Fertiliser on the rocks

Manure or compost are cheaper alternatives to commercial fertilisers, but you might be sitting on top of another one in your land, just waiting to be activated: inorganic phosphorous rock. Using the rock is in itself not new. In factories all around the world, phosphate rock is processed chemically (with sulphuric acid, for instance) to make the phosphate soluble for use as crop fertiliser. In the mid-1990s, researchers from Zimbabwe s Institute of Mining Research and Canada s University of Guelph in developed a small device that mixes phosphorous rock with triple super-phosphate fertiliser into clean and easy-to-handle pellets. Once the pellets are applied to the soil and watered, a chemical reaction releases the phosphate into the soil. The device is easy to make and is catching on fast in Kenya and Uganda where local artisans produce it for around US$200. With support from the agroforestry centre ICRAF, Canada s IDRC, the Rockefeller Foundation and the Africa 2000 programme, the technology is now being replicated in Burkina Faso, Mali and Senegal. P van Straaten, Department of Land Resource Science University of Guelph, Guelph, Ontario, Canada N1G 2W1 Fax: +1 519 824 57 30 Email: pvanstra@lrs.uoguelph.caManure or compost are cheaper alternatives to commercial fertilisers, but you might be sitting on top of another one in your land, just waiting to be activated: inorganic phosphorous rock.Using the rock is in itself not new. In factories all around..