BETTER FARMING SERIES

Twenty-three titles have been published in this series, designed as handbooks for intermediate level agricultural education and training. They may be purchased as a set or as individual documents.

1.  The way to work. The living plant

2.  The plant - the root

3.  The plant - the stem

4.  The plant - the leaf

5.  The plant - the flower

6.  The soil - man and the soil

7.  The soil - how the soil is made up

8.  The soil - the living soil - working the soil

9.  The soil - working the soil (continued)

10.  The soil - conserving the soil - improving the soil

11.  Animal husbandry - introduction

12.  Animal husbandry - feeding animals

13.  Animal husbandry - looking after animals - how cattle reproduce

14.  Animal husbandry - what cattle produce

15.  Keeping chickens

16.  Food crops

17.  Market gardening

18.  The oil palm

19.  Groundnuts

20.  Upland rice

21.  Wet paddy or swamp rice

22.  Cocoa

23.  Coffee

Better Farming Series    16

Food Crops

Published by arrangement with the Institut africain pour le développement économique et social

FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS

Rome 1970

© French edition, Institut africain pour le développement économique et social (INADES) 1967

© English edition, FAO 1970

Contents

1. Preface

2. Outline Of Course

3. What is a food crop?

1. Why we must produce more

2. Why we must sell more

3. How to increase the yield of food crops

4. How to improve farm work

1. Preparing the soil: tilling

2. What to do to prevent erosion

5. How to improve plants

1. Seeds

2. Sowing

3. Cultivating

4. Improving the soil to keep it fertile

5. Crop rotation

6. Organic manure and chemical fertilizers

6. Growing yams

1. Yam plants have tubers

2. What do yam tubers need for good growth?

3. How to plant yams

4. How to look after yams

5. Harvesting and storing

7. Growing cassava

1. Cassava is a vigorous plant

2. How to prepare the soil

3. How to plant cassava

4. How to look after cassava

5. Harvesting

8. Growing sorghum

1. Why is sorghum grown?

2. Where is sorghum grown?

3. How to prepare the soil

4. How to sow

5. How to look after sorghum

6. Harvesting

7. Sorghum as animal feed

9. Growing millet

10. Growing maize

1. Why maize is grown

2. Traditional maize growing

3. How to increase maize yield?

4. Choosing the seeds

5. Preparing the soil

6. Manure and chemical fertilizers

7. Harvesting and storing

11. Suggested question paper

PREFACE

This manual is a translation and adaptation of “Les cultures vivrières,” published by the Agri-Service-Afrique of the Institut africain pour le développement économique et social (INADES), and forms part of a series of 23 booklets. Grateful acknowledgement is made to the publishers for making available this text, which it is hoped will find widespread use at the intermediate level of agricultural education and training in English-speaking countries.

It should be noted that the original texts were prepared for an African environment and this is naturally reflected in the English version. However, it is expected that many of the manuals of the series — a list of which will be found on the inside front cover — will also be of value for training in many other parts of the world. Adaptations can be made to the text where necessary owing to different climatic and ecological conditions.

Applications for permission to issue this manual in other languages are welcomed. Such applications should be addressed to: Director, Publications Division, Food and Agriculture Organization of the United Nations, Via delle Terme di Caracalla, 00100 Rome, Italy.

The cover illustrations were prepared by Asun Balzola.

OUTLINE OF COURSE

• What is a food crop?

Why we must produce more

Why we must sell more

How to increase the yield of food crops

• How to improve farm work

Preparing the soil: tilling

What to do to prevent erosion

• How to improve plants

Seeds

Sowing

Cultivating

Improving the soil to keep it fertile

Crop rotation

Organic manure and chemical fertilizers

• Growing yams

Yam plants have tubers

What do yam tubers need for good growth?

How to plant yams

How to look after yams

Harvesting and storing

• Growing cassava

Cassava is a vigorous plant

How to prepare the soil

How to plant cassava

How to look after cassava

Harvesting

• Growing sorghum

Why is sorghum grown?

Where is sorghum grown?

