Foods that give nitrogen must be chosen
To live, plants take out of the soil mineral salts (see Booklet
No. 6, page 10) which contain nitrogen, phosphorus, potassium.
Different plants have different needs (see Booklet No. 6, page
All plants do not have the same need of the same amount of
Animals too have different needs.
· They need food that gives them
strength and energy; these are called energy foods.
For example: maize, cassava.
· They need food to make their
muscles and their meat. These are nitrogenous foods, foods that contain
For example: oil cake.
Modern farmers put fertilizers on their fields. Fertilizers
complete the plants' food.
Modern farmers who raise animals also complete the food of their
animals by giving them, as well as energy foods, foods that contain nitrogen.
These foods are called feed supplements.
With nitrogenous foods an animal grows better and produces
plenty of meat.
Food rich in nitrogen is called a protein- rich food.
Feed supplements, like fertilizers (see Booklet No. 6, page 14),
A farmer must choose the right feed supplement.
Many experiments have made it possible to work out the amount of
digestible proteins (nitrogen) which each food contains.
The foods which are richest in nitrogen are oil cake, meat meal
and fish meal, and milk.
The amount of digestible protein
(nitrogen) in 1 kg of food
In the same way as for fodder or feed units, tables have been
made which show the amount of digestible protein in each food.
Other tables have been made which show the protein needs of each
kind of animal.
Animals make good use of energy foods and body- building foods
if they are given mineral salts and clean water at the same