Part 4c. Methods of increasing food production and improving sustainability

4c. The use of various agrichemicals and pharmaceutical products to increase food production

Doc Brown's Biology exam study revision notes

There are various sections to work through, after 1 they can be read and studied in any order.

Sub-index of notes on increasing food production

Index of notes on ALL aspects of food production

re-edit 11/05/2023


4(c) An assortment of agrichemical and pharmaceutical products to increase yields

Synthetic inorganic fertilisers are dealt with in Part 4b.

You can control disease and insect damage without using GM crops by the use of herbicides and pesticides, but there are advantages and disadvantages.

Pesticides are chemical compounds designed to be toxic to any living thing that attacks crops and reducing damage to crops and increase yields by utilising pest control methods.

'Pests' include microorganisms-pathogens including bacteria and fungi, a variety of insects and mammals like rats.

Insecticides kill insects that may eat or damage the crops, reducing yields.

Herbicides kill weeds that compete with the crop for water, light and minerals in the soil.

Fungicides kill any fungus that damage the crop, reducing quality and yield.

The pest control is usually sprayed onto crops to kill the 'pest', but they are often toxic to humans and other animals that are not considered as pests e.g. bees, ladybirds and birds of prey are affected - anything higher in a food chain is affected if their food supply is damaged.

The minimum 'safe level' of pesticide is applied to minimise contamination of toxic chemicals accumulating in the local ecosystem food chains.

Insecticides kill insects, fungicides kill fungi, herbicides kill weeds.

All of these increase crop yields and are extensively used for intensive farming methods, but not without unwanted consequences.

Again, as with fertilisers, they are not to be overused and unfortunately organisms like insects and bacteria can undergo mutations and develop 'strains' resistant to e.g. a particular fungicide or insecticide product.

This is happening all the time, so new costly products have to be developed all the time.

As well as treating plant crops with anti-pest agents, you can vaccinate livestock against certain diseases.

Antibiotics can be given to animals to protect against bacterial pathogens - but this means antibiotics have entered the food chain, so we may consume them - not good for our immune system?

Plant growth hormones are applied to crops to encourage growth and increase crop yields.

You can also control when crops ripen and harvesting - as far as I know, these methods are not controversial.

See Hormone control of plant growth and uses of plant hormones  gcse biology notes

Growth hormones are also used in cattle rearing as well as feeding the animals supplementary high protein foods.

Animals may be deliberately confined in huge cattle sheds to minimise movement, so less energy is wasted and more used for growth - so hormones, protein food and confinement all increase the energy transfer to the cattle.

BUT, the ethics of these methods is being questioned and there are biological consequences too.

The spread of a disease is rapid because of the close confinement of the animals.

Cattle have been bread to produce greater yields of beef meat or greater volumes of milk, but such animals and not as genetically healthy as their predecessors e.g. lameness in milk cows.

Is it fair to not allow the animals to move naturally freely beyond their 'cages'?

The unethical nature of some animal transportation and slaughtering.

When cattle are given hormones to increase milk and meat yields - these hormones are entering the food chain to reach us and out into the environment via faeces!


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