Estimation of Carbon Sequestration in Iran Agroecosystems using Empirical Models

Document Type : Scientific - Research


1 Department of Agrotechnology, Faculty of Agriculture, Ferdowsi Uinversity of Mashhad, Mashhad, Iran

2 Department of Agroecology, Faculty of Agriculture, Ferdowsi Uinversity of Mashhad, Mashhad, Iran

3 Department of Agrotechnology, Faculty of Agriculture, Ferdowsi University of Mashhad, mashhad, Iran

4 Department of Soil Sciences, Faculty of Agriculture, Ferdowsi Uinversity of Mashhad, Mashhad, Iran


Carbon sequestration is defined as the permanent gain of carbon by soil, plant or water. Soil as the largest terrestrial carbon pool plays an important role in the global carbon cycle. Due to the role of agricultural systems in CO2 emission, attention to the carbon cycle in agricultural systems is of prime importance. So, the interest in agricultural soils and plant biomass as a carbon sink and an operational mechanism for reducing the atmospheric CO2 level, is increasing. It is estimated that world’s crop-based agriculture occupies 1.7 billion hectares, which can store up to 170 Pg carbon. Thus, the aims of this study were to simulate the relationship between crop residue decomposition rate with carbon to nitrogen ration (C:N) (an index of residue quality) as well as soil moisture regimes (the most important factors in residue decomposition) and also estimation of the attainable carbon sequestration in irrigated systems of five major crops in Iran based on the simulated model.
Materials and methods:
Residue decomposition rate of wheat, maize, rapeseed, cotton and soybean (with C:N ratios of 131, 69.7, 87.1, 57.8 and 95.9 , respectively)  in different soil moisture regimes (100, 60 and 30 percentage of field capacity) was studied in a 390-day incubation experiment. Study data was used for simulation of residue decomposition and relative decomposition rate was defined as a function of moisture (fm), C:N (fC:N) and temperature (ftemp). The simulated model was used to evaluate attainable carbon sequestration of the studied crops in five years from 2002-2003 to 2006-2007 based on yield, harvest index and shoot to root ratio in three scenarios of residue retention (100, 50 and 0 percentage of total residue produced) as well as three scenarios of soil moisture regimes of 100, 60 and 30 percentage of field capacity for different provinces of Iran. In this step, residue decomposition during one year after harvest was calculated using fm, fC:N and ft. The difference between proportions of the residue returned to the soil and decomposed residues were considered as un-decomposed residue which was multiplied by 0.45 to gain attainable carbon sequestration. Data of attainable carbon sequestration was analyzed as factorial experiment based on completely randomized design.
Results and discussion:
Results indicated that higher C:N and therefore lower residue quality caused lower residue decomposition rate. This parameter was also decreased in soils with lower moisture. Effects of soil moisture on reside decomposition was more pronounced than residue quality. comparison of attainable carbon sequestration in Iran’s provinces revealed that in wheat cropping systems: Kermanshah and Sistan and Balouchestan, in maize: Qazvin and Southern Khorasan, in rapeseed: Isfahan and Boushehr, in cotton: Eastern Azarbaijan and Hormozgan and in soybean cropping system: Ardebil and Eastern Azarbaijan provinces had the highest and lowest attainable carbon sequestration, respectively. Attainable carbon sequestration in all crops was decreased with increasing soil moisture from 30 to 60 and 100% of FC and decreasing residue retention from 100 to 50 and 0 % of total crop residue production. Maize and soybean showed the highest and lowest capability of carbon sequestration, respectively.
Results of the present study highlight the effects of environmental factors such as soil moisture as well as inherent properties of plant residues on residue decomposition. Climate and residue quality are the main determining factors of soil microorganisms activity and residue decomposition and therefore soil attainable carbon sequestration. Better soil moisture condition and temperature, also higher residue quality increases microorganisms activity resulting in more residue decomposition. Furthermore, plant biomass and residue management affects attainable carbon sequestration. Resultant of the mentioned factors determines attainable carbon sequestration in soils of agroecosystems. Regarding to the total carbon sequestration of afore-mentioned crops, Ardebil and Sistan and Balouchestan provinces showed the highest and lowest carbon sequestration, respectively.


