The effects of biochar applications on the pH of the Black Sea region soil and some biological activity parameters

Tea plant cultivation in Turkey is carried out only on the coastline located between the town of Fatsa and the Georgian border which has microclimatic features. For many years, monoculture cultivation, together with climate and human factors, soil fertility has been threatened and caused a decrease in soil pH. In this study, it was aimed to evaluate the effects of biochar that obtained from tea pruning residues on soil pH and biological activities of the soils of the Black Sea region. Experimental soil and tea pruning residues were obtained from the tea gardens in the central district of Rize, Yeni Kale village, and a 4-month incubation experiment was established as the laboratory experiment. The pruning residues were subject to pyrolysis at 300 °C, 400 °C, and 500 °C in an oxygen-free environment and incorporated into the soil at 0, 0.5% and 0.1% rates. Every 30 days, soil samples were taken and soil respiration rate (CO2 formation), urease, protease, amylase, beta glucosidase enzyme activities, mineral nitrogen (NH4+, NO2- and NO3-) concentrations and soil pH were determined. The results of the study revealed that biochar applications obtained from tea pruning residues may increase soil pH, protease and beta glucosidase enzyme activities, and mineral nitrogen forms as NH4+, and NO3- concentrations, in terms of average values.