Relationship between phosphate- and potassium desorption and clay mineral composition of soils [antikvár]

Introduction The adsorption of phosphorus and potassium plays a great role in the mobilization of available plánt nutrients, and in the effectiveness of fertilizers. The characteristics and the degree of adsorption depend on the quality and quantity of soil colloids [10]. The quality and quantity of mineral colloids, clay minerals, are mainly responsible for adsorption because these components together with humic substances determine the processes of adsorption and desorption in soils. The clay mineral composition of Hungárián soils is known [7, 8] and is taken into account in the fertilizer advisory system, however, a knowledge of the causal relations would provide support in this respect. The method of electro-ultra-filtration (EUF) is widely used as well, so the theoretical foundations for the estimation of data may contribute to the better usage of EUF curves [1,2,4], The method of continuously fractionated desorption (FD), as a result of the further development of sorption studies [6], is more appreciable if the role of colloids in the adsorption process is properly known [3]. Materials and methods The 9 soil samples are from the ploughed layer of soils which are characteristic for large regions of the country,and are different in respect of clay mineral associations. The analytical data of soils are shown in Tables 1, 2 and 3. Before investigating the sorption and mobilization of phosphate and potassium, a part of the samples was treated with fertilizer. The data of the fertilizers used are shown Akadémiai Kiadó, Budapest Martinus Nijhoff/Dr. W. Junk Publishers