Map of Clay Mineral Associations in Hungarian Soils [antikvár]

Map ot Clay Mineral Associations in Hungárián Soils P. STEFANOVITS University of Agricultural Sciences, Gödöllő /HUNGARY/ The clay mineral associations in Hungary were studied during three periods. First, the soils belonging to the Corn Production System /Bábolna/ wsre sanpled and analyzed betwsen 1974 and 1981 in order to iirprove the national fertilization advisory service. Later, the mineral examinaticn was extended to other parts of the country by the Ministry of Agriculture and Food /1981-1984/, using funds granted for basic research by the Hungárián Academy of Sciences, while betwsen 1986 and 1988 a survey was made on soils developed cn hard rock parent material under forest vegetation. The results of the field surveys and laboratory analyses, covering 500 representative soil profiles, have been reported in a number of publications /STEFANOVITS, 1985/1986 STEFANOVITS and DOMBÓVÁRI, 1985, 1986a, 1986b; STEFANOVITS, BODOR and VARJÚ, 1978; STEFANOVITS, KÁlMN and KÓNYA, 1985; STEFANOVITS et al. , 1985/. The present paper gives a summary of these reports, complemented with new results and with conclusions drawn from the data. IWcthods The examination system was compiled in accordance with the desire to inprove the national advisory service on potassium and nitrogén fertilization. The investigations can be divided into three parts: -Basic analyses /including the measurement of nutrient element content/ of the totál soil material; determination of the mineral carposition of the soils using the X-ray diffraction method; -Mineral conposition of the crystalline phase of the clay fraction separated from the soil, based on the X-ray üifiraction curves ot the oriented samples treated with magnesium, ethylene glycol, KC1 and NH.C1; -Measurerrent of the cation exchange capacity of the clay fraction; determination of the totál potassium content of the clay fraction; thermal examination of the clay fraction, with the construction of DTA, DTG and TG curves. Nine types of clay mineral associations were distinguished, based on the results of these examinations. These nine types are the mapping units used in the map of clay mineral associations. The map of clay mineral associ-