Features of irrigation and fertigation when growing tomatoes in spring greenhouses on the lower Don

The negative situation with irrigation water on the lower Don (high mineralization level, high pH level and dangerous substances content) covers all zones of commercial cultivation of vegetable crops in protected ground, located near industrial centers. The transition to drip irrigation systems when growing tomatoes in spring greenhouses has changed the structure of water consumption and reduced the amount of water consumed. The use of drip irrigation when using mineralized water complicates fertigation. To meet the needs of tomato plants in water and nutrients, an important place is occupied by the system of placing drip lines. The main purpose of the research was to establish the optimal layout of drip lines when growing tomatoes in spring greenhouses and the features of the use of fertilizers in drip irrigation. The research was carried out in 2019–2022 at the Rostovsky Breeding and Seed Center of the Poisk Agricultural Company, located in the Oktyabrsky District of the Rostov Region. The climate of the zone is hot, arid with a long frost-free period. Weather conditions during the years of the study were characterized by sudden changes in temperature in the spring and high temperatures with a lack of precipitation and low relative humidity in the summer. The soils in the experiments are represented by ordinary chernozem. Irrigation was carried out from the Grushevka River, which belongs to the basin of the lower reaches of the Don River, and from underground sources. The fertilizer system included the main application for milling at a dose of N₁₂₀P₁₂₀K₁₂₀ from autumn and the application of fertilizing during the growing season at a dose of N₆₀P₆₀K₆₀ + micro fertilizers through the fertigation system and on the leaves. The objects of research were hybrids of tomato F₁ Donskoy and F₁ Armada. The experiments were laid in spring unheated greenhouses with a polycarbonate translucent coating. As a result of the research, it was found that the most optimal is the placement of 2 drip lines with a distance of 10 cm from the center of the row on both sides. At the same time, a higher level of yield was obtained due to an increase in the number of marketable fruits and their average weight. When fertigation is used, a positive effect on the growth and filling of fruits has been confirmed by the use of only fertilizing irrigation with weakly concentrated fertilizers while maintaining their total dose and using foliar dressings.

Key words: spring greenhouses, irrigation water, drip irrigation, fertilizer, tomato.