References
- Bartholomew , W. V. 1965 . “ Mineralization and immobilization of nitrogen in the decomposition of plant and animal residues. ” . In Agronomy 10 Edited by: Bartholomew , W. V. and Clark , F. E. 287 – 306 . Madison , Wisconsin : Amer. Soc. Agron. . Soil Nitrogen.
- Bremner , J. M. 1965 . “ Nitrogen availability indexes ” . In Methods of soil analysis. Agronomy Edited by: Black , C. A. Vol. 9 , 1324 – 1345 . Madison , Wisconsin : Amer. Soc. Agron. . (2)
- Bremner , J. M. and Mulvaney , C. S. 1982 . “ Total nitrogen ” . In Methods of soil analysis, , 2nd edn. , Agronomy 9 Edited by: Page , A. L. 595 – 624 . Madison , Wisconsin : Amer. Soc. Agron. . (2)
- Gavlak , R. G. 1985 . Nitrogen mineralization in selected Montana soils. Bozeman : Montana State University . Ph.D. thesis. Dept. of Crop and Soil Science, Montana, U.S.A
- Haynes , R. J. and Sherlock , R. R. 1986 . “ Gaseous losses of nitrogen. ” . In Mineral nitrogen in the plant-soil system Edited by: Haynes , R. J. 242 – 302 . London : Academic Press, Inc. .
- Jansson , S. L. and Persson , J. 1982 . “ Mineralization and immobilization of soil nitrogen ” . In Nitrogen in agricultural soils. Agronomy Edited by: Stevenson , F. J. Vol. 22 , 229 – 252 . Madison , Wisconsin : Amer. Soc. Agron. .
- Keeney , D. R. and Bremner , J. M. 1966 . Determination and isotope-ratio analysis of different forms of nitrogen in soils. 4. Exchangeable ammonium, nitrate and nitrite by direct-distillation methods . Soil Sci. Soc. Amer. Proc. , 30 : 583 – 587 .
- Macduff , J. H. and White , R. E. 1984 . Components of the nitrogen cycle measured for cropped and grassland soil plant systems . Pl. Soil , 76 : 35 – 48 .
- Macduff , J. H. and White , R. E. 1985 . Net mineralization and nitrification rates in a clay soil measured and predicted in permanent grassland from soil temperature and moisture content . Pl. Soil , 86 : 151 – 172 .
- Macvicar , C. N. , De Villiers , J. M. , Loxton , R. F. , Verster , E. , Lambrechts , J. J.N. , Merryweather , F. R. , Le Roux , J. , Harmse , H. J. and Von , M. 1977 . Soil classification, a binomial system for South Africa. Science Bulletin No. 390. Dept. Agric. Techn. Services, Pretoria. 152
- NÄFE , D. , Schmidt , O. and Markgraf , G. 1983 . Zur Mineralisation des organisch gebundenen Bodenstickstoffs in Abhangigkeit von Bodentemperatur und Bodenfeuchtigkeit. I. Ergebnisse aus Inkubationsversuchen ohne Vegetation. Wiss. Z. Humboldt-Univ. Berlin, Math-naturwiss . Reihe , 32 : 453 – 461 .
- Nelson , D. W. and Sommers , L. E. 1982 . “ Total carbon, organic carbon and organic matter. ” . In Methods of soil analysis, Part 2. Chemical and microbiological properties. Amer. Soc. Agron., Madison, Wisconsin. Edited by: Page , A. L.
- Reuss , J. O. and Innis , G. S. 1978 . “ A grassland nitrogen flow simulation model. ” . In Grassland simulation model Edited by: Innis , G. S. 185 – 203 . Springer : Berlin .
- Snyman , H. A. 1982 . Die hidrologiese siklus en waterver- bruiksdoeltreffendheid van veld in verskillende suksessiestadia, in die sentrale Oranje-Vrystaat. M.Sc. Agric, thesis, University of the Orange Free State, Bloemfontein.
- Snyman , H. A. and Opperman , D. P.J. 1983 . Die invloed van vog- en ontblaringsbehandelings in hidrologiese eenhede op natuurlike veld van die sentrale Oranje-Vrystaat . Handl. Weidingsveren. S. Afr. , 18 : 124 – 130 .
- Wiltshire , G. H. 1986 . Effects of water supply on availability of ammonium and nitrate nitrogen in soil under grassland. Final Report, C.S.I.R., Pretoria.
- Wiltshire , G. H. and Laubscher , D. J. 1989 . Economical manual estimation of ammonium, nitrate and total inorganic nitrogen in soils . S. Afr. J. Plant Soil , 6 : 53 – 58 .
- Woodmansee , R. G. , Vallis , I. and Mott , J. J. 1981 . “ Grassland nitrogen. ” . In Terrestrial nitrogen cycles: processes, ecosystem strategies and management impacts Edited by: Clark , F. E. and Rosswall , T. 443 – 462 . Ecological Bulletins 33, Stockholm