In the dissertation the scientific problem which is directed on increase of accuracy of seeding and intensification of the beginning of vegetation of vegetable cultures by development of a design and a substantiation of constructive-technological parameters of the hydropneumatic device of exact seeding is solved
In the first section the analysis of ways of coordination of working bodies in system of exact agriculture and devices of exact sowing is carried out, taking into account their advantages and lacks the scheme of the hydropneumatic device of exact sowing of vegetable crops is developed.
In the second section the theoretical substantiation of constructive, technological and operational parameters of the hydropneumatic device of exact seeding is given. It is theoretically established that the formation of a fluidized bed in the intake chamber with a seed diameter of 1… 5 mm occurs while maintaining the upward flow rate within 0,02… 0,2 m / s, respectively, the cross section of the intake chamber in the upper part is 331 mm2 in the lower part 67 mm2. The height of existence of the fluidized bed is in the range of 56… 68 mm with the width of the intake chamber within 15..18 mm and the angle between the sides of the intake chamber 15º… 20 º.
A physical and mathematical model of the process of formation of a fluidized bed in the intake chamber has been developed, which allows to set the kinematic parameters of seed movement (vectors of displacement, velocity and acceleration). As a result of numerical simulation of the process of formation of the fluidized bed in the intake chamber, the dependence of the height of the seed tube h on the angle between its surfaces α and the initial velocity of the liquid vo is established. Taking into account the previously determined and accepted design and technological parameters of the intake chamber, the height of the seed line is within 0,022… 0,036 m
Numerical modeling of the technological process of loading seeds into the seed line allowed to obtain the value of the minimum allowable initial flow rate of liquid through the hydraulic valve vt (0,42-1,45 m/s), which guarantees reliable loading of seeds to the seed line of hydropneumatic precision seeding.
The third section presents the program and methods of experimental research aimed at further study of the technological process of formation of the fluidized bed in the intake chamber, subsequent charging of seeds and its distribution through the seed line, the impact of the main components of the hydropneumatic apparatus . For this purpose, a laboratory installation of a hydropneumatic precision seeding apparatus and an experimental drill have been developed.
According to the results of the research in the fourth section it is established that the seeds of vegetable crops have different hydrodynamic properties (sail, humidity). The hydroseparation allowed to divide the seeds into groups with the same hydrodynamic properties and to separate the germinated seeds. According to the results of laboratory studies, the germination of germinated cabbage seeds was 100%, tomato 100%, pepper 98%, which exceeded the dry method of sowing cabbage by 12,3%, tomato 16,7%, pepper by 19,2%. As a result of soaking the dry seeds of vegetable crops, the volume increases in the range of 1,45… 1,96, which is taken into account when choosing the size of the tank. The porosity of the layer is almost independent of seed swelling and is in the range of ε = 0,39… 0,41.
According to the results of the study of the process of formation of the fluidized bed in the collection chamber, it was found that to ensure reliable operation of the sowing machine, the seed concentration should be within kн = 0,21… 0,65 1/ml. Use of the regulator of a expense of the circulating pump allows to provide maintenance of the set value of concentration of seeds irrespective of level of filling by it of a tank.
According to the results of a multifactorial experiment, rational values of technological parameters of the hydropneumatic apparatus of precision seeding were established: seeding frequency fв = 4,8 Hz, supercharging pressure Pнад = 0,348 MPa, seed concentration kн = 0,45 1/ml at which the highest value of seeding accuracy was obtained 95,1 %.
The hydropneumatic device of exact seeding of the germinated seeds of vegetable cultures established on a frame of the basic Klen-1,8 seeder passed production test. Field studies have shown that the rational design and technological parameters of the coefficient of variation of plant distribution in the row on the tomato crop "Asteroid" decreased by 10,6% compared to the base seeder Klen -1,8 and amounted to 23,6%. As a result, the seed germination increased to 93% and the tomato yield increased by 66 c/ha. The economic effect from the use of a seeder with a developed hydropneumatic device for precision seeding on tomato sowing "Asteroid" amounted to 11,3 thousand UAH/ha.
