Optimal sowing density for pea varieties under moisture deficit conditions in Southern Ukraine

Abstract

Purpose. To determine the optimal sowing density for modern pea (Pisum sativum L.) cultivars under the stressful conditions of soil moisture deficit in Southern Ukraine and to evaluate cultivar differentiation based on adaptive traits. Methods. Field studies were conducted in 2025 on southern medium-humus chernozem during an arid growing season with a critical precipitation deficit (116 mm). The research objects were the pea cultivars Eso, Impuls, and Mikka. Three sowing density variants were investigated: 600, 800, and 1000 thousand seeds per hectare. The analysis focused on yield formation and the fresh and dry biomass weight of plants under different levels of crop stand density. Results. It was established that a general increase in sowing density led to a decrease in plant biomass weight across all cultivars. However, a clear cultivar-specific response to agrocenotic stress caused by the combination of drought and high stand density was revealed. The Mikka cultivar demonstrated the highest adaptive capacity and plasticity, maintaining stable biomass indicators even at the maximum density (1000 thou. seeds/ha), whereas the Eso and Impuls cultivars showed significantly greater sensitivity to the stress factors. Based on the obtained data, the optimal sowing density range ensuring a balance between plant population and the limited resource potential of the agrocenosis under drought conditions was determined to be 750–850 thousand seeds per hectare. Conclusions. To form stable and productive pea stands under climate change conditions in southern Ukraine, it is necessary to move away from universal recommendations regarding seeding rates. A key factor is the mandatory consideration of cultivar-specific features of adaptability and plasticity. The research results provide scientifically sound tools for developing differentiated agrotechnologies aimed at enhancing agroecosystem resilience, economic efficiency of production, and ensuring food security under conditions of a destabilized climate.