Green manuring in the Kuban

The main reason for the increase in soil fertility of the Krasnodar region is the provision of soil with organic matter, based on reaching a deficit-free balance of humus and its further expanded reproduction. The observance of crop rotation has a special role in solving this problem in accordance with the law of the Krasnodar region of April 30, 2020 № 4286-KZ “On amending Article 71 of the Law of the Krasnodar region”. At least 10 % of the total arable land should be sown with perennial legume grasses and legume crops. For land plots with an area of up to 100 hectares, these measures are allowed to be replaced by embedding in the soil of crushed post-harvest residues of agricultural crops (except for those necessary for the needs of livestock breeding) with the addition of 5 kg of nitrogen per ton. It is also indicated that it is necessary to apply organic fertilizers (bedding manure) in the amount of at least 9 tons per hectare of arable land once every five years over the entire area. In case of a lack of organic fertilizers, it is allowed to replace such top dressing by sowing green manure crops on an area of at least 20 % of the total arable land.

Green manuring is the plowing of the green mass of plants (green fertilizer) into the soil to enrich it with nitrogen and organic matter.

Oil cole crops (winter and spring rapeseed; white, brown, and winter mustard; winter turnip rapeseed) meet the requirements for green fertilizers to the greatest extent. They are characterized by a fast growth rate of vegetative mass and a good development of the plant root system. These crops have a wide growing area; for green manure, they can be used as both an independent and intermediate crop.

In terms of efficiency, burying of plant residues of cole crops is comparable to the introduction of semi-rotted bedding manure of cattle, and the utilization coefficient of nitrogen in green manure in the first year is almost twice as high as that of manure nitrogen. At the same, time the cultivation of green manure crops is significantly cheaper since it does not require transportation and spreading over the field.

Green manure oil cole crops of VNIIMK breeding are annual plants valued for their ability to grow quickly and have a large green mass (Table).

Table. Productivity of green mass at the stage of budding – the beginning of flowering of varieties of oil cole crops of VNIIMK breeding.

Crop                            Variety           Productivity, t/ha                         Moisture content, %

Due to the deep and branched root system, coil crops loosen and structure the soil, improve its agrophysical properties, prevent soil erosion and development of weeds. The root secretions of some soil crops and the substances formed during the decomposition of their plant residues have a certain phytomeliorative effect, suppressing soil fungal infection and the development of soil-dwelling pests. With the decomposition of the green mass of green manures in the soil, the number of oligonitrophilic microorganisms increases, which contributes to an increase in the fixation of atmospheric nitrogen.