Agrochemical state of the Chulym-Yenisei forest-steppe chernozem during fallow lands development for organic farming purposes

The purpose of the study is to assess the agrochemical state of leached chernozem in the Chulym-Yenisei forest-steppe under conditions of transition to organic farming. Research was carried out in the land use of KH Rodnik LLC in the Balakhta District, located in the Chulym-Yenisei forest-steppe of the Krasnoyarsk Region. In crops cultivated using a fallow predecessor against an intensive background and cultivated 27-year-old turf fallow, an assessment was made of the reaction of the soil solution, the provision of the 0-20 cm soil layer with mineral nitrogen, mobile phosphorus and exchangeable potassium. It has been shown that the reaction of the soil solution of chernozem in crops cultivated in crop rotation according to an intensive background is on average assessed as neutral (6.9-7.3 pH units). In the treated fallow, there was a significant decrease in pH2o to a slightly acidic reaction of the soil solution (6.3-6.5 pH units). The functioning of the 27-year-old turf fallow and its redevelopment determined a significant change in the supply of chernozem with ammonium, nitrate nitrogen and mobile phosphorus. In the crops of two wheats cultivated under intensive conditions, chernozem was assessed as having medium and low levels of ammonium and nitrate nitrogen (2-10 mg/kg). The treated fallow formed a high and medium supply of ammonia nitrogen (8-17 mg/kg), a very high and increased supply of nitrate nitrogen (21-16 mg/kg). In wheat fields cultivated under intensive conditions, the supply of Р2О5 corresponded to an increased and average supply of this nutrient (210-195 mg/kg). Leaving the soil fallow for 27 years resulted in a decrease in the content of mobile phosphates to low and very low levels (52-130 mg/kg).