Effects of two different biochar on physical quality characteristics of a heavy clay soil

In recent years, due to resistance to decomposition and fragmentation, the use of organic residues as a soil improver by converting organic residues to biochar has become widespread in order to create a long-term lasting effect. Improving the structural properties of soils with poor physical quality and high clay content has a considerable importance in ensuring fertility and sustainability of the soil. Therefore, the effect of biochar produced from chicken manure (CMB) and cattle manure (CTB) on the characteristics of physical quality of a soil with poor structural properties was determined under incubation study. In this context, soil samples that had CMB and CTB in the doses of 0, 0.25, 0.50, 1, and 2% on a weight basis were left to incubation for 30–60-90 days at field capacity moisture content, and thereafter, the impacts of their applications on the soil characteristics of physical quality were determined. Based on the findings obtained from the incubation samples, when comparing the highest applied dose of CHB and CTB with the control, aggregate stability (AS) increased by 65 and 64%, the mean weight diameter (MWD) increased by 81 and 53% and field capacity (FC) increased by 3 and 2%, respectively, while the modulus of rupture (MR) decreased by 59 and 57%, and the dispersion rate (DR) decreased by 14 and 5%, respectively. The effectiveness of biochars on the physical quality characteristics of the soil varied with incubation time, but similar trends were observed. It has been evaluated that chicken and cattle manure biochars can be used in the improvement and development of the physical quality properties of the heavy clay soils, but the obtained results should be validated by long-term field studies.