How to prepare the soil

How to sow

How to look after sorghum

Harvesting

Sorghum as animal feed

• Growing millet

• Growing maize

Why maize is grown

Traditional maize growing

How to increase maize yield?

Choosing the seeds

Preparing the soil

Manure and chemical fertilizers

Harvesting and storing

• Suggested question paper

WHAT IS A FOOD CROP?

1. People need to eat in order to live.

They pick and gather fruits, leaves, and seeds from trees or plants. They hunt and fish in order to get meat and fish.

But nowadays hunting, fishing and picking plants do not provide enough food to feed all the people.

People must grow crops of yams, cassava, cocoyams, sweet potatoes, rice, maize, groundnuts.

These crops are called food crops.

In other booklets, we have studied how to grow rice and groundnuts.

In certain regions, rice and groundnuts are grown mainly for sale.

In this booklet, we shall study the crops which in many parts of the world are the most important for feeding people; yams, cassava, sorghum, millet and maize.

Why must we produce more and sell more?

How can we improve the growing of food crops?

WHY WE MUST PRODUCE MORE

2. There are more people than in the past.

Fewer children die.

Men and women live longer.

We must produce more food to feed more people.

Many people go to live in towns. All these men and women do not farm the land; they buy their food.

Even in the villages, some men and women have new jobs, like teachers or nurses, and they do not farm the land.

Farmers have to produce food for selling to all the people in the towns and villages who do not grow any food.

Farmers have to produce more food. But often there are no new fields near the village to be cultivated. In any case, with traditional tools farmers cannot work larger fields; in the savanna the rainy season is often very short.

Farmers therefore must produce more on the same area — they must increase yields.

WHY WE MUST SELL MORE

3. People have new needs.

People in the villages have become used to having a bicycle, a motor-scooter, new materials for their clothes, a radio, a camera, and also roads, schools, dispensaries and hospitals.

To modernize the country needs money.

In order to get money, farmers must sell

• products for industry:

cotton for clothes materials, palm nuts and palm kernels, cocoa, coffee.

• products for food:

millet, rice, maize, yams, fruit and vegetables, beef, chickens.

4. But the crops which produce products for industry (industrial crops), take up large areas of land and cost the farmer a lot of time. So there is little land and little time left for food crops.

Farmers must therefore increase the yield of food crops.

With new methods and new implements, farmers can make better use of their land and their time.

HOW TO INCREASE THE YIELD OF FOOD CROPS

5. The yield of food crops can be increased by modern farming, which makes better use of the soil, plants and animals.

We shall study:

• how to improve farm work,

so that the plants grow better;

• how to improve the plants,

so that they produce more;

• how to improve the soil,

so that it remains fertile.

HOW TO IMPROVE FARM WORK

6. In traditional farming, the farmer clears the land.

To clear the land means removing herbage and cutting down the small trees.

But not all the plants are removed. Certain trees are left standing: trees that are too big, like the kapok tree or the baobab; and trees that provide food for people or animals, like the oil palm and the shea tree.

If the land is not well cleared, if too many trees and plants are left on the land, the crops must share their nourishment with the trees and plants still on the field. The yield of the crops will be less good.

If the land is well cleared, if few trees and plants are left on the field, the crops can use all the nourishment that is in the soil. The yields are better.

7. In modern farming, the farmer also removes the tree stumps.

When a tree is cut down, the tree stump and the roots still remain in the field.

Farm tools, such as the hoe or the plough, often get damaged and bent by big roots.

It is not possible to sow in rows and to get through the field with an animal-drawn hoe. Trees, roots and tree stumps prevent the use of animal power.

Trees and tree stumps go on taking nourishment out of the soil. The crop grows less well around the trees and tree stumps.

8. How to remove tree stumps

Trees can be uprooted with a tractor, or with tools such as a hoe or an axe.

Removing tree stumps is slow and tiring work.

Tree stumps must be removed several months before sowing, to make sure that sowing will not be late.

When the trees are uprooted, they have to be taken away from the field, or else burnt.

