NARROW-LEAVEDLUPINE VARIETIES DEVELOPED BY THE LENINGRAD RESEARCH INSTITUTE OF AGRICULTURE AS AN EFFECTIVE GREEN MANURE CROP

Conservation and rational use of natural resources along with the need to increase agricultural productivity are included in the list of priority technologies approved by Decree of the President of the Russian Federation No. 529 of June 6, 2024. Green manuring is an effective and safe method for the soil that allows restoring and preserving soil fertility. Under the conditions of the north-east of the Non-Chernozem zone of Russia in 2022 and 2023, narrow-leaved lupine varieties developed by the Leningrad Research Institute of Agriculture were evaluated regarding some characters determining their suitability for green manuring. Generally accepted methods were used to establish the experiment and conduct research. It was found that on average over the years and compared to the control, the varieties Flamingo, Akkord and Metsenat produced a reliable level of herbage yield gain on absolutely dry basis. Their yields amounted to 16.755, 16.385 and 15.985 t ha on absolutely dry basis, respectively. The analysis of the fresh yield formula carried out during the period of maximum nutrient accumulation showed that lupine leaves and stems predominated in the total percentage. The leaf weight of the studied varieties exceeded the control more than 1.9 times. There were no significant differences in yield formula elements between the lupine varieties. The herbage of the varieties under study contained more crude protein than the control, and nitrogen collection per unit area was on average by 38% higher than that of the control. The maximum value was found in the varieties Flamingo (0.486 t ha) and Metsenat (0.436 t ha), both on absolutely dry basis. The ash content of most varieties was quite stable (V = 1.9-6.2%). The highest ash content was found in the variety Akkord (1.324 t ha on absolutely dry basis) which was by 64% more than in the control. The conducted studies indicate that under these soil and climatic conditions, narrow-leaved lupine varieties developed by the Leningrad Research Institute of Agriculture (Akkord, Metsenat and Flamingo) have a high degree of suitability for their use within the framework of measures contributing to the preservation and subsequent restoration of sod-podzolic soil fertility.