Fertilizer

Fertilizers or fertilisers are compounds given to plants with the intention of promoting growth; they are usually applied either via the soil, for uptake by plant roots, or by foliar spraying, for uptake through leaves.

Environmental effects of fertilizer use

Over-application of fertilizers, or application at a time when the ground is waterlogged or the crop is not able to use the fertilizer, can lead to run-off in groundwater. This can enrich lakes and streams in a process called eutrophication and lead to algal blooms. It is possible to over-apply organic fertilizers as well, but their nutrient content, solubility, and release rate are typically lower. The problem is endemic, however, and is primarily associated with the use of artificial fertilizers, if only due to the massive quantities involved. Their high solubilities are also a factor.

Related Topics:
Run-off - Groundwater - Eutrophication - Algal blooms

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Storage and application of fertilizers in particular weather or soil conditions can also cause emissions of the greenhouse gas nitrous oxide (N2O). Ammonia gas (NH3) may be emitted following application of manure or slurry or due to inorganic fertilizers (to a lesser extent unless ammonia itself is used directly). Besides suppling nitrogen, ammonia can increase soil acidity (lower pH, or "souring").

Related Topics:
Greenhouse gas - Nitrous oxide - Ammonia - Acidity - PH

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For these reasons, it is recommended that knowledge of the nutrient content of the soil and nutrient requirements of the crop are carefully balanced with application of nutrients in organic and inorganic fertiliser. This process is called nutrient budgeting. By doing this the farmer will avoid wasting fertiliser and also avoid the cost of avoiding or cleaning up pollution.

Related Topics:
Nutrient budgeting - Pollution

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