Potato haulm pre-harvest removal effect on tuber maturation

The purpose of the study is to establish the optimal timing and methods of pre-harvest removal of tops from a new potato variety, ensuring the reduction of mechanical damage to tubers and increasing their safety. The experiments were carried out in 2015-2017 in the climatic conditions of the Primorsky Region. The soil of the experimental plot is bleached meadow-brown. The scheme of the experiment included the following variants: control - mechanical removal of the vegetative mass was carried out on the day of harvesting; option 1 - the destruction of the vegetative mass by mechanical means 10 days before harvesting; option 2 - removal of tops by chemical method using desiccant Reglon, BP, 10 days before harvesting; option 3 - removal of the above-ground biomass of potato plants by mechanical means 20 days before harvesting; option 4 - removal of tops Reglonom, BP, 20 days before harvesting. The methodology of the experiment and the technology of potato cultivation are generally accepted for the Primorsky Region. When processing the tops of potatoes with Reglon 20 days before harvesting, the lowest values of the pulling force were observed - 19.3 N and the connection of tubers with the bush - 26.9 %, in the control - 35.8 N and 56.1 %, respectively. The cutting and desiccation of tops 20 days prior to harvesting significantly reduced the force of separation of potato tubers from stolons (6.1 and 6.2 N) and rupture of stolons (12.5 and 12.1 N), in contrast to the control - 8.7 and 14 .9 N. In the variants with the removal of potato tops 10 and 20 days before harvesting, the gross yield is lower (29.3-33.0 t/ha) than when the vegetative mass is mowed on the day of harvesting (35.0 t/ha). Removing the vegetative mass of potatoes by mechanical means 10 and 20 days before harvesting reduced the yield of standard seed material to 18.0 and 17.6 t/ha, respectively, in contrast to desiccation (19.1 and 19.4 t/ha) and mowing per day harvesting (19.2 t/ha).