THE NUTRITION ELEMENTS CONTENT IN AGRICHERNOZEMS WHEN GROWING EARLY POTATO IN THE KRASNOYARSK FOREST-STEPPE

The purpose of research is to study the dynamics of the content of nutrients in agrochernozems during the cultivation of the ultra-early potato variety Kolomba in the Krasnoyarsk forest-steppe. The soil cover of the study area is represented by a complex of agrochernozems of clay-illuvial typical and agrochernozems of cryogenic-micellar, medium- and heavy-loam varieties. Soil preparation for planting included the application of azofoska at a dose of 60 kg AI/ha by a broadcast method, followed by its incorporation with a milling cutter. The predecessor is pure black fallow. The selection of mixed soil samples was carried out from the soil layer of 0–20 cm and 20–40 cm in 6 repetitions according to different variants and phases of potato development. The provision of the arable layer of agrochernozem with nitrate nitrogen during the growing season sharply decreased from very high (30.6–69.7 mg/kg) to medium and low (8.3–6.5 mg/kg), especially in variants with germinated tubers in budding and flowering phase. In the control variants, at the same time, there was a phase of stem growth and budding, and the supply of nitrate nitrogen remained at an increased level (13–14 mg/kg). The content of ammonium nitrogen in agrochernozems by the beginning of July also decreased to an average and low level of availability (7.2–8.3 mg/kg), at this time, the budding and flowering phase was noted on the variants with germinated tubers, and on the variants with unsprouted potato tubers - the phase of stem growth and budding. In all variants of the experiment, the availability of exchangeable potassium during the growing season dropped from a very high (155–162 mg/kg) to a high and elevated level (133–93 mg/kg), the availability of mobile phosphorus in the second half of the growing season also decreased from a high (170, 4 mg/kg) to an increased level (136.3 mg/kg) on variants with germinated tubers. The yield of sprouted potato tubers of the Colomba variety after 50 days of vegetation was 16.3 t/ha, which is two times higher than in the control.