Once the tree stumps are removed, the work is done and need never be done again. The soil is now free, and it is easier to prepare it for cultivation.

PREPARING THE SOIL: TILLING

Tilling means turning the soil over.

9. Why tilling is needed

Tilling enables water and air to get right into the soil. Tilling loosens the soil.

In loose soil, seeds germinate easily, roots penetrate easily and tubers grow without trouble.

Tilling buries herbage in the soil: it cleans the soil. The herbage rots in the soil and makes humus.

If manure has been put on the soil, tilling works the manure into the soil.

Tilling is done at the beginning of the rainy season, just as soon as the tools can move the soil.

Like that, sowing and planting will not be late.

It is good to till deeply, but bad to till too deeply, because this may bring infertile earth to the surface.

10. Tilling tools

Tilling can be done with the hoe, the spade or the digging fork.

Nowadays, it is done with a plough drawn by donkeys or oxen.

Like that, the work is done better and more quickly, the soil is prepared better.

Sowing can be done at the right moment and it is possible to cultivate larger fields.

The plough

A simple plough is generally used.

A plough consists of a ploughshare, a mouldboard and two handles.

11. How to plough

Make a first furrow with the plough across the whole length of the field.

At the end of the field, turn.

Make a second furrow alongside the first.

The second strip of ploughed field joins the first. After that, keep turning around the double strip of ploughed field.

This is called conventional ploughing - the field is divided into ploughed lands separated by furrows.

12. Now the field is well ploughed.

Ploughing often does not leave the soil flat.

There are clods of earth.

These clods of earth are broken up with a harrow.

If you do not have a harrow, you can let an animal draw big branches over the field. The branches crush the clods.

WHAT TO DO TO PREVENT EROSION

13. If the field is on a slope, the rainwater may wash away the cultivable soil.

There are various ways of collecting water and keeping soil in place:

ditches

barrier strips

terracing

strip cropping

Ditches, barrier strips and strips of crops must all follow contour lines.

What is a contour line?

Look at the following two drawings.

• These lines follow the direction of the slope. Water flows very fast and carries away soil.

• These lines cut across the slope along the contour lines. Water and soil are held back.

A contour line is a line across the slope running always at the same height.

14. If the slope is very steep, it is a good thing to grow crops on terraces.

These are made by building little walls of earth or stone to hold the soil.

15. If the slope is steep, ditches are dug along the contour lines. The earth dug out from the ditch is piled up along the lower edge of the ditch and forms a big ridge.

The water runs along the ditches and does not carry the soil away.

16. If the slope is less steep, barrier strips are useful. A barrier strip is an uncultivated strip of land. Grass grows on this strip and checks the flow of water.

17. To check erosion, different crops should be grown between the barrier strips. For example, groundnuts, then a strip of fallow, then a strip of millet.

18. Root crops, like yams and cassava, need a lot of loose soil to make the roots large. If the layer of soil is not very thick, mounds or ridges should be made before planting.

If the field is on a slope, the ridges should follow the contour lines.

HOW TO IMPROVE PLANTS

SEEDS

19. Choosing seeds

To have good seeds, a farmer can either buy selected seeds, or choose the best seeds from his own crop.

Buying selected seeds

Research stations and extension services are always trying to find out what seeds are most suitable for the climate of each region, are most disease-resistant and give the best harvests.

These seeds cost a lot of money. It needs a plentiful harvest to pay for them. The harvest will be plentiful only if the farmer does all his work well.

20. Choosing seeds from the farmer's own crop.

The finest seeds of the crop should be chosen, for the good qualities of the seeds will be passed on to the plants that grow from the seeds.

Yams and cassava are not grown from seeds.

We shall explain later in this manual how to choose pieces of yam tubers and pieces of cassava stems for setting new plants.

For a good harvest, the seeds should be well stored and prepared before sowing.

21. Storing seeds.

Seeds should be dried before being put into the barn.

Seeds which are not quite dry may rot.

Seeds must be protected against insects and rats.

To protect seeds against insects, seeds are dressed with an insecticide.

To protect seeds against rats, the barn should be raised above ground.

