Field experiments were carried out on chestnut soils of Piedmont Dagestan in 2018-2020. Hybrids of grain corn treated with different growth stimulants were the object of еру research. The experiments showed that the harvesting ripeness of hybrids ROSS 299 MV and Mashuk 355 MV occurred 2...5 days earlier after treatment with growth stimulants compared to the control. The growth stimulants used in the experiment did not have a significant effect on seed germination rate. Among the studied hybrids, the highest seed germination were observed in Mashuk 355 MV hybrid. The highest values of leaf area and net productivity of crops were in hybrid Mashuk 355 MB. Plants treated with growth regulators had higher leaf surface by 4.4% and 5.5%; 6.0 % and 8.4%, respectively. Approximately the same dynamics was recorded for photosynthesis net productivity and accumulation of dry matter. Mashuk 355 MV hybrid showed the best yield, which was 30.5; 31.5 and 32.5% higher respectively, compared to the standard. Productivity of corn hybrids treated with growth regulators increased significantly. The highest data were observed on plants treated with Megamiks N10 growth regulator, which were higher than the control data by 30.0 and 32.5%, respectively. Aminokat 30% growth regulator increased corn productivity by 23.7 and 24.7%, respectively. Sufficiently high indicators of yield structure were 10 recorded in Mashuk 355 MV hybrid in the variant with the Megamiks N10 growth stimulator.

Productivity of the natural phytocenosis and maize for silage in stubble sowings under two ways of the biomass yield usage in Kirov FSSU in Khasavyurtovskiy district in the crop rotation link “winter wheat+stubble crops+maize for grain” are studied. The soil is light-brown heavy clay loam. It was found that during stubble period after winter wheat harvesting it can be obtained 21.9 t/ha of the natural phytocenosis herbage and 33.0 t/ha maize for grain. However, cultivation of the stubble corn is associated with additional financial and material-and-technical outgoings. Plowing under of the herbage and application of fertilizers and winter wheat straw without tillage operations during nature phytocenosis yield formation contributes to improving of the soil fertility indicators. The number of agronomically the most valuable structure aggregates in the topsoil layout are increasing to 63%, soil porosity- to 54.2%, soil density is reduced to 1.20 g/ cm3, soil nutritive regime is improving. The soil fertility indicators optimization allows to increase yield of next corn in crop rotation with a phytomass plowing under to 36.2, stubble corn- to 46.0 %

The data of the researches describes the were to establish the species composition of pasture cenoses and the productivity potential of light-chestnut and meadow-chestnut soils under different climatic conditions and in different periods of the year in the Terek-Kuma lowland of the North-Western Precaspian. Two peaks of productivity of phytocoenosis have been observed: the first is – ephemeral synusia in the middle of May- early June; second – motley grass and saltworts in the second half of September. The data on receipt of photosynthetically active radiation (PAR) on the soil surface and the coefficient of its use over the years and periods of the year depending on the hydrothermal conditions and dynamics of harmful salts in the soil are given. On light-chestnut soil formed cereals-wormwood, grass-cereals, wormwood-ephemeral in combination with wormwood-saltworts association, and meadow-chestnut soil – ephemera-wormwood. The phytocenosis on light-chestnut soil is inherent in the maximum species diversity – 35 species. On meadow-chestnut soil there are only 25 species. The items of the changes in the species composition of phytocenoses depending on the environmental factors are considered. The data in this article support and augment information presented in the research articles [1] , [2] , [3] , [4] , [5] , [6] , [7] .

The data on receipt of photo synthetically active radiation (FAR) on the soil surface and the coefficient of its use over the years and periods of the year depending on the hydrothermal conditions and dynamics of harmful salts in the soil are given. The items of the changes in the species composition of phytocenoses depending on the environmental factors are considered.

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