Clay Mineral Content of Soils and Fertilizer Use [antikvár]

Clay Mineral Content of Soils and Fertilizer Use P. STEFANOVITS University of Agricultural Sciences, Gödöllő /Hungary/ Considerable differences are found if the fertilizer consumption of Hungary is corpared to the fertilization practice in other countries. In countries which apply similar doses of fertilizer, the plánt production is often more econcmical, i.e. the efficiency of the fertilizers is higher. At the same time the application of nitrogén, phosphorus and potassium fertilizers increases at more or less the same rate, while in Hungary the application of potassium exceeds that of nitrogén and phosphorus fertilizers to an ever greater extent. Consequently, the practice of potassium fertilization in Hungary needed revision and reevaluation. In addition, the characterization of the clay mineral conposition and occurrence of various types of soils in Hungary alsó became necessary if potassium fertilization itself and the national fertilization advisory service were to be iirproved. Materials and methods The samples were collected from 300 representative soil profi les. The examinations were always made on oonplete soil profiles, so the processes taking place in the soils could alsó be studied. The clay fraction was separated, after which it was treated with magnesium, potassium chloride and ethylene glycol. X-ray diffraction analysis of these orientated sanples was then carried out. A method was elaborated for the semi-quantitative evaluation of the clay mineral associations. The cation exchange capacity and the totál potassium content of the clay fraction were alsó determined. The X-ray diffraction analysis of the totál soil sanple was alsó carried out, and periclase was used as an internál standard for the quantitative evaluation. Maps /in scale of 1:500 000/ of clay mineral associations and of potassium-fixing clay minerals in the soils of Hungary have been prepared over the last ten years, taking into consideration not only the field surveys and laboratory results but the available soil, geological, geonorphological and groundwater maps. Results and discussion Clay mineral associations in the soils of Hungary Eight kinds of clay mineral associations were distinguished in soil sanples representing the ploughed layer. A 25-50% proportion of clay minerals is regarded as noderate /Table 1/. The map indicates both the clay