|Better Farming Series 06 - The Soil: How to Improve the Soil (FAO - INADES, 1976, 29 p.)|
|Plan of work|
Manure, compost, green manure.
· Read pages 4 to 8.
· Do they make manure and compost where you live?
· To understand what manure does look at Booklet No. 4, page 22.
· Do you know why you should both grow crops and raise animals?
· Read pages 4 to 14.
· Study pages 4 to 8 about manure, compost and green manure once again.
· It is very important to understand clearly what fertilizers do, and to know how to read the label on a sack of fertilizer.
· How do they use fertilizers where you live?
· Read pages 15 to 20.
· Do they use irrigation where you live?
· Can they use irrigation?
· What is a less tiring way of lifting water?
· Can they make dams where you live?
· Do you fully understand what water does in the soil? Look at Booklet No. 4, page 29.
· Read pages 21 to 28.
· Does grubbing trees make the harvests better?
· How do they clear the land where you live?
· Look again at Booklet No, 5, page 20 where it deals with brush fires.
You must understand that brush fires are bad.
· Reread the whole course.
· Answer the question paper.
HOW TO IMPROVE THE SOIL .
Many soils are poor and do not yield a good harvest.
A modern farmer improves his soil.
· He gives it mineral salts (see Booklet No. 1, page 19);
· He improves its structure (see Booklet No. 4, page 24) by giving it humus.
Many soils are difficult to work.
· The soil is too dry or too wet.
The farmer improves the soil by irrigation and
· The land is full of trees.
The farmer grubs the trees.
HOW TO IMPROVE SOIL FERTILITY
Plants grow by taking mineral salts from the soil.
A plant that finds plenty of mineral salts in the soil grows quickly.
You must give the soil mineral salts. Manure, compost, fertilizers all add mineral salts to the soil.
You can get manure (dung) when you keep animals, such as cows, oxen, sheep, goats, donkeys, pigs.
To get manure, a farmer should both grow crops and raise animals.
· Making manure
To make manure, put dry herbage and straw (stems of rice, maize, millet) to rot with animal droppings.
The microbes (see Booklet No. 4, pages 22 and 35) in the animal droppings decompose the leaves and straw.
This makes manure.
Manure in the soil makes humus (see Booklet No. 4, page 22).
A good farmer does not let his animals run about the bush.
You should put them in a paddock with a shelter, a cattle shed.
In the shed put leaves and straw. The animals sleep on it, and make their droppings. With the droppings, the straw rots. You must add straw often. Then you have Good manure.
The shelter protects the animals.
It also prevents rain from making the manure too wet.
It prevents the sun from drying the manure. If it gets dry it does not rot.
When you have no animals, and no manure, you can make compost.
Compost is a mixture of plants, stems of millet and maize, etc., refuse from the house, remains of food such as vegetables and fruit, which all rot together.
· Making compost
Dig a hole.
At the bottom of the hole put a lot of big pebbles and stones, so that too much water will not stand in the hole.
Throw into the hole all the household refuse, weeds and plants you have cut down, and the refuse from the harvest.
Water the heap to make it rot.
Like manure, the compost must not dry out.
So make the heap in the shade to shelter it from the sun.
· Using compost and manure
Take it to your field.
Spread it out well.
Mix it with the soil by turning over the soil either with a hoe or a plough.
Manure and compost contain mineral salts, which enrich the soil; humus, which improves the soil structure.
When you do not have enough manure or compost, you can enrich
the soil all the same.
You do it by sowing plants.
When they have grown to a good size, cut them down, mix them with the soil by turning it over with a hoe or plough.
The plants rot and make the soil richer. These plants are called green manure.
For example, you can sow Pueraria, and plough it in when the
seeds begin to form.
Green manures do not yield any harvest.
They are plants which are grown and then put into the soil. They enrich the soil with humus and make possible better harvests afterwards.
Manure, compost and green manure require no money.
They require only work.
· Fertilizers give the soil mineral salts (see Booklet No. 1, page 19). With fertilizers, harvests are better.
· But fertilizers are
A farmer only buys fertilizers if the increase in his harvest will pay for the fertilizers.
