TRACE ELEMENT CONTENT IN SOD-PODZOLIC SOIL AND MAIN CROP PRODUCTS IN A FIVE-FIELD CROP ROTATION AS AFFECTED BY FERTILIZER RATES

Abstract

A stationary field experiment was conducted on sod-podzolic soil to determine the effect of fertilizer application rates on the concentration of trace elements in soil and major crop products within a five-field grain–row crop rotation. The trial was established in 2015 in Khrystynivka village (Narodychi district, Zhytomyr region, Ukraine), located within the second zone of radioactive contamination. The cultivation practices followed standard technologies recommended for the region, and chemical crop protection products were applied in accordance with the experimental scheme to ensure competitive marketable yields. The findings obtained over 2015–2019 clearly indicate that both fertilizer rate and crop rotation structure exerted a significant influence on trace element distribution in the soil and harvested plant products. On average across crop rotations, the soil was characterized by low to very low trace element availability: Cu – 0.091 mg/kg, Co – 0.158 mg/kg, Mn – 6.15 mg/kg, Zn – 2.27 mg/kg, B – 0.87 mg/kg, and Mo – 0.083 mg/kg. Higher values were observed under fertilizer application, particularly at the second rate. Nevertheless, the necessity for additional micronutrient supplementation remains evident, especially for sensitive crops such as oats, lupine, and triticale. Trace element concentrations in crop products were within maximum permissible limits for feed and food use. The highest copper accumulation occurred in triticale grain (4.84 mg/kg), zinc in lupine seeds (40.61 mg/kg), and cobalt, manganese, and iron in fodder beet roots (0.923, 30.05, and 50.85 mg/kg, respectively). The second fertilizer rate was the most effective overall, whereas maize grain exhibited the lowest trace element content.