Effect of various doses of birch-derived biochar on the growth of Helianthus annuus L.

Abstract

Although biochar (BC) is expected to improve soil properties and plant growth, few studies have confirmed its effect on Helianthus annuus L. (sunflower). The effects of four different concentrations of birch-derived BC (2.5, 5, 7.5, and 10%) on the biometric growth parameters of sunflower were studied in a 60-day pot-scale experiment. In addition, the physicochemical properties and elemental composition of the birch-derived BC and peat substrates were examined. It is noted that birch-derived BC was characterized by a slightly acidic pH (about 6.4), lower electrical conductivity and 3.4 times higher water-holding capacity compared to the control substrate. Moreover, the percentage of carbon in BC was 1.4 times higher, while the content of hydrogen and oxygen, on the contrary, was lower in 1.5 and 2.0 times than in the control substrate. In most cases, adding BC to the peat substrate improved H. annuus growth parameters such as shoot height, root length, leaf area, as well as total fresh and dry biomass. The best results were obtained by adding 5% BC, which had a positive effect on all biometric parameters of H. annuus plants, while 10% BC had the least impact.