Biochar - A Panacea for Agriculture or Just Carbon?

The sustainable production of food faces formidable challenges. Foremost is the availability of arable soils, which have been ravaged by the overuse of fertilizers and detrimental soil management techniques. As such, maintenance of soil quality, and reclamation of marginal soils, has become an increasingly important endeavor. Recently, there has been emerging interest in the use of biochar, a carbon rich, porous material thought to improve various aspects of soil performance. Biochar (BC) is produced through the thermochemical decomposition of organic matter at high temperature in an oxygen limited environment, in a process known as pyrolysis. Importantly, the source of organic material, or ‘feedstock,’ used in this process and different parameters of pyrolysis, especially temperature, determine the chemical and physical properties of biochar. Incorporation of BC impacts soil-water relations, tilth and nutrient status, pH, soil organic matter (SOM), and microbial activity. Soil amendment with BC has been shown to have an overall positive impact on soil health and crop productivity; however, initial soil properties need to be considered prior to the application of BC. There is an urgent need to understand the effects of long-term field application of BC and how it influences the soil microcosm. This knowledge will facilitate predictable enhancement of crop productivity and meaningful carbon sequestration.