© C. Aholou-IFA
February 2013
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nutrients or provide nutrients that are not needed. Thus, if SoilDoc shows P to be sufficient, the cost of normal application of DAP can be saved (about US$100 per hectare). Or if, for example, SoilDoc shows that sulphur is needed and US$ 20 worth of gypsum gives 1000 kg extra maize worth US$ 500 where only urea and DAP are applied, the benefit may be about US$ 480 per hectare. The cost of running a suite of analyses on a soil sample with the SoilDoc kit is likely to be about US $1-2 including kit amortization costs, but not farmer or extension worker labour costs. Use of Soil Doc would enhance, not detract from, the extension worker's educational/outreach mission and interaction with farmers.
How will the kit help smallholder agriculture? Many farmers either lack information about soil constraints in their fields or are following government blanket recommendations. Africa is beginning to emerge from a static smallholder agriculture where cereal yields have remained at the same level of around 1 tonne per hectare (or the equivalent in other crops and livestock products) for the past 50 years. Government programmes have employed incentives or credit for fertilizers and high-yielding seeds, doubling or tripling crop yields at local or national scale in several parts of Africa. SoilDoc allows a more targeted approach that uses resources more effectively to move yields of 2-3 tonnes per hectare of maize and eventually to 5-7 tonnes per hectare. This includes tailored fertilizer recommendations appropriate to particular soil and farming/cropping systems. Such tailored recommendations, developed by SoilDoc or by central laboratories, would support farmers in increasing their agricultural productivity in a way that is more efficient than currently possible.
Contact Greg Fienhold Earth Institute, Columbia University, USA gfienhold@ei.columbia.edu
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We’re not running out of fertilizer Or he could have consulted the materials put out by the International Fertilizer Industry Association, whose members include many of the world’s most prominent fertilizer producers, traders, and shippers. The association (emphasis in the original) “does not believe that peak phosphorus is a pressing issue, or that phosphate rock depletion is imminent. Nevertheless, it believes that efforts to minimize phosphorus losses to the environment and optimize phosphorus use should be encouraged.’’ And that is precisely as it should be, because wasteful use of all kinds of fertilizers is common and optimizing the applications brings substantial monetary and environmental rewards (phosphates are a major cause of aquatic eutrophication, their worst effects are persistent dead zones in many coastal areas around the world). Larger gains in reducing phosphate applications could be made by moderating typical per capita meat consumption, and a great amount of the element can be recovered from waste. In all Western countries, most fertilizers are now applied to feed not food crops, and hence moderating the current high rates of meat consumption (commonly in excess of 100 kg per capita) would reduce the amount of needed fertilizer. Such cuts would also have environmental and health benefits. An even more important option – especially given the facts that much of modern meat, milk, and egg production is done in a concentrated manner, and that half of the world’s population lives in cities – is now available thanks to advances in phosphorus reuse from manures and municipal wastes. Grantham could have talked to many experts in this flourishing field, or could have simply consulted the SCOPE Newsletter, which reports,
several times every year, the latest scientific and commercial achievements regarding phosphorus recovery. In the latest issue of this newsletter he would have also learned that the world has, at the current rate of consumption, about 600 years of minable potassium reserves. Grantham cannot dismiss all of this as just usual propaganda put out by the fertilizer industry. That a financier and asset manager – whose expertise does not include resource geology, soil science, plant science, or agronomy – comes to “only one conclusion,’’ namely that the use of fertilizers “must be drastically reduced in the next 20-40 years or we will begin to starve,” is as wrong as it is understandable. Clearly, he was after sensational headlines and, indeed, in his column he implores scientists to engage in “overstatement’’ and to be arrested (if necessary) in order to call attention to the imminent perils he describes. That the world’s leading scientific journal prints such tabloid talk is harder to comprehend. Do we not have science precisely in order to provide us with the best available evidence so we can understand the real challenges and make well-informed decisions to pursue the most responsible and the most effective solutions? Vaclav Smil does interdisciplinary research in the fields of energy, environmental and population change, food production and nutrition, technical innovation, risk assessment, and public policy. This essay was originally published at The American (www.american. com/archive/2012/december/jeremygrantham-starving-for-facts). Smil is the author of “The Manufacturing of Decline” in Breakthrough Journal Issue 1 (thebreakthrough.org/index.php/journal/past-issues/issue-1/).
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