“…The effect of biochar as soil amendment and its effect on sandy soils and crop yield has been studied at various scales (Atkinson et al, 2010;Brockhoff et al, 2010;Jeffery et al, 2011Jeffery et al, , 2015Uzoma et al, 2011;Basso et al, 2012;Githinji, 2013;Nelissen et al, 2014;Molnár et al, 2016), confirming that the extent of the effects of biochar on soil depends on the biochar production conditions and feedstock (Nelissen et al, 2014;Molnar et al, 2016), the soil type (Basso et al, 2012;Githinji, 2013), the climatic conditions (Atkinson et al, 2010;Nelissen et al, 2014), the polycyclic aromatic hydrocarbon (PAH) content (Hale et al, 2012) and trace metal level of the biochar (Freddo et al, 2012) and the biochar ageing process (Zhao et al, 2015). Biochar could be used with organic amendments to increase their stability and reduce organic matter solubility (Ngo et al, 2013(Ngo et al, , 2014Doan et al, 2014), with positive effects on soil fertility, maize growth and yield, and nutrient retention, while mitigating erosion of degraded acidic sandy soils (Doan et al, 2015).…”