Effects of biochar on soil fertility and crop productivity in arid regions: a review
Biochar, carbon-rich materials produced during the thermochemical processing of biomass, are receiving increased attention given their potential value as soil amendments. Biochar are formed through pyrolysis processes—heating to several hundred degrees Celsius under oxygen-limited environments—and both the source feedstock and the reaction conditions affect the quality of the resulting chars. Biochar can enhance soil physical and chemical properties and increase agricultural systems’ productivity through direct and indirect effects on crop growth and soil quality. Biochar also may directly help mitigate climate change by sequestering stable carbon compounds in the soil and perhaps indirectly through increased C uptake by trees. As the world faces growing challenges from soil degradation and climate change, biochar application to soils represents a potential pathway forward. Although a large volume of literature exists regarding the use of biochar under favorable climatic conditions, information regarding biochar applications in semiarid and arid climates has been more limited. Evidence of greater water holding capacity and reduced infiltration suggests these materials have potential to improve the productivity of such lands and provides a basis for considering its wider application in the arid environments such as Saudi Arabia. Challenges and limitations for biochar use on a mass scale are also briefly discussed. To move this technology forward, crop and soil scientists should involve economists and agricultural extension educators in studies that consider economic as well as biophysical implications for biochar’s application on a mass scale.