22. Preparing seeds

Before sowing, the farmer should remove all the seeds that are broken, bitten, diseased or misshapen.

This seed may also be mixed with a dressing of fungicide and pesticide; see that all seeds are covered by it.

Dressed seeds are not eaten by insects. They do not rot. All the seeds will grow and few plants will be missing in the rows.

Sowing disinfected seeds makes for a good density: the yield will be better.

With traditional methods, farmers sow or plant in a haphazard manner. The density is not good and it is difficult to remove weeds.

SOWING

23. A farmer who wants to make progress, sows or plants in rows.

Sowing in rows means that the seedlings will all be at the same distance from each other.

It is easier to weed.

Animal power can be used, for the animal which draws the hoe can pass between the rows.

It is easier to give each plant the same amount of fertilizers.

On flat soil, the rows can be traced with a marker. If the field is on a slope, the rows must be traced along the contour lines.

For each crop we shall say what distance should be left between rows and between plants.

CULTIVATING

24. Cultivating means removing weeds

Weeds prevent the crop from growing well.

They take water out of the soil.

They take up the mineral salts of the soil or those that have been added by fertilizers.

By cultivating you break up the crust of dry earth which prevents air from getting into the soil.

Breaking up this dry crust also prevents the water from rising.

The soil remains moist.

Cultivating is done with a hand hoe or an animal-drawn hoe.

With an animal-drawn hoe the work is done more quickly, and cultivating can be done more often.

IMPROVING THE SOIL TO KEEP IT FERTILE

Crop rotation

25. Crop rotation means growing a different crop every year on the same field.

Why crop rotation is useful

Different plants take up different amounts of mineral salts from the soil; their needs are different

They also have different root systems, and therefore take up mineral salts from different depths of soil.

With crop rotation, the plants can use all the mineral salts of the soil.

The plants are nourished better and the soil does not get so poor.

For example:

A crop of groundnuts is followed by a crop of sorghum.

Groundnuts and sorghum do not have the same root system, and so they have different needs.

A crop of yams is followed by a crop of cotton.

Yams and cotton do not have the same root system and they have different needs.

A crop of rice is followed by a crop of groundnuts. Groundnuts and rice do not have the same root system and they have different needs.

Organic manure and chemical fertilizers

Manure and fertilizers add mineral salts to the soil.

26. To enable the plants to make good use of fertilizers, several things need to be done:

The soil must be well prepared.

In well prepared soil, roots develop well; they can take up all the mineral salts added by fertilizers and manure.

Sowing must be done at the right time.

Plants sown too late no longer have enough water to grow and use all the mineral salts.

Cultivation must be done often.

Weeds take up mineral salts. Weeds must be removed whenever they grow.

Crops must be rotated.

With good crop rotation, the different plants use all the mineral salts. The roots take up the mineral salts at different depths of soil.

Manure and fertilizers cost a lot of money. Their cost is not repaid by the harvest, and therefore they are not profitable if the farmer does not do all his work very well.

27. A farmer

who uses improved tilling methods,

who improves the plants,

who improves the soil,

is a modern farmer:

He needs to leave his fields fallow less long.

He can always grow crops on the same fields.

He cultivates larger fields.

He has more plentiful harvests.

He earns more money.

28. The farmer needs animals

so that he can cultivate larger fields, do the field work better and at the right time, and have manure for his crops.

GROWING YAMS

29. Where are yams grown?

To grow well, yams need a hot and moist climate and a lot of rain over a fairly long period. Yams cannot be grown in very dry regions or in regions where the sunlight is too strong.

For these reasons, yams are grown in Africa in the regions between the great dense forests and the dry treeless savanna.

It is best to plant yams in soil that is rich, deep and not too sandy.

30. What is the place of yams in crop rotation?

Yams are best planted at the beginning of the rotation, during the first year of cultivation, that is, as the first crop after clearing a field.

Yams need a lot of mineral salts. They can find these mineral salts in well tilled soil that has not yet borne any other crop.

