Abstract
The purposes of the study were to evaluate the effect of treating spring barley seeds with different concentrations of a biostimulant derived from potato production waste on the growth and development of seedlings and plants as well as on their susceptibility to fungal pathogens and to compare this effect with that of other biologically active preparations. The study was carried out on seeds and seedlings (including a phytosanitary examination of seeds and assessment of their germination and indices of development) as well as on plants grown in a climate chamber on a sand substrate for 26 days (determination of growth and development indices, chlorophyll content, and level of affection with foliar diseases). The experimental design included several biostimulant concentrations (10–4, 10–5, and 10–6 mL/L ( \({\text{BS}}_{{10}}^{{ - 4}},\) \({\text{BS}}_{{10}}^{{ - 5}},\) and \({\text{BS}}_{{10}}^{{ - 6}}\) ); growth regulators Zircon, S (1 mL/L, 10 L/t), and Epin-Extra, S (200 mL/t); a concentrated liquid organic fertilizer Natur Agro ECO GROW (20 and 30 mL/L (Fertilizer 1, Fertilizer 2)); and N, N'-diphenylurea (DPU) at concentrations of 2 × 10–3 and 3 × 10–3 mL/L (DPU 1, DPU 2). Seeds treated with distilled water were considered as a control. After the seed treatment with the biostimulant at concentrations of 10–4 and 10–5 mL/L, an increase in the length of the main embryonic root by 12 and 8%, respectively, as well as in the root mass of seedlings, was observed. In the case of a biostimulant concentration of 10–6 mL/L, an enhanced plant-growth rate (+8.8%) and chlorophyll accumulation in the leaves (+23.0%) were observed. The efficiency of the biostimulant application in relation to the seedling development and the chlorophyll content was comparable to or exceeded that of Zircon, S and Epin-Extra, S. The seed treatment with the organic fertilizer and diphenylurea promoted more intensive plant development by 5.5–10.3 and 3.1–17.9%, respectively, compared to the control. The occurrence of foliar diseases on treated plants ranged from 60 to 80%, while their severity when using the biostimulant (10–4 and 10–6 mL/L) or fertilizer and DPU (3 × 10–3 mL/L) was significantly lower compared to the control.
