Effect of Autumn Application of Different Doses and Types of Nitrogen Fertilizers on Post-Sunflower-Sown Winter Wheat Yield

Аннотация

Abstract: Currently, the demand for grain products is growing rapidly. However, due to different circumstances, the areas of optimal predecessors of winter cereals are decreasing, instead, the areas after such predecessors as sunflower grow. Because of this, farmers fail to harvest stable grain yields. Nitrogen fertilization is one of the most effective methods of managing the growth and development of winter wheat plants and increasing the crop yield. Several studies demonstrated the equivalence of autumn and spring application of nitrogen fertilizers on wheat. However, the issue of autumn nitrogen fertilization has not been sufficiently studied, especially for the eastern forest-steppe of Ukraine. Our purpose was to determine the yield of post-sunflower-sown winter bread wheat depending on different doses and types of nitrogen fertilizers applied in autumn. The design of the field experiments included 13 variants with three fertilizers (ammonium nitrate, urea, ammonium sulfate) applied at N₃₀, N₆₀, N₉₀, and N₁₂₀ on primary nutrient basis after sunflower as a forecrop. Autumn fertilization of wheat crops significantly increased the yield. The application of ammonium nitrate and urea at N₆₀ and ammonium sulfate at N₉₀ was the most effective variant of autumn fertilization of winter wheat, as it yielded 49, 46, and 46% more, respectively, compared to the control. At a low dose of nitrogen (N₃₀), the largest gain in the yield (31–34%) was achieved with ammonium nitrate and ammonium sulfate, while urea at this dose was less effective. The application of N₁₂₀ had no advantages compared to lower doses of autumn-applied nitrogen fertilizers, regardless of the fertilizer type.