Influence of humic acids, irrigation and fertilization on potato yielding in organic production
The study aimed at determining the impact of organic fertilization, humic acids and irrigation on potato yielding in organic production system. Fertilization variants included: Humac Agro; manure; vermicompost; Fertil Bioilsa C-N 40-12.5; manure + Humac Agro; vermicompost + Humac Agro; Fertil Bioilsa C-N 40-12.5 + Humac Agro. Irrigation was carried out using drip lines. The highest tuber yield was determined on treatments fertilized with vermicompost. The combined application of organic fertilizers and humic acids resulted in increased total yield between 6 and 9%, whereas commercial yield from 5 to 10%. Application of fertilization resulted in increased total yield of tubers in individual fertilizer variants from 1.9 to 10.8 t ha-1 , and commercial yield from 1.6 to 12.3 t ha-1 . Water-use efficiency remained in the range from 35.2 to 113.1 kg mm-1 , whereas irrigation water-use efficiency from 9.9 to 166.3 kg mm-1 . Humic acids used in the study enhanced fertilizer and water-use efficiency.