D.A.C. Manning, P. Renforth, E. Lopez-Capel, S. Robertson, N. Ghazireh
The proportions of different carbon pools within artificial soils prepared by blending composts with dolerite and basalt quarry fines has changed over a period of 7 years, accumulating inorganic carbon as carbonate minerals newly formed within the soils. With no artificial energy inputs following construction, this is regarded as a passive mineral carbonation process. Carbon isotope data show that up to 40% of the carbon within the soil carbonate is derived from photosynthesis, mixed with carbon from geological sources (limestone present in the quarry fines). ...
Soils are the dominant terrestrial sink for carbon, containing three times as much C as above-ground plant biomass, and acting as a host for both organic and inorganic C, as soil organic matter and pedogenic carbonates, respectively. This article reviews evidence for the generation within the soil solution of dissolved C derived from plants and recognition of its precipitation as carbonates. It then considers the potential value of this process for artificially-mediated CO2 sequestration within soils. The ability of crops such as wheat to produce organic acid anions as root exudates is substantial, generating 70 ...
P.Renforth, D.A.C.Manning, E.Lopez-Capel
Turnover of C in soils is the dominant flux in the global C cycle and is responsible for transporting 20 times the quantity of anthropogenic emissions each year. This paper investigates the potential for soils to be modified with Ca-rich materials (e.g. demolition waste or basic slag) to capture some of the transferred C as geologically stable CaCO3. To test this principal, artificial soil known to contain Ca-rich minerals (Ca silicates and portlandite) was analysed from two sites across NE England, UK. The results demonstrate an average C content of 30±15.3 Kg C m^-2 stored as CaCO3, ...
Recently published assessments of nutrient budgets on a national basis have shown that K deficits for developing countries are so substantial that a doubling of world production of potash fertilisers would be required to balance inputs and offtake, simply to meet demands in Africa alone. The price of potassium fertiliser raw materials has increased by a factor of 4 during 2007–2009, approaching $1000 per tonne in some markets. Thus an annual investment of the order of US$5600 million is required to replenish soil K stocks in Africa. In this context it is appropriate to review current knowledge of alternative sources of ...
P. Renforth*, C.-L. Washbourne, J. Taylder, and D. A. C. Manning
Atmospheric carbon dioxide sequestered as carbonates through
the accelerated weathering of silicate minerals is proposed as a climate change
mitigation technology with the potential to capture billions of tonnes of carbon
per year. Although these materials can be mined expressly for carbonation, they
are also produced by human activities (cement, iron and steel making, coal
combustion, etc.). Despite their potential, there is poor global accounting of
silicates produced in this way. This paper presents production estimates (by
proxy) of various ...