Improvement of methods and technical means of water erosion control during cultivating potatoes on a profiled field surface

BACKGROUND: Potato is a crop that requires the preparation of a fine-grained structure of the upper tuber-inhabited soil layer to form tubers of the correct shape, as well as to ensure conditions for good soil separation during harvesting. For this purpose, most technologies for cultivating this crop consider for the formation of a profiled field surface. One of the results of global climate changes is an increase in the frequency of heavy rainfall during the growing season. At the same time, the presence of a profiled surface on fields with even a slight slope leads to significant risks of water erosion during heavy rains due to water flowing from the ridge walls into the row spacing. This leads to annual irreparable losses of the fertile soil layer. Therefore, in order to ensure the preservation of the level of natural soil fertility and to eliminate the risks of water erosion when using intensive potato production technologies in the context of global climate changes, it is necessary to improve the technological methods and technical means used to form a profiled field surface.

OBJECTIVE: Protection of soil from water erosion during potato cultivation on a profiled field surface by improving technological methods and technical means used to form a profiled field surface, as well as justification of the parameters and modes of their operation.

METHODS: The study object is a non-powered rotary hole-digger mounted on an inter-row cultivator-subsoiler. To select reasonable parameters of working bodies of the hole-digger, theoretical studies were con-ducted on the basis of which the rotor diameter of its vanes was selected. The following assumptions were adopted as initial data for determining the technological parameters of the hole-digger: intensity of downpour; depth of the loosening tines of the row-crop cultivator-subsoiler; the rate of rain absorption by capillaries on medium-loamy soils at a certain degree of field slope. The theoretical calculation of the technological parameters of the hole-digger was performed on the basis of the built paths of the rotor center and its vanes during the working process. The calculation of the parameters of the hole-digger was carried out taking into account that the front and rear walls of a hole are formed by its vane by pushing loose soil during rolling with a step t relative to a fixed point at a certain depth h, the step of the hole-digger’s vanes t is determined by the design parameters of the rotor: diameter D and the number of vanes on it.

RESULTS: In order to determine the number of holes per linear meter, the volume of water that gets between the rows during a downpour was calculated depending on their inter-row width. The calculation results showed that with a precipitation intensity of 15 mm/h the number of holes per linear meter of the profiled surface of the field varies from 2.4 to 3.1 pcs/m. These data made it possible to deter-mine the reasonable parameters of the hole-digger for protection against water erosion of the fields located on slopes when cultivating potatoes on the profiled surface.

CONCLUSIONS: An effective method for preventing water erosion on the profiled surface of a field when cultivating potatoes is deep loosening between rows with simultaneous formation of holes at the bottom of the furrow. For this purpose, it is proposed to use a non-powered rotary hole-digger. When using a hole-digger with a rotor diameter of 600 mm the number of holes per linear meter varies from 2.4 pcs/m with a inter row spacing of 70 cm to 3.1 pcs/m with a inter row spacing of 90 cm. For reliable protection of soil from water erosion, it is enough to install 4 vanes on the rotor with the inter-row spacing of 70 cm, 5 vanes with the inter-row spacing of 75 and 80 cm, and 6 vanes will be required with the inter-row spacing of 90 cm.