References
- Ballenegger , R. 1958 . Methods of Soil Analysis Budapest : Mezőgazdasági Kiadó . (in Hungarian)
- Barabancíková , G. , Senesi , N. and Brunetti , G. 1997 . Chemical and spectroscopic characterization of humic acids isolated from different Slovak soil types . Geoderma , 78 : 251 – 266 .
- Blume , H.‐P. and Helsper , M. 1987 . Schätzung des Humusgehaltes nach der Munsell‐Farbhelligkeit . Zeitschrift für Pflanzenernährung und Bodenkunde , 150 : 354 – 356 .
- Bowman , R. A. 1997 . Field Methods to Estimate Soil Organic Matter Akron, CO : USDA‐ARS and USDA‐NRCS . (Conservation Tillage Fact Sheet no. 5)
- Bowman , R. A. , Guenzi , W. D. and és Savory , D. J. 1991 . Spectroscopic method for estimation of soil organic matter . Soil Sci. Soc. Am. J. , 55 : 563 – 566 .
- Buzás , I. 1988 . Methods of Soil and Nutrient Analysis, 2 Budapest : Mezogazdasági Kiadó . (in Hungarian)
- Environmental Instruments . 1988 . Anagas CD 98 Operating Instructions Leamington, , U.K : Environmental Instruments .
- Gieseking , J. E. 1975 . Soil Components Vol. 1 , New York : Springer‐Verlag . Organic components
- Guenzi , W. D. and Savory , D. J. 1991 . Spectroscopic method for estimation of soil organic matter . Soil Science Society of America Journal , 55 : 563 – 566 .
- Hodgson , J. M. 1974 . Rothamsted Experimental Station, Soil Survey Technical Monograph 5, Soil Survey, Harpenden . Soil Survey Field Hadbook ,
- Németh , T. 1996 . Organic Matter and Nitrogen Content of Hungarian Soils Budapest : MTA Talajtani és Agrokémiai Kutató Intézete . (in Hungarian)
- Pataki , L. and Zapp , E. 1972 . Analytical chemistry Budapest : Tankönyvkiadó . (in Hungarian)
- Stevenson , F. J. 1982 . Humus Chemistry New York : Wiley .
- Walkley , A. and Black , I. A. 1934 . An examination of the Degiareff method for determing SOM and a proposed modification of the chromic acid titration method . Soil Science , 37 : 29 – 38 .