Herbicide stress and biostimulant application influences the leaf N, P and K content of sunflower

The aim of the study conducted between 2017 and 2019 is to evaluate the influence of the herbicide stress caused by imitation of "mistaken" treatment of the ExpressSunR sunflower hybrid P 64 LE 25 with imazamox to the leaf N, P and K content of plants before flowering stage. Treatments of the experiment were: 1. Untreated control;2. PulsarR Plus - 2.00 l ha-1 (25 g/l imazamox);3. PulsarR Plus - 2.00 l ha-1 + Amino Expert Impuls - 3.00 l ha-1 (biostimulant). The herbicide was applied in 4th - 6th true leaf stage of the crop. At treatment 3, biostimulant was applied four days after the herbicide intervention. An increase in the leaf N content after the medicative biostimulant application average for the period was found. No influence of the "mistaken" treatment on the P content in the leaves was recorded. The plants treated "mistakenly" with PulsarR Plus (2.00 l ha-1) had increased K levels in the leaves. This increased K content was probably due to high abiotic stress. K, in turn, helps the plants to overcome the stressful conditions to some extent.