SEED COTTON YIELD AND YIELD COMPONENTS AFFECTED BY THE MINERAL FERTILIZATION AND THE WEATHER CONDITIONS

The aim of the study was to determine the reaction of cotton to different fertilizer rates and combinations under the influence of different weather conditions. In 1966 a long-term stationary fertilizer experience was established at the Field Crop Institute in Chirpan, Bulgaria. The results represent 2019 and 2020 crop years. The experiment was based on two-field crop rotation. Cotton variety Philipopolis was grown with durum wheat, without irrigation. The following doses of nitrogen and phosphorus were applied: 40, 80, 120 and 160 kg ha(-1). Potassium fertilizer was used at a rate of 80 kg ha. N0P0K0 was adopted as a control. N160P40 had the greatest effect on seed cotton yield and boll weight; N160P80 - lint yield and ginning; N160P120 - plant height; N120P120 - number of boll per plant and N40P80 - fiber length. The strongest correlation was observed between lint yield and ginning (P = 0.902(***)), and fiber length was negatively related to all traits. Yield and yield components can be strongly influenced by different weather conditions.