New York Times: Simmered out of eucalyptus, charcoal is being hoed into the degraded soils of former forests in western Kenya. Roasted out of chicken manure, it is spurring the growth of malting barley in Australia. And in Iowa, researchers are plowing charcoal into corn rows, hoping to limit the tons of fertilizer that saturate the state’s fields each year. At these farms and more, scientists are probing the limits of how high-grade charcoal, dubbed biochar, can be formed from plant and animal waste …