Potential of productive longevity of legum-mint grass mixture in the south of Western Siberia

Perennial legume-bluegrass herbaceous stands stabilize forage production for highly productive livestock farming and make a significant contribution to the nitrogen balance of agroecosystems in Western Siberia. The studies were conducted to study the effect of mineral nutrition conditions on the growth, development and dry matter yield of a mixture of goat’s rue and brome grass in the forest-steppe of Western Siberia. The work was carried out in 2000…2021 in a stationary field experiment on meadow-chernozem medium-deep medium-humus heavy loamy soil in the Omsk region. The experiment was laid out in the hatchery field of the 8-field crop rotation (eastern galega, eastern galega + brome, spring barley, field pea, sweet sorghum, alfalfa + brome, forage beans, millet + rapeseed) according to the scheme providing for the study of the following options: potassium fertilizer (factor A) – K₀, K₆₀; nitrogen fertilizer (factor B) – N₀, N₃₀, N₆₀; soil supply with mobile phosphorus (factor C) – average (70…80 mg/kg according to F. V. Chirikov, background 0), increased (background I – 120, background II – 140 mg/kg), high (150…160 mg/kg, background III). The most balanced ratio of legume and bluegrass components was on the backgrounds with increased and high content of mobile phosphorus in the soil. Without the application of nitrogen fertilizers against these backgrounds, the competitive ability of goat’s rue increases, which is ecologically and economically effective. Against the background of irrigation, the yield of the grass mixture reaches 8 … 9 t/ha of dry mass in variants with a sufficient level of phosphorus (increased and high content) at 6.35 t/ha without fertilizers. In subsequent years, in the absence of irrigation, the picture changed towards a general decrease in yield to 5 … 6 t/ha of dry mass in fertilized variants at 3.60 … 4.81 t/ha in the variant without fertilizers. In the second decade, a reliable manifestation of yield growth in variants without nitrogen fertilizers is by 0.49 in 2011 … 2015 and by 0.99 t/ha in 2016 … 2021 on average by factor, due to an increase in the share of goat’s rue in the botanical composition.