PROPERTIES OF COATED AMMONIUM-NITRATE WIT H DIFFERENT SOLUBILITY

In gemination test, leaching experiments, and three years' pot experim ents the behaviour of coated nitrochalks with different half-time of s olubility was investigated. Coated fertilizers were compared with a wi de used nitrochalk in all experiments. The basic properties and symbol s of applied fertilizers are summarized in Tab. I. Clearly positive ef fect of coated fertilizers application was not found, but results of g emination test of the lettuce after application of coated nitrochalks (Fig. 1) and leaching experiment on sandy soil (Figs 3 and 5) showed b etter properties of coated samples. The results of leaching test on me dium soil were not so explicit (Figs 2 and 4). The positive effect on the yield and nitrate accumulation in oat plant was only found on the treatments with highest nitrogen rate (Tabs II and III). Content of dr y matter of silage oat was not influenced by tested fertilizers. In th e case of low and optimal nitrogen rate the yield depression was found out due to very low nitrogen release from fertilizer shell. Nitrogen content of the shell was included into the total nitrogen rate. A long er half time of solubility had not a positive effect in our experiment s.