Decomposition of the organic materials from hill soils and pastures I.—Incubation method for studying the mineralisation of carbon, nitrogen and phosphorus
✍ Scribed by M. J. S. Floate; C. J. W. Torrance
- Publisher
- John Wiley and Sons
- Year
- 1970
- Tongue
- English
- Weight
- 542 KB
- Volume
- 21
- Category
- Article
- ISSN
- 0022-5142
No coin nor oath required. For personal study only.
✦ Synopsis
Plant materials and sheep faeces from 2 hill sites were used to develop a method suitable for measuring the production of COz and mineral N and P during incubation with aqueous soil extract. Variation in sample size (2 or 5 g) and source of the extract inoculum (from AO or A1 soil horizon) had little effect on the results, but production of mineral N and P"was reduced in the absence of any inoculum. Nitrogen was lost during incubation in both open and closed systems, but by absorption of evolved ammonia in 50% sulphuric acid almost complete recovery of nitrogen was achieved in the closed system. More NH3, nitrate-N and COz were produced at 25 % moisture-holding capacity than at loo%, but variation in moisture content had little effect on ammonium-N production. Lowering the incubation temperature resulted in reduced production of COz and mineral-N and P, but sheep faeces produced most ammonium-N at 10".
Experimental Samples
Preliminary experiments were conducted with samples of hill pasture herbage, and freshly voided sheep faeces, collected from an area of Darleith soils at 1200 ft near Jedburgh, Roxburghshire.lZ The materials used were as follows : herbage from Agrostis-Festuca pasture ; herbage from Nardus pasture; and sheep faeces collected from an area of dominantly Agrostis-Festuca pasture.
Subsequent experiments were carried out using plant materials obtained from untreated areas of hill pastures on soils of the Sourhope Associatiod2 at 1000 ft on the Hill Farming Research Organisation's Experimental Farm at Sourhope, Roxburghshire. Three replicates of two cutting treatments (A and B) were applied to 800 m2 blocks of Agrostis-Festuca and Nardus pastures which had been trimmed in Spring, and from which grazing was excluded for the period of the experiment. Herbage was either cut in October only (A) or cut at monthly intervals between May and October (B). After each cut the herbage was rapidly dried at 80" and retained for feeding. The dry grass from