Nitrogen Feeding of Winter Peas at the Spring Vegetation Re-Covery Stage

Abstract

In a field experiment from 2020–2023 on the southern chernozems of the Odessa region of Ukraine, we studied the effect of the doses and timing of mineral nitrogen application when growing winter peas on the tuberization process and crop productivity. Mineral nitrogen in doses of 30, 45 and 60 kg/ha in the form of ammonium nitrate was applied in different development phases of winter peas under seedbed cultivation: foliar top dressing with urea solutions during the resumption of spring vegetation, the budding phase and the beginning of grain filling. Winter pea of the Enduro variety was sown annually on October 20, with a row spacing of 15 cm and a rate of 1.2 million germinating seeds per hectare. The previous crop was winter wheat. The conditions of the Southern Steppe of Ukraine for winter sown peas were shown for the first time. The introduction of mineral nitrogen at a rate of 30–60 kg/ha into the soil during sowing inhibited the formation of nodules from the active spring growth phase. The mass of nodules on the roots of pea plants decreased by 30–50% compared to the control variant without nitrogen application. The same norms of mineral nitrogen introduced in early spring during the resumption of vegetation on the leaf in the form of aqueous solutions did not have a negative impact on tuberization. The correlation coefficient between the dose of mineral nitrogen and the number and weight of nodules did not exceed 0.37, indicating a weak relationship between these indicators. The share of influence of mineral nitrogen norms did not exceed 13.7%. With this method of application, the nitrogen content in the vegetative mass of winter peas exceeded the control variant by 18–27%.