Patterns of Influence of Winter Wheat Sowing Density on Its Yield

Abstract

Introduction. The article deals with the soil morphological features and grain varietal characteristics as the main factors on which the dynamics of the winter wheat development from seedlings to full grain ripeness depends. Aim of the Article. The article is aimed at determining the main patterns of plant development depending on internal and external factors affecting the winter wheat yield. Materials and Methods. The winter wheat variety RS-1 “Tanyaˮ was an object of the research. Sowing was carried out in the production zones of the North Caucasus Federal District. The size of the area amounted to 70 ha; there were two experiments with different seeding rates. The reliability of the results was checked using Fisher's and Student's coefficient. There were carried out monitoring of the complete cycle of plant development - from seedlings to full grain ripeness. Results. The dynamics of changes in morphological parameters of plants germinated from seeds at seeding rates of 2.6 and 6.5 million pieces/ha was compared. The role of external and internal factors determining the dependence of wheat yield on seeding rate was analyzed. The external factors included the growth environment factors determining the health of plants and relating growth environment to the sowing density. At the same time, there were considered physico-chemical properties of soil including its fertility with capacity index (the amount of mineral substances and their fractional composition), the strength of the bond between mineral substances and the matrix soil, and the rate of transition of soil ions from the matrix soil to aqueous solution. When analyzing the soil prepared by the proposed cultivation technology, it was found that at a seeding rate of 6.5 million pieces/ha the number of productive stems was 550 pieces (0.0575 pieces/kg of stems), and at a seeding rate of 2.6 million pieces/ha their number was 575 pieces (0.183 pieces/kg of stems). Discussion and Conclusion. The influence of wheat seed sowing density on yield was evaluated using the Gardner equation and parameters of sorption properties of wheat root systems. It was shown that for wheat sowing density at seeding rates of 2.6 and 6.5 million pieces/ha the ratio between the values of diffusion coefficients D(6.5)/D(2.6), obtained taking into account the grown stems, was ~ 1.7 times. It was found that the determining factor is the soil structure, on which the parameters of water supply depend. The type of developing root system is determined by the water absorption rate and the depth to which water is extracted from the soil per plant. The factors determining the effect of seeding density on yield include osmotic parameters of seed cell membranes. Accumulation of proline as an osmotically active organic matter in the cell promotes water retention in the cell. The use of microelements and growth regulators for treating seeds germinated at sowing rates of 2.6 and 6.5 million pieces/ha leads to a greater increase in the proline concentration in the cytoplasm in the first case than in the second.