The influence of liquid organic fertilizers forms on ecologically grown potatoes

Investigation of the effect of liquid organic fertilizers on organically grown potatoes were carried out in light clay loam, shallow gleysol carbonaceous illimerised soils - Calc(ar) i-Epihypogleyic Luvisol - LVg-p-w-cc - at the experimental station of Aleksandras Stulginskis University in Lithuania in 2013-2014. The experiments were carried out with liquid organic fertilizers Biokal 1 and Fitokondi, in the manufacture of which herbal extracts were used; fertilizers Fertenat and Ruponis made from biohumus, and fertilizers Humistar rich in humic and fulvic acids. The forms of liquid organic fertilizers had an uneven influence on organic potatoes. The potatoes, which were sprayed with Biokal 1 fertilizer, total yield of potato tubers essentially increased by 0.89-1.47 t ha-1 or 5.34-9.14%, and marketable yield increased by 0.89-1.54 t ha-1 or 10.24-19.15% compared to spraying with fertilizers Fitokondi, Humistar, Fertenat and Ruponics, and no significant differences in the output of marketable yield were determined. Under the influence of Biokal 1, the content of dry matter in potato tubers compared to spraying with Ruponics and the starch content compared to spraying with Ruponics, Humistar and Fertenat substantially increased, and the content of nitrates in potato tubers significantly decreased compared to potato spraying with fertilizers Ruponics and Humistar. After spraying potatoes with fertilizer Biokal 1, the number of one-stem tubers compared to spraying with Humistar, Fertenat and Ruponics, substantially increasedKauno statybos ir paslaugų mokymo centrasVytauto Didžiojo universitetasŽemės ūkio akademij