INVERSION OF SEEDS AND ITS EFFECT ON THE QUALITY OF SINGLE-GRAIN SOWING
The inversion of seeds occurs at single-grain sowing. In the process of falling into the furrow, bouncing and rolling along the furrow the seeding sequence can be disturbed, i. e. negative intervals appear. This phenomenon indicates poor quality of sowing, and comes around due to the imperfections in the design of the sowing apparatus and in the process of covering seeds with soil, as well as due to heavy seed application rate. To assess the accuracy of the distribution of seeds along the furrow, the coefficient of variation of the intervals between them is used, but it is rather inconvenient, because it depends on the seeding rate and therethrough gives an incorret assessment of the advantages of the drill. By applying mathematical modeling of the single-grain sowing process a direct indicator of the drill efficiency was determined. This is a standard deviation of each seed from its calculated anchoring position in the furrow. This indicator does not vary according to the seeding rate, in case if the latter is regulated by seeding plates with different number of cells. Knowing its numerical value and seeding rate, it is possible to determine all numerical characteristics of such random variable as the interval between seeds, approximate the density of probability distribution of this value by gamma distribution law, and determine the possibility of inversion occurance and negative intervals emerging. Inversion partially equalizes the intervals, since from the plant development point of view negative intervals do not differ from positive ones, and only absolute value of the intervals is essential to the plantings. But inversion cannot improve accuracy of seeding up to the law of the normal density of intervals distribution. For this it is necessary to limit the seed application rate. When sowing sugar beet seeds without inversion with a norm of 7 pcs/m, technical means should ensure seeding accuracy corresponding to the standard deviation of each seed not more than 5 cm.