Seasonal dynamics of agrichernozem properties in cultivation of spring rape on oil seeds

In a field experiment under the conditions of the Krasnoyarsk forest-steppe, the assessment of the seasonal dynamics of the agrophysical and agrochemical properties of agrochernozem during the cultivation of spring rape variety Nadezhny 92 for oilseeds was carried out. Studies have established that the functioning of spring rapeseed in arid conditions was characterized by poor reserves of productive moisture with high seasonal variability (Cv = 59 %), loose constitution (0,93 g/cm3) and excellent structure (75 %) 0-20 cm layer of agrochernozem (Cv = 14-16 %). It is shown that dynamic changes in agrochemical parameters by 51-96 % are associated with soil moisture conditions. The replenishment of the easily hydrolyzable nitrogen fund during the flowering period of rape due to the death of roots and parts of the aboveground mass was accompanied by its transition to the mineral form (r = -0,76), which affected the seasonal dynamics of mineral forms of nitrogen (Cv = 43-55 %). An increase in the supply of ammonium nitrogen to a very high one by the period of seed ripening (26 mg/kg) indicated its accumulation in the soil and was accompanied by the predominant consumption of nitrate nitrogen (6 mg/kg). The time-stable indicators were the reaction of the soil solution (Cv = 1 %), the content of mobile phosphorus and exchangeable potassium (Cv = 19-17 %). Against the background of an average (131 mg/kg) and very high supply (209 mg/kg) of agrochernozem with mobile phosphorus and exchangeable potassium, their accumulation in the soil solution was noted in the period from flowering to the ripening of rape seeds, which indicates the agromeliorative effect of the culture on the soil and her fertility.