Aerts, R. 1997. Climate, leaf litter chemistry and leaf litter decomposition in terrestrial ecosystems: a triangular relationship. Oikos 79: 439–449.
Belay-Tedla, A., Zhou, X., Su, B., Shiqiang Wan, S., and Luo, Y. 2009. Labile, recalcitrant, and microbial carbon and nitrogen pools of a tallgrass prairie soil in the US Great Plains subjected to experimental warming and clipping. Soil Biology and Biochemistry 41: 110–116.
Berg, B., Berg, M.P., Bottner, P., Box, E., Breymeyer, A., Calvan De Anta, R., Couteaux, M.M., Esudero, A., Gallardo, A., Kratz, W., Madeira, M., Malkonen, E., McClaugherty, C.A., Meentemeyer, V., Munoz, F., Piussi, P., Remacle, J., and Virzo de Santo, A. 1993. Litter mass loss in pine forests of Europe and Eastern United States as compared to actual evapotranspiration on a European scale. Biogeochemistry 20: 127–153.
Bolinder, M.A., Janzen, H.H., Gregorich, E.G., Angers, D.A., and VandenBygaart, A.J. 2007. An approach for estimating net primary productivity and annual carbon inputs to soil for common agricultural crops in Canada. Agriculture, Ecosystems and Environment 118: 29–42.
Bremner, J.M. 1970. Nitrogen total, regular kjeldahl method, In: Methods of Soil Analysis, Part 2: Chemical and Microbiological Properties. 2nd ed. Agronomy 9(1). A.S.A. Ins., S.S.S.A. Inc., Madison Publisher, Wisconsin., USA, pp. 610-616.
Bunnell, F.L., Tait, D.E.N., Flanagan, P.W., and Van Cleve, K. 1977. Microbial respiration and substrate weight loss. I. A general model of the influences of abiotic variables. Soil Biology and Biochemistry 9: 33–40.
Buyanovsky, G.A., and Wagner, G.H. 1986. Post-harvest residue input to cropland. Plant and Soil 93: 57-65.
Chen, H., Billen, N., Stahr, K., and Kuzyakov, Y. 2007. Effects of nitrogen and intensive mixing on decomposition of 14C-labelled maize (Zea mays L.) residue in soils of different land use types. Soil and Tillage Research 96: 114–123.
Couteautx, M., Bottner, P., and Berg, B. 1995. Litter decomposition, climate and litter quality. Trends in Ecology and Evolution 10: 63-66.
Crohn, D.M., and Valenzuela-Solano, C. 2003. Modeling temperature effects on decomposition. Journal of Environmental Engineering 129: 1149-1156.
Dijkstra, F.A., and Cheng, W. 2007. Moisture modulates rhizosphere effects on C decomposition in two different soil types. Soil Biology and Biochemistry 39: 2264–2274.
Dou, F. 2005. Long-term tillage, cropping sequence, and nitrogen fertilization effects on soil carbon and nitrogen dynamics. PhD thesis. Texas A & M University.
Fishman, J. 2003. Overview: Atmospheric Chemistry. In: Potter, T.D. and Colman, B.R. (Eds.), Handbook of Weather, Climate and Water, Atmospheric Chemistry, Hydrology and Social Impacts. A John Wiley and Sons, Inc., Publication. pp: 966.
Hansen, E.M., Christensen, B.T., Jensen, L.S., and Kristensen, K. 2004. Carbon sequestration in soil beneath long-term Miscanthus plantations as determined by 13C abundance. Biomass and Bioenergy 26: 97-105.
Hardy, J.T. 2003. Climate Change, Causes Effects and Solutions. John Wiley and Sons Ltd. pp. 247.
Haynes, R.J. 1986. Mineral nitrogen in the plant-soil system. Academic Press, Toronto.
Hemwong, S., Cadisch, G., Toomsan, B., Limpinuntana, V., Vityakon, P., and Patanothai, A. 2008. Dynamics of residue decomposition and N2 fixation of grain legumes upon sugarcane residue retention as an alternative to burning. Soil and Tillage Research 99: 84–97.
Hobbie, S.E. 1996. Temperature and plant species control over litter decomposition in Alaskan tundra. Ecological Monographs 66: 503–522.
Howard, D.M., and Howard, P.J.A. 1993. Relationships between CO2 evolution, moisture content and temperature for a range of soil types. Soil Biology and Biochemistry 25: 1537–1546.
Jenkinson, D.S., Adams, D.E., and Wild, A. 1991. Model estimates of CO2 emissions from soil in response to global warming. Nature 351: 304–306.
Kabba, B.S., and Aulakh, M.S. 2004. Climatic conditions and crop residue quality differentially affect N, P, and S mineralization in soils with contrasting P status. Journal of Plant Nutrition and Soil Science 167: 596–601.
Kätterer, T., Reichstein, M., Andre, O., and Lomander, A. 1998. Temperature dependence of organic matter decomposition: a critical review using literature data analyzed with different models. Biology and Fertility of Soils 27: 258–262.
Kirschbaum, M.U.F. 1995. The temperature dependence of soil organic matter decomposition, and the effect of global warming on soil organic C storage. Soil Biology and Biochemistry 27: 753–760.
Lal, R. 2002. Soil carbon dynamics in cropland and rangeland. Environmental Pollution 116: 353–362.
