The fluctuation of molybdenum content in oilseed rape plants after the application of nitrogen and sulphur fertilizers

The effect of N-S fertilizers on the molybdenum content in. rape plants was investigated in precision field trials. Evaluation was carried out on unfertilized control and two treatments of single fertilizer rates in the first spring fertilizer application, using 100 kg N/ha in AN treatment (nitrochalk) and 100 kg N/ha + 50 kg S/ha in ANS treatment (ammonium nitrate and ammonium sulphate). The results confirmed the significance of sulphur fertilization for the winter oilseed rape plant's cultivation technology, even on fertile soils in the Czech Republic. The control treatment produced a yield of 3.7 t/ha, while in the AN treatment the yield was 49% higher, and the ANS treatment was 60% higher. An antagonistic relationship between the sulphate and molybdenum anions in their absorption by the plants was demonstrated. The molybdenum content in the flowering period of the plants was determined in mg/kg as follows in the ANS treatment: 0.17 in root, 0.12 in stem, 1.56 in upper leaves, 0.90 in lower leaves, and 1.17 in the flower petals. Higher and statistically more significant molybdenum levels were determined in the AN treatment: 0.21 in the root, 0.19 in the stem, 2.40 in the upper leaves, 1.72 in the lower leaves, and 1.50 mg/kg in the flower petals. The total above-ground biomass of the plants in the flowering period had accumulated molybdenum at 6.06 g/ha in the ANS treatment, and 8.44 g/ha in the AN treatment.