The soil cover of the world stores more carbon than that present in biomass and in the atmosphere, so the depth and distribution of soil organic matter (SOM) might be important in point of carbon sequestration and climate change mitigation. Texture, among several other factors, plays an important role in the distribution of SOM. Most national and the main international soil classification systems (Soil Taxonomy, World Reference Base for Soil Resources) have a separate unit for high clay content soils on the highest level of classification, as Vertisols. Due to the high swelling clay content, these soils open deep cracks when they are dry. During the process called “pedoturbation”, the high SOM content surface material falls into the cracks, where it accumulates and mixes with subsoil, and enhances the accumulation of SOM in great depth. Although the effect of texture on the stabilization, distribution and properties of SOM have been investigated, only little information is available on SOM distribution in high clay content soils. The objective of the present study was to analyze the vertical distribution of SOM in high clay content soils of Hungary. Our results, based on the investigations of the Hungarian TIM database supported the hypothesis that high clay content soils store significantly more SOM and in greater depth than other soils under similar climatic conditions.
Batjes, N. H., 1996. Total carbon and nitrogen in the soils of the world. European Journal of Soil Science. 47. (2) 151–163.
Bot, A. & Benites, J., 2005. The importance of soil organic matter. Key to drought-resistant soil and sustained food and production. FAO Soils Bull. No. 80. Rome.
Buzás, I. (ed.), 1993. Soil and Agrochemistry Analysis Methods. 1. (In Hungarian) INDA 4231 Kiadó. Budapest.
Dobos, E. & Kobza, J., 2007. Soils of the Bodrogköz. In: Life between the rivers. Land use in the Bodrogköz. (Eds.: Dobos, E. & Terek, J. ) (In Hungarian) 39–47. Miskolci Egyetem.
Eswaran, H., van Den Berg, E. & Reich, P., 1993. Organic carbon in soils of the world. Soil Sci. Soc. Am. J. 57. 192–194.
Follett, R. F., 2001. Soil management concepts and carbon sequestration in cropland soils. Soil and Tillage Research. 61. 77–92.
Franzluebbers, A. J. et al., 1996. Active fractions of organic matter in soils with different texture. Soil Biol. Biochem. 28. 1367–1372.
Hassink, J. et al., 1993. Relationships between habitable pore space, soil biota and mineralization rates in grassland soils. Soil Biol. Biochem. 25. 47–55.
Hilinski, T. E., 2001. Century 5: Implementation of Exponential Depth Distribution of Organic Carbon in the CENTURY Model. Department of Soil and Crop Sciences, Colorado State University.
Jobbagy, E. G. & Jackson, R. B., 2000. The vertical distribution of soil organic carbon and its relation to climate and vegetation. Ecological Applications. 10. (2) 423–436.
Kay, B. D. & van den Bygaart, A. J., 2002. Conservation tillage and depth stratification of porosity and soil organic matter. Soil Till. Res. 66. 107–118.
Kovda, I., Chichagova, O. & Mora, C. I., 2005. Organic matter in a gilgai soil complex, southeastern Russia: chemical and isotopic compositions. Adv. Geoecol. 36. 45–56.
Kovda, I. et al., 2001. Radiocarbon age of Vertisols and its interpretation using data on gilgai complex in the North Caucasus. Radiocarbon. 43 . (2) 603–609.
MSZ-08 0210 77, 1978. Determination of the organic carbon content of soil. Hungarian Agricultural and Food standard. (In Hungarian) Budapest.
Sombroek, W. G., Nachtergaele, F. O. & Hebel, A., 1993. Amounts, dynamics and sequestrations of carbon in tropical and subtropical soils. Ambio. 22. 417–426.
TIM (Hungarian Soil Information and Monitoring Network), 1995. Methodology. (In Hungarian) Budapest.
Wilding, L. P. & Tessier, D., 1988. Genesis of Vertisols: Shrink-swell phenomena. In: Vertisols: Their Distribution, Properties, Classification and Management. (Eds. Wilding, L. P. & Puentes, R. ) Tech. Mono. No. 18. 55–79. Texas A&M Printing Center. College Station, TX.