PUBLIC MARKS from paleorthid with tags "carbon sequestration" & bio-char

The Godfather of Terra Preta, soil scientist Wim Sombroek (1934 - 2003) enjoyed a lifelong fascination with enhanced soil. The importance of plaggen soil in his native Netherlands impressed him at an early age, and early in the 1960's, he recognized in the Amazonian Dark Earths something familiar and precious. Before his passing, he assembled specific soil scientists challenged them to discover the process for making and sustaining a modern equivalent of the bio-char enhanced terra preta, what he termed terra preta nova. A great opportunity in answering Sombroek's challenge lies is surmounting the opacity of mutualistic rhizospheric species to traditional analytical approaches: only 1% of rhizospheric species are cultureable ala petri dish. We don't have a robust body of culture-independent studies against which to compare Terra Preta, so we are doubly challenged to reverse-engineer the phenomenon. Considering Wim Somboek's many noteworthy accomplishments, the perspective of his international leadership, and the late-in-life timing of his challenge, one senses he is pointing us to a mystery fundamental to understanding soil in new and exciting ways. This happens at a time when the soil science profession is in dynamic transition and sorely in need of a unifying vision. Wim Sombroek has given soil scientists a most welcome and worthy quest.

Rapid turnover of organic matter leads to a low efficiency of organic fertilizers applied to increase and sequester C in soils of the humid tropics. Charcoal was reported to be responsible for high soil organic matter contents and soil fertility of anthropogenic soils (Terra Preta) found in central Amazonia. Therefore, we reviewed the available information about the physical and chemical properties of charcoal as affected by different combustion procedures, and the effects of its application in agricultural fields on nutrient retention and crop production. Higher nutrient retention and nutrient availability were found after charcoal additions to soil, related to higher exchange capacity, surface area and direct nutrient additions. Higher charring temperatures generally improved exchange properties and surface area of the charcoal. Additionally, charcoal is relatively recalcitrant and can therefore be used as a long-term sink for atmospheric CO2. Several aspects of a charcoal management system remain unclear, such as the role of microorganisms in oxidizing charcoal surfaces and releasing nutrients and the possibilities to improve charcoal properties during production under field conditions. Several research needs were identified, such as field testing of charcoal production in tropical agroecosystems, the investigation of surface properties of the carbonized materials in the soil environment, and the evaluation of the agronomic and economic effectiveness of soil management with charcoal.