Yield of apple winter varieties depending on fertilizer doses in conditions of leashed сhernozem of Stavropol upland

Abstract

In an experiment, within the framework of the developed research methodology, it has been studied the effect of single (N60P60K60), double (N120P120K120) and triple (N180P180K180) doses of mineral fertilizers on the productivity parameters of the autumn varieties of Florin and Liberty apple trees cultivated in the conditions of the educational and experimental farm of the Stavropol State University. According to the results obtained for these varieties, the highest average fruit weight in the experiment, which exceeded the results of other nutritional backgrounds by 8.7-23.9 g, was noted when a triple dose of fertilizer was applied. As a result of the surveys, it was found that the highest yield on average for the considered varieties was observed when a double dose of fertilizer was applied, exceeding the rest of the nutrition by 0.4-3.9 t/ha. It was noted that the difference in the average weight of fruits and yield in the variants with double and triple doses of fertilizer was within the experimental error. According to the results of the analysis of the biochemical composition of the fruits, one can note the advantage of options with double saturation of fertilizers for all considered parameters. The content of nitrate nitrogen in fruits is directly proportional to the saturation of the studied doses of fertilizer, but in all cases the parameter was lower than the maximum permissible concentrations of nitrates in fresh fruits, which positively characterizes the use of these doses of mineral fertilizers in modern intensive orchards.