EVALUATION OF NUTRIENTS AVAILABILITY BY APPLYING FERTILIZER AT DIFFERENT DOSES IN SOIL COLUMN

The issue of exchange processes, retention and leaching of ions in soil is far from being completely elucidated, most of the researches being conducted on pure materials and the organic-mineral complexes from soil differs significantly from those. In addition, details of soil nutrients availability rate are unknown, requiring fundamental research studies for each type of soil. In order to study the retention and migration processes it was developed an experiment on epicalcaric chernozem soil from Scânteia, IalomiĠa County for a number of cations and anions involved in plant nutrition. The retention and migration in soil of ammonium, nitrate, phosphate and potassium nutrient ions have been experimentally investigated by providing an experimental device that consisted in a series of glass columns filled with 100 g of soil air dried. A solution containing investigated ions, in different doses, was applied in soil by percolation. The soil columns experimental method allows us to determine the equations that describe the availability of nitrogen forms (ammonium and nitrate), phosphorus and potassium based on applied dose of fertilizer. The relation between the content in soil of mineral nitrogen (N-NH4 + and N-NO3 - ), potentially available phosphorus and potassium and applied dose of N, P and K indicate a highly significant correlation. Nutrient retention and leaching simulation processes by applying different doses of chemical fertilizers in soil allowed us to establish the available and accessible quantities, and to obtain the optimal levels of fertilizer required by crops.