Effects of Biochar and its Reapplication on Soil pH and Sorption Properties of Silt Loam Haplic Luvisol

In this paper we investigate the effects of biochar alone and its reapplication and combination with N-fertilizer (1) on the soil pH, and (2) sorption parameters. The soil samples were taken during growing period in 2018 from plots with different biochar (first application in 2014 – A, reapplication in 2018 – B) at application rates: 0 t.ha⁻¹ (B0 control), 10 t.ha⁻¹ (B10) and 20 t.ha⁻¹ (B20) and different nitrogen fertilization: N0 (no nitrogen) and N40 (40 kg.ha⁻¹). Our results showed that the first application of biochar at the rate of 20 t.ha⁻¹ (B20A) without N-fertilizer significantly increased the values of soil pH in H₂O, soil pH in KCl, the sum of base cations (SBC) and cation exchange capacity (CEC) compared to control (B0). Similar effects were observed also after reapplication of biochar (B10B). All investigated parameters in fertilized control treatment (B0N40) were worst and the first application, as well as the reapplication of biochar with N, caused significant increase of soil pH in H₂O, soil pH in KCl, SBC, CEC, BS and decrease of hydrolytic acidity.