Hortensia RĂDULESCU None
The study presents the results of soil treatment with industrial mineral residue on the nutrient soil content. Two industrial residues were tested by treating luvosoil, a low fertile acid soil, with different doses of residue. These two mineral sources have resulted from the magnesium products industry and contain in their composition magnesium and calcium as well as low contents of trace elements such as iron, copper, manganese and zinc. The residues have resulted in the industrial process of manufacturing magnesium compounds from dolomites. The difference between the two residues types lies in the double magnesium content, established for the wall crusts of the reactor. Because of their alkaline reaction and nutritive elements content, the two residue types can be revaluated in agriculture. The experimental alternatives consist of  four different doses from each residue, without or  with nitrogen addition (ammonium nitrate) to the soil. In order to establish the effects of soil treatment with residue, the available content of soil nutrients  were determined. The available nutrient soil content was analysed by using the EDTA extraction method for calcium and magnesium along with atomic absorption spectrophotometry. After extraction by Egner-Riehm-Domingo method phosphorus was determinated by UV-VIS spectroscopy and potassium by atomic absorption spectroscopy.The trace elements were analysed using the acid mixture digestion method followed by absorbtion spectrometric determination. The results show that increasing the residue doses, the available potassium content rises. Nitrogen supplement increase the potassium content  till 49%.The available calcium content rises proportional with the administered residue doses for both types. Nitrogen contribution increases the values by 13% for residue A and 63 % for residue B. The dynamics of available magnesium content is similar to that of calcium. The increases represent 20 % for residue A and 75% for residue B. The originality of this paper consists in the utilization of the residues  resulted from the magnesium products industry in agriculture as soil fertilizer. The importance of this study lies in the fact that, on the basis of the obtained results, a new technology to improve soil quality can be conceived by specifying the suitable dose, usage manner and application frequency of the tested residues. The usefulnes of the research is represented by the utilization of large amounts of residues, obtained from the magnesium compounds industry,as fertilizer for low fertile soils.
fertilizer, mineral residues, soil, available nutrient content, soil quality
Presentation: oral