How Does Biochar and Biochar With Nitrogen Fertilization Influence Soil Reaction?

Biochar usually has a neutralizing effect, therefore, it is recommended for application to acid soils due to its potential to increase soil pH. The aims of this study were (1.) to quantify the role of different rates of biochar and biochar in combination with N fertilization on change of soil pH, and (2.) to evaluate the dynamic changes of soil pH in relation with doses of biochar and biochar with N fertilization. A field experiment was conducted with different biochar application rates: B0 control (0 t ha^-1), B10 (10 t ha^-1) and B20 (20 t ha^-1) and 0, 40 and 80 kg N ha^–1 of nitrogen fertilizer (N0, N40, N80) on silt loam Haplic Luvisol at the locality of Dolná Malanta (Slovakia) in 2014. Their effects were investigated after vegetation season of spring barley and spring wheat (once a month: from April to July) in 2014 and 2016, respectively. Experimental results indicate that the soil pHH₂O in B0N0, B10N0, B20N0, B10N40, B20N40, B10N80 and B20N80 were 6.23, 6.45, 6.60, 6.77, 6.48, 6.36 and 6.60, respectively. The results of LSD test showed statistically significant differences between soil pH in control treatment and treatments with biochar and biochar with N fertilization. The most significant effect on increase of soil pH was observed in B10N40. During whole period, after application of biochar and biochar with N fertilization the values of pHKCl were gradually decreased in all treatments.