Abstract
The use of annually sown pastures to provide winter forage is common in dairy farming in many regions of the world. Loss of organic matter and soil structural stability due to annual tillage under this management may be contributing to soil degradation. The comparative effects of annual ryegrass pastures (conventionally tilled and resown each year), permanent kikuyu pastures and undisturbed native vegetation on soil organic matter content, microbial size and activity, and aggregate stability were investigated on commercial dairy farms in the Tsitsikamma region of the Eastern Cape, South Africa. In comparison with soils under sparse, native grassy vegetation, those under both annual ryegrass and permanent kikuyu pasture had higher soil organic matter content on the very sandy soils of the eastern end of the region. By contrast, in the higher rainfall, western side, where the native vegetation was coastal forest, there was a loss of organic matter under both types of pasture. Nonetheless, soil organic C, K2SO4-extractable C, microbial biomass C, basal respiration, arginine ammonification and fluorescein diacetate hydrolysis rates and aggregate stability were less under annual than permanent pastures at all the sites. These results reflect the degrading effect of annual tillage on soil organic matter and the positive effect of grazed permanent pasture on soil microbial activity and aggregation. Soil organic C, microbial biomass C, K2SO4-extractable C, basal respiration and aggregate stability were significantly correlated with each other. The metabolic quotient and percentage of organic C present as microbial biomass C were generally poorly correlated with other measured properties but negatively correlated with one another. It was concluded that annual pasture involving conventional tillage results in a substantial loss of soil organic matter, soil microbial activity and soil physical condition under dairy pastures and that a system that avoids tillage needs to be developed.
Similar content being viewed by others
References
Alef K, Kleiner D (1987) Applicability of arginine ammonification as an indicator of microbial activity in different soils. Biol Fertil Soils 5:148–151
Anderson JPE (1982) Soil respiration. In: Page AL (ed) Methods of soil analysis, part 2, 2nd edn. Soil Science Society of America, Madison, Wisc., pp 837–871
Baldock JA, Nelson PN (2000) Soil organic matter. In: Sumner ME (ed) Handbook of soil science. CRC Press, Boca Raton, Fla., pp B25–B84
Blakemore LC, Searle PL, Daly BK (1972) Methods for chemical analysis of soils. New Zealand Soil Bureau Report 10A. Government Printer, Wellington
Bolan NS, Baskaran S, Thiagarajan S (1996) An evaluation of the methods of measurement of dissolved organic carbon in soils, manures, sludges and stream water. Commun Soil Sci Plant Anal 27:2723–2737
Bonde TA, Nielsen TH, Miller M, Sørensen J (2001) Arginine ammonification assay as a rapid index of gross mineralization in agricultural soils. Biol Fertil Soils 34:179–184
Dalal RC (1998) Soil microbial biomass—what do the numbers really mean? Aust J Exp Agric 38:649–665
Doran JW, Sarrantonio M, Liebig MA (1996) Soil health and sustainability. Adv Agron 56:1–54
Fenton TE, Brown JR, Mausbach MJ (1999) Effects of long-term cropping on organic matter content of soils: implications for soil quality. In: Lal R (ed) Soil quality and soil erosion. CRC Press, Boca Raton, Fla., pp 95–124
Franzluebbers AJ, Zuberer DA, Hons FM (1995) Comparison of microbiological methods for evaluating quality and fertility of soil. Biol Fertil Soils 19:135–140
Gregorich EG, Carter MR, Doran JW, Pankhurst CE, Dwyer LM (1997) Biological attributes of soil quality. In: Gregorich EG, Carter MR (eds) Soil quality for crop production and ecosystem health. Elsevier, Amsterdam, pp 81–113
Haynes RJ (1993) Effect of sample pre-treatment on aggregate stability measured by wet sieving or turbidimetry on soils of different cropping histories. J Soil Sci 44:261–270
Haynes RJ (1999a) Labile organic matter fractions and aggregate stability under short-term, grass-based leys. Soil Biol Biochem 31:1821–1830
Haynes RJ (1999b) Size and activity of the soil microbial biomass under grass and arable management. Biol Fertil Soils 30:210–216
Haynes RJ (2000) Labile organic matter as an indicator of organic matter quality in arable and pastoral soils in New Zealand. Soil Biol Biochem 32:211–219
Haynes RJ, Beare MH (1996) Aggregation and organic matter storage in meso-thermal, humid soils. In: Carter MR, Stewart BA (eds) Advances in soil science. Structure and organic matter storage in agricultural soils. CRC Press, Boca Raton, Fla., pp 213–262
Haynes RJ, Williams PH (1993) Nutrient cycling and soil fertility in the grazed pasture ecosystem. Adv Agron 49:119–199
Insam H, Domsch KH (1998) Relationship between soil organic carbon and microbial biomass on chronosequences of reclamation sites. Microb Ecol 15:177–188
Insam H, Haselwanter K (1989) Metabolic quotient of soil microflora in relation to plant succession. Oecologia 79:174–178
Janzen HH, Campbell CA, Ellert BH, Bremer E (1997) Soil organic matter dynamics and their relationship to soil quality. In: Gregorich EG, Carter MR (eds) Soil quality for crop production and ecosystem health. Elsevier, Amsterdam, pp 277–291
Kassim G, Martin JP, Haider K (1982) Incorporation of a wide variety of organic substrate carbons into the soil biomass as estimated by the fumigation procedure. Soil Sci Soc Am J 45:1106–1112
Ladd JN, Foster RC, Nannipieri P, Oades JM (1996) Soil structure and biological activity. In: Stotzky G, Bollag JM (eds) Soil biochemistry, vol 9. Dekker, New York, pp 23–78
Sarathchandra SU, Perrott KW, Boase MR, Waller JE (1998) Seasonal changes and the effects of fertilizers on some chemical, biochemical and microbiological characteristics of high-producing pastoral soil. Biol Fertil Soils 6:328–335
Schnürer J, Rosswall T (1982) Fluorescein diacetate hydrolysis as a measure of total microbial activity in soil and litter. Appl Environ Microbiol 43:1256–1261
Soil Classification Working Group (1991) Classification. A taxonomic system for South Africa. Soil and Irrigation Research Institute, Department of Agricultural Development, Pretoria
Tate RL (1995) Soil microbiology. Wiley, New York
Tisdall JM, Oades JM (1982) Organic matter and water stable aggregates in soils. J Soil Sci 33:141–163
Vance ED, Brookes PC, Jenkinson DS (1987) An extraction method for measuring microbial biomass C. Soil Biol Biochem 19:703–707
Wardle DA, Ghani A (1995) A critique of the microbial metabolic quotient (qCO2) as a bioindicator of disturbance and ecosystem development. Soil Biol Biochem 27:1601–1610
Acknowledgements
We are indebted to the farm owners and managers who gave us access to their fields, and the Tsitsikamma Milk Producers Group who funded the research and provided a postgraduate student bursary to the senior author.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Milne, R.M., Haynes, R.J. Soil organic matter, microbial properties, and aggregate stability under annual and perennial pastures. Biol Fertil Soils 39, 172–178 (2004). https://doi.org/10.1007/s00374-003-0698-y
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00374-003-0698-y