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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Adaptive Cropping Systems Laboratory » Research » Publications at this Location » Publication #312463
Title: Agromining: Farming for metals in the future?

Author
item VAN DER ENT, ANTONY - University Of Queensland
item BAKER, ALAN - University Of Melbourne
item REEVES, ROGER - University Of Melbourne
item Chaney, Rufus
item ANDERSON, CHRISTOPHER - Massey University
item ERKSINE, PETER - University Of Queensland
item SIMONNOT, MARIE-ODILE - Université De Lorraine
item VAUGHAN, JAMES - University Of Queensland
item MOREL, JEAN-LOUIS - Université De Lorraine
item ECHEVARRIA, GUILLAUME - Université De Lorraine
item FOGLIANI, BRUNO - Agronomic Institute Of New Caledonien
item MULLIGAN, DAVID - University Of Queensland

Submitted to: Environmental Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/4/2015
Publication Date: 2/20/2015
Citation: Van Der Ent, A., Baker, A.J., Reeves, R.D., Chaney, R.L., Anderson, C.W., Erksine, P.D., Simonnot, M., Vaughan, J., Morel, J., Echevarria, G., Fogliani, B., Mulligan, D.R. 2015. Agromining: Farming for metals in the future? Environmental Science and Technology. 49:4773-4780. doi: 10.1021/es506031u.

Interpretive Summary: Phytomining technology employs hyperaccumulator plants to sequester a metal in harvestable plant biomass. These plants are grown on sub-economic mineralization or on the wastes from the minerals industry. Harvesting, drying, and incineration of the biomass generates a commercial high-grade bio-ore. ‘Agromining,’ a variant of phytomining, would provide local communities in developing countries opportunities for an income stream as an alternative type of agriculture, farming not for food crops, but for metals such as Ni. However, two decades after its inception and numerous successful scientific experiments, commercial phytomining has not yet become a reality. Here we identify target regions of the world and strategies for implementation and argue that for commercial adoption of phytomining on a large-scale, successful demonstrations are still needed. Apart from the local environmental benefits from the technology, the potential social benefit via contributions to livelihoods and local economies are a strong argument for the further development of agromining.

Technical Abstract: Over the last two decades, phytomining (an agricultural technology using plants to accumulate soil metals into harvestable shoot biomass) was developed, but due to patents on the technology and failure of the patent licensee to commercialize the technology, phytomining has not been adopted by industry. A “Phytomining Workshop” held at the University of Queensland, Australia, in July 2014 reviewed the scientific progress in understanding Ni hyperaccumulating plant species, the development and demonstration of the potential of phytomining, and the adoption of phytomining for small farmers, agromining. The manuscript is a summary of the science which supports the potential of phytomining/agromining to be profitable, protect the environment from the destruction of traditional open pit mining, and allow use of soils (low grade ores) which are not economic for the mining industry. In practice nickel has the greatest promise for commercial phytomining because of the existence of extreme nickel accumulating plant species (hypernickelophores which accumulate over 1% Ni on a dry matter basis in harvestable plant shoots), and extensive Ni rich ultramafic soils in many nations. Alyssum species were domesticated for phytomining and improved cultivars were bred for higher annual Ni accumulation and yield, while for other tropical nations species such as Phyllanthus will need to be domesticated and improved for commercial use. Besides development of best agronomic practices (fertilization; harvest dates; coppicing) to obtain high annual yields of Ni in the biomass, methods were developed to recover Ni from the biomass and generate several Ni salts or Ni metal with high purity because the plants remove Ni from the soil matrix into the plant nutrient matrix which does not interfere with recovery of the Ni for commercial use. With the imminent expiration of the patents on Ni phytomining, the economic opportunity offered by phytomining is available for commercialization on present mine sites, mine wastes, smelter contaminated soils, and the extensive sub-economic ultramafic soils. In locations where soils are below present ore grade Ni levels, agromining by small farmers will offer a high value cropping opportunity as well as over time, improving the soil fertility for production of food crops on otherwise infertile ultramafic soil materials.