Definition of the criteria influencing on cultivation conditions of onions

Bulb onion is one of the most profitable crops among the vegetable group; this fact determines the relevance of the choice of the most suitable plots for its growing on light kastanozems. The purpose of the research is the scientific substantiation of methodical positions and the definition of reliable criteria for the assessment of land for the cultivation of bulb onions on intensive technology. The studies were conducted in the household «Khvan V.A.» in 2008-2015 on the following onion hybrids: Banco F1, Hilton F1, Exacta F1, Gladstone F1, Rossa di Firenze F1, Manas F1. During the study of crop rotations, natural soil fertility and fertilizers system the standard for vegetable growing methods of field experiments were used. The influence of growing conditions on yield of bulb onion was analyzed. The criteria of soil estimation, allowing predicting success of the growth and development of onion plants were determined. Correlation analysis showed that the granulometric composition of soils (r=0.79), natural fertility (0.71) and the system of fertilizers (r=0.54) have most significant influence on the formation of the yield. Found that rye and wheat, grown for green manure, are the best precursors on light kastanozems. It is revealed that onion is necessary to place the on medium loamy soils, where the highest productivity of hybrids is observed. The significant influence of the granulometric composition of soil on onion plants was substantiated. The best soil differences for this culture (light loam, medium loam), where productivity of crops is increased to 80-90 t/ha were selected. Criteria that determine the success of the cultivation of bulb onion on light kastanozems were identified, which will help to efficiently plan the crop rotation and predict the crop growth to increase production stability.