Methodological and practical aspects of seed production of annual white sweet clover (Мelilotus albus Medik.)

Abstract

The purpose of the article is to analyze research results of the development and improvement of technology elements for growing white sweet clover in the conditions of southern Ukraine and to determine the optimal parameters of agricultural technology to ensure maximum seed productivity of the crop in irrigated and non-irrigated conditions. Research methods and materials. Field, visual, mathematical-statistical, and computational-comparative methods were used. Results. The use of optimal agrotechnical parameters contributed to the formation of high yields of annual white sweet clover seeds. The maximum seed productivity (789.0 kg), on average for 2015–2017, and the highest yield of conditioned seeds (88.8–89.9 %) were obtained when sowing in the first decade of April by a seeding rate of 2.5 million pcs./ha. The use and increase to 1.0 l/ha of the Pulsar 40 herbicide application rate in the of planting protection system of white sweet clover plants of the Pivdennyi variety led to an increase in the yield of conditioned seeds up to 1016.9 kg/ha. On average, during the 2016–2018 research period, the maximum seed yield (556 kg/ha) was obtained by sowing annual white sweet clover of the Pivdennyi variety using a row spacing of 45 cm and applying nitrogen fertilizer at a dose of N60. Research in 2018–2020 established that optimal conditions for the growth and development of annual white sweet clover plants were created by plowing to a depth of 25–27 cm (factor A), when the average seed yield was 0.56 t/ha (LSD05A – 0.03 t/ha). The optimal conditions for the growth and development of annual white sweet clover plants were established under irrigation (factor A), when the average seed yield was 0.47 t/ha (LSD05A – 0.12 t/ha). According to factor B (seeding rate), the highest seed yield (0.42 t/ha) was obtained by a seeding rate of 1.5 million pcs./ha (LSD05B – 0.07 t/ha). The maximum average seed yield of the crop (0.50 t/ha) was established by irrigation and using a seeding rate of 1.5 million pcs./ha. Studies in 2021–2023 established that growing annual white sweet clover on soils that have undergone salinization contributes to positive changes in the agrochemical composition of elements and desalinization, which indicated by the content of absorbed Ca+2 from the sum of cations in all variants of the experiment. Optimal conditions for the growth and development of annual white sweet clover plants were created by irrigation (factor A), when the average seed yield was 0.47 t/ha (LSD05A – 0.12 t/ha). By factor B (seeding rate), the highest seed yield (0.42 t/ha) was obtained at a seeding rate of 1.5 million pcs./ha (NIP05B – 0.07 t/ha). The maximum average seed yield (0.50 t/ha) was obtained under irrigated conditions at a seeding rate of 1.5 million pcs./ha. Cultivation of annual white sweet clover made it possible to obtain the best indicators of economic efficiency and increase the profitability of the beekeeping industry by increasing the yield of honey from 1 ha, which was obtained with the use of irrigation and a seeding rate of 1.5 million pcs./ha, which ensured the maximum conditional net profit (38, 0 thousand UAH/ha) at the lowest cost price of 1 ton of crop seeds (18.7 thousand UAH/t) and the highest level profitability (238 %). Conclusions. The results of the research, obtained on the basis of field experiments, the layout and conduct of which were carried out according to the generally accepted methodology for conducting field studies in irrigated and non-irrigated conditions. The optimal parameters of the annual white sweet clover cultivation technology were determined, which allowed to significantly improve the economic results of crop cultivation (conditionally net profit, profitability and yield).