Quantitative and qualitative evaluation of autumn-sown sunflower growth

Under warm climate conditions it is possible, and this has been proved by the results of multiple field experimental studies, to grow the winter varieties of sunflower. Considering that sunflower is the most widespread and important technical (oil) crop, widely used in the production of oil for food and technical purposes, its cultivation should be of the utmost importance and perspective. However, in general, successful cultivation of sunflower, both regular varieties and winter crops, depends on many natural and climatic factors, such as temperature, amount of heat during the growing season, availability of moisture, soil type and crop rotation used, as well as the required plant nutrition rate. Our experimental agronomic field studies have shown positive results, allowing us to recommend this particular type of crop, i.e., autumn-sown sunflower, for mass production. However, the technology of growing the winter sunflower has a number of its own features. Thus, there is a need for pre-sowing treatment of its seeds with a water-repellent preparation at a soil temperature, not exceeding 2-3 ºC. Sowing should exclude the process of soil compaction by a seed drill rolling devices, which eliminates rapid seed germination. The results of the field measurements showed that, in contrast to the conventional varieties, the autumn-sown sunflower plants do not have significant differences in the uniformity of their arrangement in the rows of crops, which indicates almost the same germination, as well as in the height of the plants themselves. The results of statistical evaluation showed that at a statistical significance level of 0.05 it was established that the null hypothesis about the equality of the mean values and variances of the fluctuations of these parameters for both types of sunflowers is not significantly rejected. Yet, other measurements showed that the diameter of the autumn-sown sunflower heads is on average 1.32 cm larger than that of the regular ones. Therefore, it has been established that the dispersion and frequency of oscillations of this parameter are higher. On the whole, according to the results of the conducted field experimental study, it turned out that the yield of the autumn-sown sunflower, recorded at a statistical significance level of 0.05, was 2.6 cwt·ha⁻¹, higher. If we take into account the fact that the harvesting period for the autumn-sown sunflower is earlier, on average by 40 days, then the efficiency of its production is more than obvious.