003; 64(2): 271−296.

Schütt M, Borken W, Spott O, Stange C F, Matzner E. Temperature sensitivity of C and N mineralization in temperate forest soils at low temperatures. Soil Biology and Biochemistry, 2014; 69: 320−327.

Cassman K G, Munns D N. Nitrogen mineralization as affected by soil moisture, temperature, and depth. Soil Science Society of America Journal, 1980; 44(6): 1233−1237.

Stenger R, Priesack E, Beese F. Rates of net nitrogen mineralization in disturbed and undisturbed soils. Plant and Soil, 1995; 171(2): 323−332.

Glendining M J, Powlson D S, Poulton P R, Bradbury N J, Palazzo D, Li X. The effects of long-term applications of inorganic nitrogen fertilizer on soil nitrogen in the Broadbalk Wheat Experiment. The Journal of Agricultural Science, 1996; 127(03): 347−363.

Chen F S, Zeng D H, Narain S A, Chen G S. Effects of soil moisture and soil depth on nitrogen mineralization process under Mongolian pine plantations in Zhanggutai sandy land, PR China. Journal of Forestry Research, 2005; 16(2): 101−104.

Di H J, Cameron K C, Shen J P, Winefield C S, O'Callaghan M, Bowatte S, He J Z. Ammonia-oxidizing bacteria and archaea grow under contrasting soil nitrogen conditions. FEMS Microbiology Ecology, 2010; 72(3): 386−394.

Jobbágy E G, Jackson R B. The vertical distribution of soil organic carbon and its relation to climate and vegetation. Ecological applications, 2000; 10(2): 423−436.

Tao Z, Shen C D, Gao Q Z, Sun Y M, Yi W X, Li Y N. Soil organic carbon storage and vertical distribution of alpine meadow on the Tibetan Plateau. Acta Geographica Sinica, 2006; 61(7): 720−728. (in Chinese with English abstract)

Shi P L, Yu G R. Soil carbon stock patterns of different land use types in the lower Lhasa river. Resources Science, 2003; 25(5): 96−102. (in Chinese with English abstract)

Schmidt M W I, Torn M S, Abiven S, Dittmar T, Guggenberger G, Janssens I A, et al. Persistence of soil organic matter as an ecosystem property. Nature, 2011; 478(7367): 49−56.

Kätterer T, Bolinder M A, Andrén O, Kirchmann H, Menichetti L. Roots contribute more to refractory soil organic matter than aboveground crop residues, as revealed by a long-term field experiment. Agriculture Ecosystems and Environment, 2011; 141(1-2): 184−192.

Yang Y H, Fang J Y, Ji C J, Han W X. Above‐and belowground biomass allocation in Tibetan grasslands. Journal of Vegetation Science, 2009; 20(1): 177−184.

Fan Y, Liu S Q, Zhang S R, Deng L J. Background organic carbon storage of topsoil and whole profile of soils from Tibet district and their spatial distribution. Acta Ecologica Sinica, 2006; 26(9): 2834−2946. (in Chinese with English abstract)

Liu W J, Chen S Y, Qin X, Baumann F, Scholten T, Zhou Z Y, et al. Storage, patterns, and control of soil organic carbon and nitrogen in the northeastern margin of the Qinghai–Tibetan Plateau. Environmental Research Letters, 2012; 7(3): 1−12.

Yang Y H, Fang J Y, Guo D L, Ji C J, Ma W H. Vertical patterns of soil carbon, nitrogen and carbon: nitrogen stoichiometry in Tibetan grasslands. Biogeosciences Discussions, 2010; 7(1): 1−24.

Klemedtsson L, Von Arnold K, Weslien P, Gundersen P. Soil C N ratio as a scalar parameter to predict nitrous oxide emissions. Global Change Biology, 2005; 11(7): 1142− 1147.

Wang J L, Zhong Z M, Wang Z H, Chen B X, Yu C Q, Hu X X, et al. Soil C/N distribution characteristics of alpine steppe ecosystem in Qinhai-Tibetan Plateau. Acta Ecologica Sinica, 2014; 34(22): 6678−6691. (in Chinese with English abstract)

Tian H Q, Chen G S, Zhang C, Melillo J M, Hall C A S. Pattern and variation of C:N:P ratios in China’s soils: a synthesis of observational data. Biogeochemistry, 2010, 98(1-3): 139−151.

Ohtsuka T, Hirota M, Zhang X Z, Shimono A, Senga Y, Du M G, et al. Soil organic carbon pools in alpine to nival zones along an altitudinal gradient (4400–5300 m) on the Tibetan Plateau. Polar Science, 2008; 2(4): 277−285.

Bai J H, Ouyang H, Xiao R, Gao J Q, Gao H F, Cui B S, et al. Spatial variability of soil carbon, nitrogen, and phosphorus content and storage in an alpine wetland in the Qinghai–Tibet Plateau, China. Soil Research, 2010; 48(8): 730−736.




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