. Discovery. Science. DISCOVERY 123 there is no question that it would serve as a source of nitrogen for all crops. Unfortunately the process requires considerable electric power. A second method gives cyanamide. In this case calciuna carbide is first formed by heating lime and carbon in an electric furnace ; the carbide is then further heated in an atmosphere of nitrogen, when calcium cyanamide is formed. This is not itself a fertiliser, but it rapidly breaks down in the soil to give urea, which further decomposes to ammonia. This process requires less power than the other, but unfortunately
. Discovery. Science. DISCOVERY 123 there is no question that it would serve as a source of nitrogen for all crops. Unfortunately the process requires considerable electric power. A second method gives cyanamide. In this case calciuna carbide is first formed by heating lime and carbon in an electric furnace ; the carbide is then further heated in an atmosphere of nitrogen, when calcium cyanamide is formed. This is not itself a fertiliser, but it rapidly breaks down in the soil to give urea, which further decomposes to ammonia. This process requires less power than the other, but unfortunately cyanamide has disadvantages as manure : it is dusty and unpleasant in use ; is apt to contain a substance toxic to plants, and does not invariably give seasons there is little, if anything, to choose between them ; in drier conditions the cliloride is somewhat less effective than the sulphate. The chlorine ion bears possibilities of harmful influence on plants ; when its concentration exceeds a certain value, both the yield and the quality of the crop suffer. These technical difficulties, however, are not insuperable, and the catalytic process remains as an effective contributor to the supply of nitrogen fertilisers. Prior to the war the consumption of nitrogen fer- tilisers had doubled in ten years and the output had practically kept pace: since the war there has been serious dislocation in agriculture involving reduced consumption, but the productive capacity had more. â ^'»: 5f;(jf« .V''-J',';:''^?;''6£J;^'; â fc â .'Jixft.^ . Showing plots on which fertilisers are tested. the increased crop expected. In Central Europe (Switzerland, Germany, etc.) there are large cyanamide plants put up for the purposes of the war, but which could not without serious financial disturbance be scrapped ; ver}' vigorous attempts are therefore being made to overcome the disadvantages of this material. It is too early to say what results may be attained. It has been proposed to c
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