THE EFFECTS OF HUMIC ACID PRODUCT ON SOIL FERTILITY MEASURED BY RYEGRASS TEST PLANT

László TOLNER - Ferenc SÁNDOR - Barbara SIMON - György FÜLEKY

Department of Soil Science and Agricultural Chemistry, Institute of Environmental Science, Faculty of Agricultural and Environmental Sciences, Szent István University, H-2103 Gödöllő, Páter K. str. 1., tolner.laszlo@gmail.com

Abstract: Soil fertility can be influenced by the use of humic acid. The humic acid that we used in our experiments originated from South Africa. It was produced by Farmfert Formulators INC. and registered under the code number of PCT WO 2006/092720AI. The extraction of the humic substances from mineral coal, organic compost or both involved three steps. During the first step, oxidizing reagent (HNO₃) was added to the raw material under atmospheric pressure in a reactor. This initiated an exothermic chemical reaction. The second step was to separate the fulvic acid from the intermediary product into a solution using pyroligneous acid. The remaining deposit in the bottom of the reactor contained the humic acid, which was extracted during the third step resulting from the treatment with potassium-hydroxide.

The effects of humic acid application were measured in three doses (0.075; 0.5; 10%) in laboratory in a pot experiment by ryegrass test plant. Dry matter yield and macro element content of ryegrass plants were measured. The highest yield was measured in case of the 0.5% treatment. The 10% dose caused yield depression, however, in this treatment the nitrogen uptake was the highest. The highest phosphorus uptake was measured in case of the lowest dose of humic acid application. The potassium uptake did not respond significantly to the humic acid treatment.

Keywords: soil fertility, humic acid, fertilisation