Biochar is a charcoal that is used to improve land rather than as a fuel. Biochar is produced from biomass, usually through the process of pyrolysis. Due to the molecular structure and strength of the chemical bonds, the carbon in biochar is in a stable form and not readily mineralized to CO2 (as is the fate of most of the carbon in biomass). Because the carbon in biochar derives (via photosynthesis) from atmospheric CO2, biochar has the potential to be a net negative carbon technology/carbon dioxide removal option. Biochar is not a single homogeneous material. Its composition and properties (including longevity) differ according to feedstock (source biomass), pyrolysis (production) conditions, and its intended application. This variety and heterogeneity have so far eluded an agreed methodology for calculating biochar’s carbon abatement. Meta-analyses increasingly summarize the effects of biochar in pot and field trials. These results illuminate that biochar may have important agronomic benefits in poorer acidic tropical and subtropical soils, with one study indicating an average 25% yield increase across all trials. In temperate soils the impact is modest to trivial and the same study found no significant impact on crop yield arising from biochar amendment. There is much complexity in matching biochar to suitable soil-crop applications and this challenge has defied development of simple heuristics to enable implementation. Biochar has great potential as a carbon management technology and as a soil amendment. The lack of technically rigorous methodologies for measuring recalcitrant carbon limits development of the technology according to this specific purpose.
Holly Morgan, Saran Sohi, and Simon Shackley
In 2018 barley accounts for only 5% of the cereal production worldwide, and regionally for up to 40% of cereal production. The cereal represents the oldest crop species and is one of the best adapted crop plants to a broad diversity of climates and environments. Originating from the wild progenitor species Hordeum vulgare ssp. spontaneum, biogeographically located in the Fertile Crescent of the Near East, the domesticated form developed as a founder crop in aceramic Neolithic societies 11,000 years ago, was cultivated in monocultures in Bronze Age Mesopotamia, entered the New World after 1492 ce, reached a state of global distribution in the 1950s and had reached approximately 200 accepted botanical varieties by the year 2000. Its stress tolerance in response to increased aridity and salinity on one hand and adaptability to cool climates on the other, partially explains its broad range of applications for subsistence and economy across different cultures, such as for baking, cooking, beer brewing and as an animal feed. Although the use of fermented starch for producing alcoholic beverages and foods is globally documented in archaeological contexts dating from at least the beginning of the Holocene era, it becomes concrete only in societies with a written culture, such as Bronze Age Mesopotamia and Egypt, where beer played a considerable role in everyday diet and its production represented an important sector of productivity. In 2004 approximately 85% of barley production was destined for feeding animals. However, as a component of the human diet, studies on the health benefits of the micronutrients in barley have found that it has a positive effect on blood cholesterol and glucose levels, and in turn impacts cardiovascular health and diabetes control. The increasing number of barley-breeding programs worldwide focus on improving the processing characteristics, nutritional value, and stress tolerance of barley within the context of global climate change.