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Fluid Journal : Fall 2011
11 The Fluid Journal Fall 2011 the aqueous phase, so this led him to a series of experiments to determine the effect on plants of a range of dissolved substances, including many inorganic compounds derived from mineral sources. Although in the 17th century Sir Kenelm Digby had watered barley with a dilute solution of nitre and reported luxuriant growth, he did not appear to have appreciated its potential significance. Consequently, Davy tried on both grass and corn the effect of a range of solutions containing sodium, potassium, and ammonia as sulphates, nitrates, carbonates, chlorides, and acetates. He found that in all cases: “...when the quantity of salt equaled one thirtieth part of the weight of water, the effects were injurious, but least so in the instances of carbonate, sulphate, and muriate of ammonia.” Further dilution by a factor of ten made all the difference and he concluded: “Plants watered with the solutions of sulphates grew just in the same manner as similar plants watered with rain water. Those acted on by the solution of nitre, acetate, and super-carbonate of potassa, and muriate of ammonia grew rather better. Those treated with the solution of carbonate of ammonia grew most luxuriantly of all.” Davy was somewhat puzzled by the results from ammonium nitrate solution as the growth was similar to that of plants treated with rainwater, but when he found that the solution was very acidic he concluded that the free acidity may have interfered with the result. Subsequently, in 1801, he scaled up the more successful of his experiments when he was able to assist growth in a field of wheat by applying a dilute solution of ammonium acetate. He also made the point that soot, long known for its fertilizing properties, contained ammonium salts and deduced that the liquor arising as a byproduct from the destructive distillation of coal could be an abundant source of ammonia that could be used for agricultural purposes. Significant quantities of this so-called gas liquor were applied on a local basis. However, it was many decades before it was officially recognized as a nitrogenous fertilizer. Gifted insight Humphry Davy was an extraordinary individual with intuitive experimental skills, coupled with a flair for communicating his findings to his audiences in his Royal Institution lectures and elsewhere. Sir John Russell considered that one of Davy’s major contributions was to establish Agricultural Science as a coherent subject. Russell claimed that Davy’s “Elements of Agricultural Chemistry” reigned as the standard text of its field for over 50 years and that its contents were cited in 1840 by Justus Liebig in his well-known work in the same field. It was my privilege in 1974 to draw attention to Davy’s remarkable insight into the way nutrients in fluid form were taken up by crops and the crucial role of nutrient concentration in optimizing crop response. It is further my privilege to be able to author this article in celebration of the 200th Anniversary of Davy’s seminal work that contributed so much to the world of fluid fertilizers as we know it today. Derek Palgrave, author, joined J.W. Chafer, Ltd. of Doncaster, England, in 1964 as its chief chemist and technical director. He is now involved in a program of public lecturing on a wide range of topics, including science and technology. Essential crop functions are dependent on complex interactions between NPK and micronutrients. The correct amount of some nutrients - and not enough of others – can starve crops and reduce yield potential. Remember the Law of the Minimum: “Yields are limited by the nutrient in shortest supply.” If your goal is to improve fertilizer efficiency – by growing more with less to reduce costs and protect the environment – don’t overlook the power of micronutrients. Micronutrients a necessity for higher yields Micronutrient Manufacturers Association (MMA) PO Box 8563 · Woodland, CA 95776 · 916.539.4107 www.micronutrientfertilizer.com The mission of the MMA is to promote and educate agri-dealers and growers on the importance of using micronutrients to acheive maximum economic yields.