A farmer only buys fertilizers if they will earn him money.
· It is useless to apply fertilizers if your farming work is not well done.
· If you do not control erosion, the good earth with the fertilizers is carried away.
· If you have tilled the soil badly, plant roots grow badly.
· If you have sowed late, the plants will be late and will not grow enough before the dry season.
· If you do not get rid of the weeds, the fertilizer will chiefly benefit the weeds.
· If you do not control insects and diseases the harvest will be no better and the fertilizer will be wasted.
Apply fertilizer only when all your farming jobs are well done.
They contain nitrogen.
Nitrogen makes leaves grow and gives them a good green colour.
In the leaves raw sap is changed into elaborated sap (see Booklet No. 2, page 20).
Nitrogen helps the formation of elaborated sap.
And harvests are better.
The chief nitrogen fertilizers are:
· sulphate of ammonia,
If you see the letter N on the label of a sack of fertilizer, that means nitrogen.
They contain phosphorus in the form of phosphorus
Phosphorus makes the plant stems strong.
It also helps the formation of flowers and fruits.
It makes better grains and fruits.
The chief phosphorus fertilizers are:
· natural phosphates: In Africa there are phosphate mines at Taiba and Thi(Senegal and at KpemTogo).
If you see the letter P on the label of a sack of fertilizer, that means phosphorus.
They contain potassium.
Potassium helps plants to withstand drought and diseases.
It also helps the plant to build up food reserves (see Booklet No. 1, page 241, so that the roots become fatter (cassava), and seeds are more plentiful and finer.
The chief potassium fertilizers are:
· natural potassium: In Africa
there is a big potassium mine at Holle (Congo).
· potassium chloride,
· potassium sulphate.
If you see the letter K on the label of a sack of fertilizer, that means potassium.
· Compound fertilizers
The fertilizers you buy are not all the same.
Those which contain only nitrogen or potassium or phosphorus are called straight fertilizers.
Others are mixed.
They are called compound fertilizers.
Compound fertilizers contain different quantities of nitrogen, phosphorus, potassium.
You may have seen labels like this on sacks of fertilizer. The first Figure shows
COMPOUND the quantity of nitrogen (N)
FERTILIZER in 100 kilogrammes
13- 10- 15 of thisfertilizer.
In this case 13 kg.
The second Figure shows the quantity of phosphorus (P) in 100 kilogrammes of this fertilizer. In this case 10 kg.
The third Figure shows the quantity of potassium (K ) in 100 kilogrammes of this fertilizer. In this case 15 kg.
We say this fertilizer has a 13- 10- 15 content.
To find the amount of nitrogen, phosphorus and potassium contained in a sack of fertilizer, we must multiply the fertilizer content by the weight of the sack and divide the result by 100, thus: content X weight of sack 100
In a 50 kg sack of 13- 10- 15 fertilizer there is: nitrogen 3 X 50 = 6.5 kg
10 X 50/100 = 5.0 kg
15 X 50/100 = 7.5 kg
· Apply by hand.
You can apply the fertilizer by throwing it broadcast.
It falls all over the place.
It is better to apply fertilizer along the plant rows.
With a stick make a line in the earth a few centimetres away from the row of plants.
Put the fertilizer in this line and cover it with earth.
Or else, put the fertilizer at the foot of the plants just
before you earth them up
In tree plantations such as palms, coffee, cocoa, put the fertilizer in a circle 1 or 2 metres from the tree trunk.
The feeding roots of the tree are at a distance of 1 or 2 metres from the trunk.
Spread fertilizer round the trunk at a distance of 1-2 m.
· Apply with a machine.
This machine is called a fertilizer distributor.
With some mechanical seed drills you can sow and spread fertilizer at the same time.
SOME PRACTICAL ADVICE
· Do not put fertilizer on the stems and leaves of plants. The fertilizer may burn them.
· Fertilizer is costly.
Do not put just any fertilizer on any crop. Different plants
have different needs.
Ask the extension worker for advice.
Choose the right fertilizer.
· All fertilizers are not the same.
Fertilizers contain different amounts of the mineral salts (N,
Get to know the quality of fertilizers.