31. There are short-season yams, which ripen in 6 months, and long-season yams, which ripen in 10 months.

YAM PLANTS HAVE TUBERS

32. A tuber is not a root

It is a part of the stem which thickens underground.

This part of the stem stores reserves.

These reserves could nourish the plant, so that it produces fruits and seeds.

But the plant is not left in the field long enough to produce seeds; the tubers are lifted and eaten by people.

• Certain varieties of yams may contain poison. We say they contain a toxic substance. But this toxic substance disappears when the yams are well washed and cooked.

33. The yam is a food containing mainly sugars; it is an energy food.

In order to live, eat, walk, keep in good health, resist the cold, heat and diseases, people need foods which give them strength.

These are called energy foods.

WHAT DO YAM TUBERS NEED FOR GOOD GROWTH?

34. A well-cleared soil

If you leave too many small plants and big trees on the field when you clear it, the roots of these plants and of these trees prevent the tubers growing to a good size.

They have not enough room to develop and not enough mineral salts for their nourishment.

35. A well-tilled soil

36. A soil with mounds

Plant yams in mounds. Make the mounds at the beginning of the rainy season.

Like that the soil is well stirred and stores water.

The tubers can grow well because they are surrounded and covered by a lot of earth.

HOW TO PLANT YAMS

37. Plant either pieces of tubers or small whole tubers. The piece of tuber or the whole tuber you plant should weigh about 250 grammes. This means that a sizeable part of the harvest must be put back into the ground.

If you plant a piece of a tuber, choose that part of the tuber where you see most growth buds.

38. If the layer of earth is thick enough and if you can make a deep tillage, it is not always necessary to make mounds. Ridges would be preferable.

In that case you can plant more tubers and your field will be more densely planted.

If the soil is not very deep, it is better to make mounds.

39. Plant your tubers at the beginning of the rainy season.

Then the yams can grow to a good size. They can use all the water of the rainy season.

• Push the tubers well into the soil.

When you have planted your tubers, cover them up with a lot of earth. Like that, the sun will not dry them out.

You can also cover the mounds with grass. Then the rain will not wash away the soil and the tubers.

• Support the plants by stakes.

Push sticks 2 or 3 metres high into the ground and tie lianas to these sticks. That way the stems and leaves of the plant can climb up around the sticks and lianas.

The stems and leaves grow better because they are fully exposed to the sun.

HOW TO LOOK AFTER YAMS

40. Weed - that is, remove weeds whenever they grow. When the rain spoils the mounds, remake them.

When the soil of the mounds gets too hard, break up the soil with the hoe, so that water and air can get in and nourish the tubers.

41. Harvesting

The date of harvesting differs according to the variety of yams you have planted.

Lift the tubers when the leaves on the stems begin to become yellow and start to dry.

Do not leave the yams in the ground too long, for the tubers then are less good to eat.

42. Storing

You can lose half your crop by bad storing.

Short-season varieties do not keep well. Eat them as soon as you lift them.

Long-season varieties can be stored for 5 or 6 months. But they must be protected against damp and rats. Store them under a roof, on dry ground or on boards supported by poles and make sure they are well aired.

Handle the seed tubers with great care. Do not allow shoots to grow on them while in storage.

Damaged tubers should always be removed, to avoid the spread of rot.

To reduce spoilage, turn the tubers in your store periodically.

GROWING CASSAVA

CASSAVA IS A VIGOROUS PLANT

43. It can grow even in very poor soil.

But cassava grows better in a moist climate, and in soil that is permeable and not too compact.

In a moist climate, where the rainy season is fairly long, the roots of the cassava plant grow faster.

If the soil is permeable, that is, if air and water circulate well in the soil, cassava does not rot.

If the soil is not too compact, the cassava roots grow to a bigger size.

44. It is easily propagated and productive.

Cassava is propagated by stem cuttings; pieces of stem are planted.

Cassava roots are not used for planting a new field; all the harvest can therefore be eaten or sold.

When very well grown cassava can yield a big crop — more than 50 tons per hectare.

