Short-Term Impacts of Biochar Applications on Physico-Mechanic and Chemical Properties af Two Contrasting Textured Soils

Abstract

The effect of biochar applications on soil properties varies significantly depending on soil textures. Therefore, a pot experiment was carried out to investigate the effects of biochar (BC) amendment on some soil physico-mechanic and chemical properties, such as bulk density (BD), particle density (PD), mean weight diameter (MWD), aggregate stability (AS), Attarberg limits, soil pH, electric conductivity (EC), organic carbon (OC), total nitrogen (TN), and C:N ratio of two different textured calcareous soils (Clay and Sandy Loam). Biochar produced from sunflower residues were mixed with soils at the rate of 0, 1, 2 and 4%. All pots were watered to field capacity and incubated for 30 days. The results showed that biochar improved soil structural properties for both studied soils. Although mean weight diameter (MWD) was increased in clay soil, it was decreased in sandy loam soil. The liquid limit was increased by an increment of BC application rates in both soils, and the plastic limit was increased in single clay soil. BC affected selected soil chemical properties by decreasing soil pH, and increasing the soil EC, OC, TN, and C: N ratio, but no effect was detected on CaCO3 content in both soils. Organic carbon mineralization ratio increased in the clay soil amended with BC, however, decreased in the sandy loam soil compared with the control sample. As a conclusion, the biochar amendment improved soil physico-mechanic properties of the studied soils. However, the effect on chemical properties was inconsistent.