Information sheet: Pesticides and fertilisers
Age: KS3, KS4
Discusses how organic systems use alternatives to the chemical controls of non-organic farming by increasing biodiversity and soil fertilty.
Pesticides are chemical substances used to kill or control pests. They include insecticides (for insect pests), fungicides (for mould and fungi that cause plant diseases), herbicides (for weeds), molluscicides (for snails and slugs) and rodenticides (for rats and mice). Currently there are 3403 pesticide products meeting legislative requirements for use in the UK. Nitrogen is an essential chemical element that plants need for photosynthesis. All farmers apply nitrogen and other nutrients to improve their crop yields – either as artificial chemical fertiliser or livestock manures. However, sometimes there is more nitrogen than the soil micro-organisms and plants can take up and some of this nitrogen can be washed into streams or rivers. This pollution can result in the death of aquatic plants and animals. Unlike conventional farming, organic systems use only a very limited number of pesticides and do not use artifical chemical fertilisers.