Elsevier

Soil Biology and Biochemistry

Volume 26, Issue 9, September 1994, Pages 1221-1231
Soil Biology and Biochemistry

Effects of soil texture and grassland management on soil organic C and N and rates of C and N mineralization

https://doi.org/10.1016/0038-0717(94)90147-3Get rights and content

Abstract

The effects of soil texture and grassland management, i.e. rate of fertilizer N input, mowing vs grazing, and the number of years the site is under grass, on the amounts of soil organic C and N and on the rates of C and N mineralization were investigated.

A positive relationship was found between the amount of organic N in the soil and the clay + silt content. The relationship was affected by the groundwater table. There was a negative relationship between the percentage of soil N mineralizing during incubation and the clay + silt content of the soil. The amount of organic C was only positively correlated with soil texture in the soils with a high water table, but the relationship was less clear. Except for the groundwater table, differences in the C-to-N ratio of the soil organic matter in sandy soils confused the relationship of soil organic C with soil texture. Organic matter in podzol soils had C-to-N ratios between 15 and 20 while in other sandy soils the C-to-N ratio ranged from 10 to 18; in loams and clays the C-to-N ratio was ca 10. The percentage of soil C mineralizing in sandy soils was negatively correlated with the C-to-N ratio of the soil organic matter. The sandy soils with a C-to-N ratio 16 that were used for incubation contained black humus including small charcoal particles; both other sandy soils with a lower C-to-N ratio contained brown humus without visible charcoal particles. So we hypothesize that sandy soils with a high C-to-N ratio contained more inert C than sandy soils with a low C-to-N ratio.

The rate of N fertilization had no effect on soil organic C and N nor on the rates of C and N mineralization. Differences between the effects of grazing and mowing on soil organic C and N and the rate of C and N mineralization were very small and not very consistent.

Both the amounts of soil organic C and N found and the rates of C and N mineralization were significantly higher in old grassland (10 yr) than in young grassland (1–3 yr). The increases in the mineralization rates were larger than the increases in soil organic C and N.

References (34)

  • C.R. Clement et al.

    Leys and soil organic matter. II. The accumulation of nitrogen in soils under different leys

    Journal of Agricultural Science (Cambridge)

    (1967)
  • W.B. Deys

    The determination of total nitrogen in herbage samples

    IBS Jaarboek Mededelingen

    (1961)
  • E.T. Elliott et al.

    Let the soil work for us

  • G.C. Ennik et al.

    Effect of high nitrogen supply on sward deterioration and root mass

  • C. Feller et al.

    Effect of the texture on the storage and dynamics of organic matter in some low activity clay soils (West Africa, particularly)

    Cahier ORSTOM, serie Pedologie XXVI

    (1991)
  • M.J. Glendining et al.

    130 Years of inorganic nitrogen fertilizer applications to the Broadbalk wheat experiment: the effect on soil organic nitrogen

  • Cited by (257)

    View all citing articles on Scopus
    View full text