Formation of the agrocenosis of alfalfa changeable Daria in cover crops in the conditions of the forest-steppe of the Middle Volga region

The research was carried at the experimental field Federal Research Center for Bast Fiber Crops – Separate division "Penza Research Institute of Agriculture". The scientific novelty of the research consists in determining the best cover crops, the influence of their seeding rates on the formation of the agrocenosis of alfalfa changeable Daria in the conditions of the forest-steppe of the Middle Volga region. The purpose of the research is to develop elements of the technology of alfalfa of the variable Darya variety for feed, based on the selection of cover crops and their seeding rates, providing optimal conditions for the formation of herbage in the conditions of the forest-steppe of the Middle Volga region. The purpose of the research is to develop elements of the technology of alfalfa of the variable Darya variety for feed, based on the selection of cover crops and their seeding rates, providing optimal conditions for the formation of herbage in the conditions of the forest-steppe of the Middle Volga region. The objectives of the research included: to study the features of the formation of the agrocenosis of alfalfa variable in subcover and non-cover crops; to select cover crops and their seeding rates that contribute to the optimal development of the density of alfalfa variable herbage. The research was carried out in field crop rotation in a two-factor field experiment in 2 bookmarks in 2020-2021, the most optimal cultivation techniques were identified: cover crops. In the variants of the experiment with oilseed flax and barley at 60% seeding rate, plant safety was at the level with the control – 74 and 71 pcs/m2 (from -2.6 to -6.6%). In the 1st year of life, on average, according to seeding standards in subcover crops, there is a significant decrease in the safety of alfalfa (from -19.3 to -36.1% of the control). For 2 years, the winter hardiness of plants increases significantly with a decrease in the seeding rate to 80% in variants with Abyssinian crambe, white mustard and oilseed flax (from +8.1 to +8.8%) compared with 100% seeding rate. With a decrease in the seeding rate to 60%, a significant increase in the safety of alfalfa plants was noted for all cover crops (+9.3%). By the end of the growing season of 2 and 3 years of alfalfa life, the safety and winter hardiness of plants according to the studied factors does not change significantly and remains at the level with the control variant.