Lal, R., and Kimble, J.M. 1997. Conservation tillage for carbon sequestration. Nutrient Cycling in Agroecosystems 49: 243-253.
Larson, W.E., Clapp, C.E., Pierre, W.H., and Morachan, Y.B. 1972. Effects of increasing amounts of organic residues on continuous corn: II. Organic carbon, nitrogen, phosphorus and sulfur. Agronomy Journal 64: 204-208.
Lavelle, P., Blanchart, E., Martin, A., Martin, S., Spain, A., Toutan, F., Barois, I., and Schaefer, R. 1993. A hierarchical model for decomposition in terrestrial ecosystems: application to soils of the humid tropics. Biotropica 25: 130–150.
Li, C., Frolking, S., and Harriss, R.C. 1994. Modeling carbon biogeochemistry in agricultural soils. Global Biochemistry Cycles 8: 237-254.
Luna-Orea, P., Wagger, M.G., and Gumpertz, L.M. 1996. Decomposition and nutrient release dynamics of two tropical legume cover crops. Agronomy Journal 88: 758–764.
Lupwayi, N.Z., Clayton, G.W., O’Donovan, J.T., Harker, K.N., Turkington, T.K., and Soon, Y.K. 2007. Phosphorus release during decomposition of crop residues under conventional and zero tillage. Soil and Tillage Research 95: 231–239.
Meentemeyer, V. 1978. Macroclimatic and lignin control of litter decomposition rates. Ecology 59: 465–472.
Menzel, A. and Fabian, P. 1999. Growing season extended in Europe. Nature. 397: 659.
Nassiri Mahallati, M., and Koocheki, A. 2006. Analysis of agroclimatic indices of Iran under future climate change scenarios. Iranian Journal of Field Crops Research 4: 169-182. (In Persian with English Summary)
Parshotam, A., Saggar, S., Tate, K. and Parfitt, R. 2001. Modelling organic matter dynamics in New Zealand soils. Environment International 27: 111 –119.
Paul, E.A., and Clark, F.E. 1996. Soil Microbiology and Biochemistry. Academic Press, San Diego.
Paustian, K., Collins, H.P., and Paul, E.A. 1997. Management controls on soil carbon. In: Paul, E.A., Paustian, K., Elliot, E.T., Cole, C.V. (Eds) Soil Organic Matter in Temperate Agroecosystems: Long-term Experiments in North America. CRC Press, Boca Raton, Florida.
Paustian, K., Six, J., Elliott, E.T., and Hunt, H.W. 2000. Management options for reducing CO2 emissions from agricultural soils. Biogeochemistry 48(1): 147–163.
PeterJohn, W.T., Melillo, J.M., Bowles, F.P., and Steudler, P.A. 1993. Soil warming and trace gas fluxes: experimental design and preliminary flux results. Oecologia 93: 18–24.
Rosenzweig, C., and Parry, M.L. 1994. Potential Impacts of climate change on world food supply. Nature 367: 133-138.
Scorer, R.S. 2002. Air Pollution Meteorology. Horwood Publishing. pp. 150.
Swift, M.J., Heal, O.W., and Anderson, J.M. 1979. Decomposition in Terrestrial Ecosystems. Blackwell, Oxford.
Thorburn, P.J., Probert, M.E., and Robertson, F.A. 2001. Modelling decomposition of sugar cane surface residues with APSIM-Residue. Field Crops Research 70: 223-232.
Vazquez, R.I., Stinner, B.R., and McCartney, D.A. 2003. Corn and weed residue decomposition in northeast Ohio organic and conventional dairy farms. Agriculture, Ecosystems and Environment 95: 559–565.
Verma, S.B., Dobermann, A., Cassman, K.G., Walters, D.T., Knops, J.M., Arkebauer, T.J., Suyker, A.E., Burba, G.G., Amos, B., Yang, H., Ginting, D., Hubbard, K.G., Gitelson, A.A., and Walter-Shea, E.A. 2005. Annual carbon dioxide exchange in irrigated and rainfed-based agroecosystems. Agriculture and Forest Meteorology 131: 77-96.
Vitousek, P.M., Turner, D.R., Parton, W.J., and Sanford, R.L. 1994. Litter decomposition on the Mauna Loa environmental matrix, Hawai’i: patterns, mechanisms, and models. Ecology 75: 418–429.
Walkley, A., and Black, I.A. 1934. An examination of the Degtjareff method for determining organic carbon in soils: Effect of variations in digestion conditions and of inorganic soil constituents. Soil Science 63: 251-263.
Winkler, J.P., Cherry, R.S., and Schelsinger, W.H. 1996. The Q10 relationship of microbial respiration in a temperate forest soil. Soil Biology and Biochemistry 28: 1067–1072.
Yan, H., Cao, M., Liu, J., and Tao, B. 2007. Potential and sustainability for carbon sequestration with improved soil management in agricultural soils of China. Agriculture, Ecosystems and Environment 121: 325-335.
Yang, L., Pan, J., Shao, Y., Chen, J.M., Ju, W.M., Shi, X., and Yuan, S. 2007. Soil organic carbon decomposition and carbon pools in temperate and sub-tropical forests in China. Journal of Environmental Management 85: 690–695.
Zhou, X., Wan, S., and Luo, Y. 2007. Source components and interannual variability of soil CO2 efflux under experimental warming and clipping in a grassland ecosystem. Global Change Biology 13: 761–775.