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Science

Fertilizers and crop yield

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Fertilisers contain minerals such as nitrogen, potassium and phosphorus, which help plants to grow. Fertilisers increase crop yields but cause the problem of 'eutrophication' when they're washed by rainwater into rivers and lakes. Most chemical fertilisers are made by the reaction of an acid with an alkali.

Fertilisers

Fertilisers make crops grow faster and bigger so that crop yields are increased. They're minerals, which must first dissolve in water so that plants can absorb them through their roots.

Fertilisers provide plants with the essential chemical elements needed for growth particularly nitrogen, phosphorus and potassium. The proportions of these elements in a fertiliser are often shown as N:P:K = 15:30:15.

The name or formula of a compound often suggests which elements are provided by a particular fertiliser.

Examples of fertilisers, their formula and the essential elements

FertiliserFormulaEssential elements
Ammonium nitrateNH4NO3nitrogen
Ammonium phosphate(NH4)3PO4nitrogen and phosphorus
Ammonium sulfate(NH4)2SO4nitrogen
Urea(NH2)2COnitrogen
Potassium nitrateKNO3potassium and nitrogen

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