Soil organic C sequestration and stabilization in karstic soils of Yucatan
Tóm tắt
The tropical semiarid soils of northwestern Yucatan, Mexico, haveexceptionally high organic matter (OM) contents, between 50 and 150 g Ckg−1. The soils are formed on limestone and form amosaic of shallow black lithosols surrounding rock outcrops and deeper redrendzinas at slightly lower relief. Traditionally, these soils were managedunder shifting cultivation with an uncommonly short cultivation period of only2years followed by a long bush fallow. We examined OM mineral associationsusing size and density fractionations of two soils after 1 and 12 years offallow in a search for factors responsible for the high OM stability, shortcultivation period and poor productivity. Light-fraction OM accounted for up to38% of total soil OM and was responsible for almost all the OM accretion duringfallow. Red soils contained half as much OM as black soils. Lower average OMcontents of silt-size aggregates of red soils were due to a lower proportion ofOC-rich agregates, not to differences in composition of individual aggregateclasses. Expandable clays were practically absent in both soil types andsesquioxides were not related to OM contents or stability. Fine-sized secondarycarbonates, undetectable to X-ray, impreganted light fraction OM and stabilizedaggregates, and may be the principal cause of the OM accumulation.Mineralisation of coarse OM accumulated during fallow was impeded in bothsoils,but to a greater extent in the more calcareous black soils, so that relativelyundecomposed OM accumulates to well above the levels that are typical for othersemiarid tropical soils. Limited OM turnover will limit nutrient release, whichmay limit the agricultural productivity.
Tài liệu tham khảo
Barnhisel R.I. and Bertsch P.M. 1989. Chlorites and hydroxy-interlayered vermiculite and smectite. In: Dixon J.B. and Weed S.B. (eds), Minerals in Soil Environments. 2nd edn. Soil Science Society of America, Madison, WI, USA, pp. 729–788.
Barke M. 1987. Yucatan, Mexico: dimensions of development 1970–1980. Geography 1987: 64–67.
Cambardella C.A. and Elliott E.T. 1992. Physical isolation of organic matter fractions from grassland soil. Soil Sci. Soc. Am. J. 56: 777–783.
Cambardella C.A. and Elliott E.T. 1994. Carbon and nitrogen dynamics of soil organic matter fractions from cultivated grassland soils. Soil Sci. Soc. Am. J. 58: 123–130.
Christensen B.T. 1992. Physical fractionation of soil and organic matter in primary particle size and density separates. Adv. Soil Sci. 20: 2–90.
Cole C.V., Stewart J.W.B., Ojima D.S., Parton W.J. and Schimel D.S. 1989. Modelling land use effects of soil organic matter dynamics in the North American Great Plains. In: Clarholm M. and Bergström L. (eds), Ecology of Arable Land. Kluwer Academic Publishers, Dordrecht, The Netherlands, pp. 89–98.
Dixon J.B. 1989. Kaolin and serpentine group minerals. In: Dixon J.B. and Weed S.B. (eds), Minerals in Soil Environments. 2nd edn. Soil Science Society of America, Madison, WI, USA, pp. 467–525.
Gee W.G. and Bauder J.W. 1986. Particle-size analysis. In: Klute A. (ed.), Methods of Soil Analysis, Part 1. Agronomy Monograph 9. 2nd edn. Agronomy Society of America, Soil Science Society of America, Madison, WI, USA, pp. 383–411.
Gregorich E.G. and Ellert B.H. 1993. Light fraction and macroorganic matter in mineral soils. In: Carter M.R. (ed.), Soil Sampling and Methods of Analysis. Canadian Society of Soil Science. Lewis Publishers, Boca Raton, FL, USA, pp. 397–407.
Hsu P.H. 1989. Aluminum oxides and oxyhydroxides. In: Dixon J.B. and Weed S.B. (eds), Minerals in Soil Environments. 2nd edn. Soil Science Society of America, Madison, WI, USA, pp. 331–378.
Isphording W.C. 1974. Weathering of Yucatan limestones. In: Weidie A.E. (ed.), Field Seminar on Water and Carbonate Rocks of the Yucatan Peninsula. Geological Society of America Guidebook FT-2., pp. 78–93.
Isphording W.C. 1978. Mineralogical and physical properties of Gulf Coast limestone soils. Gulf Coast Assoc. Geol. Soc. Trans. 28: 201–214.
Isphording W.C. 1984. The clay of Yucatan Mexico: a contrast in genesis. In: Singer A. and Galan E. (eds), Palygorskite-sepiolite: Occurrences Genesis and Uses. Elsevier Science Publishers, Amsterdam, The Netherlands, pp. 59–73.
