Phosphorus, abundance reserves

Despite its relatively late discovery, phosphorus is the eleventh most abundant element in Earth s crustal rock. It has been estimated that world reserves of phosphate rock are sufficient to last for several hundred years. Virtually all phosphorus deposits contain apatite, whose general formula is Caj (P04)3 X, where X — OH, or Cl. Fluoroapatite is the least soluble, hence most abundant, of the three apatite minerals. Phosphorus Is found in aqueous systems as HPOq and H2 PO4 ions. In biological organisms, phosphorus is a component of nucleic acids and energy-shuttling molecules such as ATP. 

Phosphorus and K reserves appear adequate for several centuries to come, but present N fertilizer technology is dependent upon a cheap and abundant supply of natural gas as a source of H and process heat. 

World phosphorus reserves. Phosphorus constitutes 0.10 to 0.12% of the earth s crust and lies twelfth in order of abundance among chemical elements. 

Starch is a glucan and is present in many plants as a reserve carbohydrate. It is most abundant in seeds, fruits, tubers and roots. Starch occurs naturally in the form of granules, whose size and shape vary in different plants. The granules are built up in concentric layers, and although glucan is the main component of the granules they also contain minor constituents such as protein, fatty acids and phosphorus compounds, which may influence their properties. 

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