The effect of differentiated application of nitrogen fertilizers on the yield of potatoes (Solanum tuberosum L.) of the snegir variety

Relevance.. Potatoes belong to crops that place high demands on the level of mineral nutrition. He needs nitrogen especially badly. Timely introduction of calculated doses of nitrogen fertilizers based on the results of photometric diagnostics of plants allows rational use of fertilizers and increase potato yields. Material and methods. The studies were carried out in the conditions of the Central region of the Non-Chernozem zone on sod-podzolic medium loamy soils with a high content of mobile forms of phosphorus and potassium and a low humus content (1,9%). The object of research is an early-ripening potato variety Bullfinch. To recalculate the dose of nitrogen fertilizing, photometric diagnostics of crops was carried out with an optical sensor GreenSeeker RT200. Additionally, before and after fertilizing, a manual N-tester Yara was examined. Before the main harvest, a control digging of tubers was carried out to determine the structure of the crop with division into 4 fractions. Results. It was found that the introduction of nitrogen fertilizers into the top dressing during the closing phase of the tops in the form of ammonium nitrate has a generally favorable effect on the growth and development of potatoes. This is confirmed by the results of photometric diagnostics performed by the Yara N-tester during the withering phase of the tops. When applying top dressing with a fixed dose, the N-tester readings were 21,7% higher than in the control, and when applying fertilizers with a differentiated dose by 25,6%. The yield of potato tubers increased when applying a fixed dose of top dressing by 10,8%, differentiated by 14,5% compared to the control.