Evaluation Of Nitrogen Yield-Forming Efficiency In The Cultivation Of Maize (Zea Mays L.) Under Different Nutrient Management Systems

Failure to adjust the fertilization system to quantitative needs, and especially to the dynamics of mineral demand, causes plant metabolism disorders, low mineral utilization by the plant, and an increased risk of environmental pollution. Additionally, unbalanced mineral fertilization may reduce the assimilation surface actively involved in photosynthesis, which determines the yield potential of individual varieties. The aim of the strict field experiment was to determine the responses of two types of maize varieties (Zea mays L.) to treatments with different nutrient management systems, as expressed by the growth analysis of active organs during photosynthesis, SPAD (soil and plant analysis development) leaf greenness index, green mass yield, and unit nitrogen productivity from PFPFN mineral fertilization (partial factor productivity fertilizer nitrogen). It was demonstrated that the total area of leaf blades of a single plant and the LAI (leaf area index) value were significantly higher in the "stay-green " hybrid compared to the traditional variety. The analysis of leaf morphological structure of the "stay-green " hybrid, based on SLA (specific leaf area), indicated a highly effective utilization of nitrogen, leading to faster leaf production with a larger assimilation area, which formed the basis for effective absorption of solar radiation. The selection of "stay-green " varieties for silage cultivation guarantees high green mass yields. The risk of lower maize biomass intended for ensilage can only be reduced by applying balanced mineral fertilization of all nutrients. The omission of phosphorus (P) and potassium (K) in the mineral fertilization dose, regardless of the variety tested, was a factor reducing the yield of maize biomass intended for ensilage and a lower partial factor productivity of nitrogen fertilizer compared to the treatment optimally balanced with respect to the nitrogen dose.