The influence of different farming systems on the content of mobile potassium compounds in the soil

Goal. Based on observations in the system of agroecological monitoring in a stationary field experiment of the Right-Bank Forest Steppe, to establish the peculiarities of the dynamics of mobile compounds of potassium under different farming systems. Methods. Agroecological monitoring and laboratory method (chemical, physicochemical analysis using modern methods of atomic absorption spectrophotometry, flame photometry, mathematical-statistical analysis following the requirements of the quality management system, DSTU 39732000). Results. The results of the studies conducted on the dark gray podzolized soil of the Right-Bank Forest Steppe in the long-term research of the department of technology of grain ear crops (1987–2022) of the NSC "IA of NAAS" (Fastiv district, Kyiv oblast) are given. During the years of research under an extensive system of agriculture, which involved the periodic introduction of meliorants and the annual cultivation of post-harvest residues, the content of mobile potassium compounds did not undergo significant changes (V=12.1%) and was in the range of 79.0–105.0 mg/kg (on average for 1987–2022 — 93.9 mg/kg). The annual application of by-products in a dose equivalent to 5 t/ha of straw and the periodic application of ameliorants under the organic farming system contributed to an increase in mobile potassium compounds in the soil compared to the indicators under the extensive system by almost 1.2 times, which amounted to an average of 109.6 mg/ kg. Intensive farming systems No. 1 (N70P57.5K67.5) and No. 2 (N105.0P86.3K101.3) provided the content of mobile potassium compounds, respectively, at the level of 146.0 and 201.4 mg/kg, which 1.6 and 2.1 times exceeded such indicators under the extensive farming system. Under the intensive system No. 3 with N70P28.8K33.8 application on the background "in reserve" of 2100 kg/ha of P2O5 and 4700 kg/ha of K2O, the content of mobile potassium compounds was 317.6 mg/kg. Conclusions. The results of research during 1987–2022 indicated the impact of organic and intensive farming systems on the content of mobile potassium compounds in the soil. The use of an organic farming system, which provided periodic introduction of meliorants as well as annual introduction of by-products at a dose equivalent to 5 t/ha of straw, contributed to the growth of mobile potassium compounds in the soil by 1.2 times compared to the indicators under the extensive system, which indicated an increase in the stock of mobile compounds potassium in the arable layer of the soil. The introduction of various variants of intensive farming systems made it possible to increase the number of mobile potassium compounds in the soil by 1.6–3.4 times. It should be noted that the use of potash fertilizers "in reserve" with the annual application of mineral fertilizers in a dose of N70P28.8K33.8 (intensive farming system No. 3) contributed to the constant maintenance of a high content of mobile potassium compounds in the arable layer of the soil.