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Aim. Determination of phytocenosis productivity, nitrogen concentration and reserves in blocks of plant associations and by soil types in the North‐Western Precaspian region of Russia. Methods. Comprehensive research on the accumulation of organic matter and nitrogen in five blocks of plant matter, six plant associations and three types of soil by season using well‐known methods of accounting and analysis of soils and plants. Results. The regularities of phytomass formation, changes in nitrogen concentration and reserves in the main soil types and six plant associations for the 2011–2018 seasons were revealed. Conclusions. Ephemeroid‐wormwood‐cereal, ephemeroid‐wormwood, cereal‐wormwood, forb‐campfire and mixed‐grass‐campfire plant communities formed on light chestnut soil are the most productive, with a total productivity of 24.34 t/ha. The maximum nitrogen concentration was observed in the cereal‐wormwood, wormwood‐saltwort, forb‐saltwort and cereal‐saltwort associations – 1.9, 1.97, 2.2, and 2.57%, respectively, which is due to the predominance of Artemisia taurica Willd., Artemisia lercheana Web.ex Stechm. and Salsola iberica Sennen&Pau. In associations where there are representatives of the Poaceae, Brassicaceae and Caryophyllaceae, nitrogen decreases to 1.72–1.74%. Its value was higher on light‐chestnut soil, being 1.82% of absolutely dry mass, while on meadow‐chestnut soil it decreased to 1.75 and on saline soil is typically 1.38%. In the root mass of plant associations, its indicators were 3.2 times less than in the above ground mass. Nitrogen reserves by blocks of plant matter formed the following decreasing series: roots ≥ green mass ≥ rags ≥ felt. In the input part of the balance in plant associations, 171.6 nitrogen accumulates on light‐chestnut soil, 63.1 on meadow‐chestnut soil, 49.1 kg/ha on automorphic typical saline soil, and 171.9; 64.3 and 58.1 kg/ha in the expenditure part, respectively. the balance of nitrogen in the first type of soil is formed with a minimum deficit of 0.6 kg/ha, 1.2 and 9 kg/ha, respectively.

Evaluation of productivity of arrays of Thymus serpyllum L. in various phytocenoses in East Transbaikalia, conducted by the method of work in key areas, showed that the highest crop capacity of its raw materials accounted for the steppes and depends primarily on the species’s projective cover of the occupied areas. The total area of the identified the jungle is 34006 hectares, the production area is 2210 ha. The determined biological reserve in the investigated area is 841,58 tons, the possible annual harvesting volume is 306,49 tons. The research allowsto attribute this speciesas perspective for harvesting.

The processes limiting the production in higher plant phytocenoses under an artificial-light culture are analyzed in relation to the multilevel organization of the photosynthetic apparatus (PA). The authors consider the feasibility of overcoming these limitations by optimizing the physical parameters of irradiation (the structure of the light spectrum, the rate, and the ratio of radiation fluxes in photosynthetically active radiation (PAR) and infrared (IR) regions) at the molecular, leaf, plant, and cenotic levels of PA organization. To illustrate this approach, the authors used a complex experiment in an artificial ecosystem to evaluate the efficiency of the light control of production processes in multispecies phytocenoses by alleviating or removing the factors that limit plant production at the various levels of PA organization. An artificial-light culture is seen as an instrument for solving several problems of theoretical and applied plant physiology and related disciplines in the future. [ABSTRACT FROM AUTHOR]