EFFICIENCY OF LOCAL APPLICATION OF PHOSPHORUS-POTASSIUM FERTILIZERS IN POTATO CULTIVATION

Abstract

Purpose. The purpose of the conducted research was to comprehensively study the effectiveness of using macronutrients under different technologies of their spatial distribution (broadcast and band) and different rates of mineral agrochemicals application. The main task was to reliably establish their direct impact on the level of overall productivity and the yield of the target seed fraction of tubers. In addition, the study aimed to determine the optimal spatial architecture of nutrition, which would minimize the negative impact of abiotic stresses (in particular, moisture deficit in the upper soil layers) and significantly reduce the chemical binding of nutrients by the soil absorbing complex. This is fundamentally important for optimizing modern agricultural production and ensuring yield stability. Methods. To achieve the set objectives, a large-scale field experiment was implemented on the production areas of Biotech LTD LLC (Boryspil district of Kyiv region) on dark gray podzolized soil. The research was conducted on plantings of the early-maturing variety "Tyras". The experimental design was based on comparing the traditional (continuous broadcasting) and innovative band (in the zone of the main root system mass) placement of nutrients. The basic nutritional background for all plots without exception was nitrogen at a rate of 150 kg/ha of active ingredient. The control variant involved the continuous distribution of the full rate of macronutrients (P80K180). The experimental variants included band placement of the full rate, as well as rates reduced by 25% (P60K135) and 50% (P40K90). The technological operation was carried out by specialized units with injectors to a depth of 15–20 cm. Harvesting was carried out mechanistically with subsequent detailed fractional analysis (separation of standard seed specimens of 28–55 mm and non-standard ones). The statistical reliability of the obtained data arrays was evaluated using one-way analysis of variance (ANOVA) applying the Tukey test (HSD) at α = 0.05. Results. Experimental data objectively prove that the spatial localization of nutrients has a decisive influence on the productivity of the plant organism. In the control variant with the continuous distribution of the full rate, the gross harvest was 29.3 t/ha, while the mass of the standard seed fraction was 23.3 t/ha (79.5% of the gross), and the volume of non-standard tubers reached 6.01 t/ha. The transition to the band placement of a similar full rate provided an increase in the gross harvest to 31.5 t/ha, and the yield of the target fraction to 28.3 t/ha. The highest agronomic performance was demonstrated by the variant with spatial optimization and a 25% reduction in the rate (P60K135). Under these conditions, an absolute maximum gross mass was recorded at the level of 34.2 t/ha. This approach provided the best marketable structure: the mass of high-quality seed material reached 31.0 t/ha (90.6% of the total gross harvest), while the volume of non-standard specimens was minimized to 3.17 t/ha. A radical 50% reduction in the rate with band application (gross harvest 30.9 t/ha) also proved to be more effective than the traditional approach, confirming the physiological advantage of the spatial proximity of elements to the root system over their total physical mass. Findings. The conducted studies convincingly demonstrated the high efficiency of spatial optimization of mineral nutrition systems. It is proved that the band placement of agrochemicals directly into the zone of active root system development stabilizes the assimilation of compounds under moisture deficit conditions and minimizes their transition into inaccessible forms. The most economically and agronomically justified is the use of band technology with an optimized macronutrient rate reduced by 25%. Such an approach guarantees not only obtaining the maximum gross harvest but also the formation of a flawless crop structure with the highest percentage of high-quality seed material. The wide implementation of such innovative solutions in production is a strategically important tool for unlocking the genetic potential of plants.