The Effect of Walnut Wood Biochar and Bentonite on Electrical Conductivity and Soil Permeability

In recent years, the use of soil amendments with the aim of improving texture or increasing water capacity has become popular. This can affect the physical or chemical properties of the soil. In the present study, changes in electrical conductivity and soil permeability due to the addition of biochar and betonies were investigated. For this, 13 samples with two levels of 2% and 3% walnut wood biochar at two temperatures of 400°C and 600°C, were prepared, together with three levels of 2%, 5% and 10% bentonite and one soil sample without materials was used. The samples incubated for five months. The t-test was also used to check the difference between the samples. The results showed that both biochar and bentonite are able to significantly increase EC and decrease soil permeability. The average permeability value for samples with 2 and 3 percent biochar is a quarter of the permeability of soils without amendment. Adding bentonite to the soil reduced permeability such that the permeability of samples containing 10% bentonite (0.25 mm/min) was approximately ten times lower than that of the control sample (2.6 mm/ min). The electrical conductivity value in the samples with 10% bentonite is more than 4 times higher than in the soil without amendment, and in the samples with 2 and 3% biochar, it is on average about 2.3 times higher. Considering the increase in soil electrical conductivity, it is recommended to use biochar and bentonite with more accuracy.