Components of photosynthetic activity and potato yield under organic production

Abstract

Objective. To determine the effect of green manure crops, organic fertilizers (cattle manure), biostimulants, and biological preparations on the formation of photosynthetic parameters and potato yield under organic cultivation conditions in the Southern Polissia of Ukraine. Methods. General scientific and special methods, including field stationary experiments, measurement and weight, and statistical and mathematical methods. The research was conducted during 2023–2025 at the Institute for Potato Research using the mid-ripening potato variety Myroslava. Two fertilization backgrounds were used: double green manure of white mustard with subsequent incorporation into the soil, and double green manure of white mustard + 40 t/ha of cattle manure compost with subsequent incorporation. Biostimulants “Biohran”, “StimPure AA Liquid”, “Humifield”, “VIT-ORG VG”, and biofungicides “Mycohelp” and “Phytohelp” were applied. Results. The leaf area of potato plants under the organic growing system varied depending on the growth and development phases. The maximum assimilation surface area was recorded at the “green berry” stage regardless of the fertilization background and biopreparations. The highest indicators were observed when using the growth bioregulator “VIT-ORG VG” and the biofungicide “Mycohelp” – 33.3 and 34.6 thousand m2/ha, exceeding the control variant of background 1 and background 2 by 20.6 % and 19.7 %, respectively. The net photosynthetic productivity reached its maximum during the “emergence–budding” phase: 9.7–12.8 g/m²/day on background 1 and 10.8–13.8 g/m²/day on background 2. In the subsequent growth stages, NPP gradually decreased, reaching its lowest levels at the onset of haulm senescence – 6.2–9.6 g/m2/day on the double white mustard green manure background, and from 7.2 g/m²/day in the control variant to 10.5 g/m2/day in the variant treated with the biostimulant “VIT-ORG VG” and the biofungicide Mycohelp on the double white mustard green manure background and cattle manure compost. The average tuber yield without biostimulants and biofungicides was 22.3 t/ha on background 1 and increased by 5.3 t/ha on background 2 (27.6 t/ha). The use of biopreparations positively influenced potato yield, with an increase of 0.7–3.3 t/ha on background 1 and 0.6–4.7 t/ha on background 2. The highest yields were obtained on background 2 with “VIT-ORG VG” + “Mycohelp” (32.3 t/ha) and with “Biohran + StimPure AA Liquid” + “Mycohelp” (31.8 t/ha), exceeding the control variant by 17 % and 15.2 %, respectively. Conclusions. The components of photosynthetic activity (leaf area, leaf area index, net photosynthetic productivity, and photosynthetic potential) dynamically changed depending on the nutrient background, biostimulants, and biofungicides. Their use enhanced the efficiency of nutrient utilization from organic fertilizers and had a positive effect on the yield increase of the Myroslava potato variety by 14.8–17.8 %.