*3.1.4 Nutrient availability in soils*

Biochar application leads to the increase in pH of the soil and that leads to improved availability of phosphorous and potassium [9] When biochar is applied on the soil, oxidation process is observed on the surface of particles. The reason for the reported high CEC is the oxidation of aromatic carbon which leads to the formation of carboxyl groups [24]. With the increase in CEC the nutrients will remain attached to the soil opposing the leaching process. When highly oxidized organic matter attached with the surface it will create negative charge on the surface. As a result, positive charge on these sites gets decreased. However, the results from the studies showed that the effect of biochar is more expected on the soils having macro pores [25].
