TY JOUR TI ECONOMIC EFFICIENCY OF USING THE KUBAN-LK1 CIRCULAR SPRINKLER WITH AN IMPROVED RUNNING SYSTEM KW Kuban-LK1 sprinkler KW multi-bearing running system KW track formation KW rolling resistance KW leveling device KW soil bearing capacity KW power balance KW economic efficiency KW irrigated agriculture JO MOSCOW ECONOMIC JOURNAL AU Ryazantsev, A.I. AU Evseev, E.Y. AU Travkin, V.S. AU Travkina, A.R. PY 2026 IS 11 PB Electronic science