EFFECTS OF FERTILIZER APPLICATION ON WINTER WHEAT GROWTH UNDER HYDRIC STRESS CONDITIONS

Winter wheat (Triticum aestivum) represents a significant cereal crop in the northeastern region of Romania.Wheat production in this area is frequently constrained by drought stress conditions and low efficiency in the utilization of chemical fertilizers under water deficit scenarios.Consequently, effective water management practices for agricultural productivity in regions experiencing water scarcity necessitate the implementation of innovative and sustainable strategies.In order to evaluate the impact of nitrogen fertilizers and biostimulants on the growth and yield of winter wheat, two experiments were conducted at the Didactic Station of Iai, affiliated with the Iai University of Life Sciences, during the period 2020-2023.The first experiment assessed the sensitivity of winter wheat to the application of five biostimulant fertilizers.The second experiment investigated the response of winter wheat to four slow-release nitrogen fertilizer treatments.The application of biostimulants, particularly Brio N, significantly influences fertilizer efficiency by promoting nutrient uptake through plant roots, enhancing plant tolerance to water stress, and improving the plant's ability to metabolize essential nutrients.Additionally, the use of nitrogen-based foliar fertilizers such as N3 positively impacts plants experiencing hydric stress.Specifically, it enhances the plants' tolerance to water scarcity, boosts photosynthetic activity, and supports protein synthesis.Furthermore, soil-applied liquid nitrogen fertilizers, represented by N1 and N2, have shown beneficial effects on yield parameters, enhancing overall plant growth, improving crop quality, and increasing yield-quality parameters.These fertilizers ensure that nitrogen is immediately accessible to plants and generate a notable "stay-green" effect, prolonging the functional lifespan of chloroplasts.Lastly, the use of controlled-release nitrogen fertilizers like Sulfammo 25 and Sulfammo 30 also contributes substantially to improved plant growth and crop quality.These fertilizers gradually release nitrogen throughout the vegetation period, increasing nitrogen utilization efficiency and further extending the chloroplasts' lifespan through the "stay-green" effect.