Jastrow J.D. 1996. Soil aggregate formation and the accrual of particulate and mineral-associated organic matter. Soil Biol. Biochem. 28: 665–676.
Jastrow J.D., Boutton T.W. and Miller R.M. 1996. Carbon dynamics of aggregate-associated organic matter estimated by carbon-13 natural abundance. Soil Sci. Soc. Am. J. 60: 801–807.
Kunze G.W. and Dixon J.B. 1986. Pretreatment for mineralogical analysis. In: Klute A. (ed.), Methods of Soil Analysis. Part 1. Agronomy Monograph 9. 2nd edn. Agronomy Society of America, Soil Science Society of America, Madison, WI, USA, pp. 91–100.
McKeague J.A. and Day J.H. 1966. Dithionite-oxalate extractable Fe and Al as aids in differentiating various classes of soils. Can. J. Soil Sci. 46: 13–22.
Oades J.M. 1984. Soil organic matter and structural stability: Mechanisms and implications for management. Plant Soil 76: 319–337.
Parfitt R.L., Theng B.K.G., Whitton J.S. and Shepherd T.G. 1997. Effects of clay minerals and land use on organic matter pools. Geoderma 75: 1–12.
Parfitt R.L., Yuan G. and Theng B.K.G. 1999. A 13C-NMR study of the interactions of soil organic matter with aluminium and allophane in podzols. Euro. J. Soil Sci. 50: 695–700.
Perez Z.O., Uribe V.G. and Navarrete O.R. 1981. The “Milpa”, an ancient agricultural system of Yucatan, Mexico. In: Agronomy Abstract. Agronomy Society of America, Madison, WI, USA, pp. 44–45.
Quinones H. 1975. Soil study area 4. Intrazonal soils of northern Yucatan Peninsula. In: DePablo L. (ed.), Guidebook FT-4. 1975. Int. Clay Conf., Univ. Nac. de Mexico, Mexico, pp. 70–93.
Saggar S.A., Parshotam A., Sparling G.P., Feltham C.W. and Hart P.B.S. 1996. 14C-labelled ryegrass turnover and residence times in soils varying in clay content and mineralogy. Soil Biol. Biochem. 28: 1677–1686.
Shang C. and Tiessen H. 1997. Organic matter lability in a tropical Oxisol: evidence from shifting cultivation, chemical oxidation, particle size, density and magnetic fractionations. Soil Sci. 162: 795–807.
Shang C. and Tiessen H. 1998. Stabilization of organic matter in two semi-arid tropical soils: size, density and magnetic separations. Soil Sci. Soc. Am. J. 62: 1247–1257.
Shang C. and Tiessen H. 2000. Carbon turnover and carbon-13 natural abundance in organic-mineral fractions of a tropical dry forest soil under cultivation. Soil Sci. Soc. Am. J. 64: 2149–2155.
Shang C. and Tiessen H. 2001. Sequential versus parallel fractionation of organic matter in tropical soil separates using metatungstate solution. Soil Biol. Biochem. 33: 259–262.
Six J., Elliott E.T., Paustian K. and Doran J.W. 1998. Aggregation and soil organic matter accumulation in cultivated and native grassland soils. Soil Sci. Soc. Am. J. 62: 1367–1377.
Sollins P., Homann P. and Caldwell B.A. 1996. Stabilization and destabilization of soil organic matter: mechanisms and controls. Geoderma 74: 65–105.
Thomas R.L., Sheard R.W. and Moyer J.R. 1967. Comparison of conventional and automated procedures for nitrogen, phosphorus, and potassium analysis of plant material using single digest. Agron. J. 59: 240–243.
Teran S. and Rasmussen C.H. 1994. La Milpa de los Mayas. DANIDA, Merida, Mexico.
Tiessen H., Salcedo I.H. and Sampaio E.V.S.B. 1992. Nutrient and soil organic matter dynamics under shifting cultivation in semi-arid northeastern Brazil. Agri. Ecosyst. Environ. 38: 139–151.
Tiessen H., Cuevas E. and Chacon P. 1994. The role of soil organic matter stability in soil fertility and agricultural potential. Nature 371: 783–785.
Tisdall J.M. and Oades J.M. 1982. Organic matter and water-stable aggregates in soils. J. Soil Sci. 33: 141–163.
Turchenek L.W. and Oades J.M. 1979. Fractionation of organo-mineral complexes by sedimentation and density techniques. Geoderma. 21: 311–343.
Weisbach C., Tiessen H. and Jimenez-Osornio J.J. 2002. Soil fertility under shifting cultivation (Milpa) in Yucatan. Agronomie 22: 113–123.