45. It makes the soil very poor

On the fat cassava roots there are many small roots, and these are rather long. Cassava therefore takes up a lot of mineral salts from the soil.

A field which has yielded 50 tons of cassava afterwards contains hardly any mineral salts.

Unless the soil is given manure and fertilizers, it quickly becomes very poor.

For this reason, cassava is grown at the end of a crop rotation. Afterward the soil is left to rest, as fallow.

46. Cassava is not a rich food

Cassava contains energy foods (see paragraph 33), but very few that help to build up the body (proteins).

For example, a growing child needs proteins to make its bones and muscles big and strong.

A person who eats nothing but cassava is not living well, but needs to add proteins and vitamins to the meal; that is, fish, meat and green vegetables.

In some regions people also eat the cassava leaves.

47. Certain cassava varieties may contain poison. We say that they contain a toxic substance, and call them bitter cassava.

Others contain less toxic substance. We call them sweet cassava.

The toxic substance disappears when the cassava is well washed and cooked. Cassava must always be cooked, whether it is to be eaten by people or by animals; for example, chickens and pigs.

48. Cassava can be harvested 8 to 10 months after planting, if it is to be eaten at once.

This is the household use of cassava.

Cassava is left in the soil and harvested 18 to 20 months after planting, if it is to be used for the production of starch. Starch is a powder made from cassava, and it is used by factories to make tapioca.

This is the industrial use of cassava.

HOW TO PREPARE THE SOIL

49. Cassava roots need a loose soil to grow well.

If water and air circulate well in the soil, the roots are well nourished and do not rot because of dampness.

You can loosen the soil:

by tilling:

Till 20 to 25 centimetres deep. Like that the roots can get well into the soil.

by making mounds or ridges:

Make mounds or ridges after tilling, at the beginning of the rainy season.

Like that the soil is well stirred and stores water.

The roots have plenty of loose soil to grow in.

If you are applying manure and fertilizers, work them into the soil at the time of tilling.

Manuring may be profitable if you want to sell cassava to the tapioca factories; the bigger harvest can then repay the cost of manures.

HOW TO PLANT CASSAVA

50. Plant cuttings, that is, pieces of stem.

Choose the stems of the strongest plants

which are not diseased and have produced tubers.

Make bundles of stems

by tying together with a string or liana several of the stems you have chosen.

The bundles will keep well if you put them in a dry place.

Cut the stems into pieces 20-30 centimetres long.

Avoid cuttings from the top part of the plant.

Each of these pieces should have 4 to 6 growth buds. If the cutting has many growth buds, the cassava plant that grows from it will be better; it will have thicker stems.

Push into the soil the end of your piece of stem that grew nearer to the ground.

51. Plant the cuttings in mounds or ridges.

The time to plant is when the soil is very damp, after the beginning of the rainy season.

You can plant your cuttings straight or slanting.

Push them well into the earth, leaving only 2 or 3 buds above ground.

Press the earth down well around the cuttings. Like that, the new roots that develop will be well nourished by the soil.

Most often, the rows are at a distance of 1 to 1.5 metres, and the plants at a distance of 1 metre from each other in the row. With this spacing there are between 7 000 and 10 000 plants per hectare.

Density varies very much according to regions, soils and varieties.

If cassava is planted at a good density, the yield is large, the roots occupy all the soil and fewer weeds will grow, so that fewer cultivations have to be done.

Sometimes other crops are grown between the cassava plants — maize or beans, fonio or groundnuts. It is better not to grow several crops together.

HOW TO LOOK AFTER CASSAVA

Weeding is important

52. Weed the field when the cassava plants are 20 to 25 centimetres high, that is, 3 to 4 weeks after planting. Weed again after 1 to 2 months.

After that, the cassava plants are big enough to prevent weeds from growing.

When rain spoils the mounds, remake them.

When the soil of the mounds gets too hard, break the soil up with a hoe, so that water and air can get in and nourish the roots.

Harvesting

53. Cassava roots rot very quickly once they are lifted. They keep longer if they are left in the ground. When the cassava is too hard, make flour of it. When you lift the cassava roots, be very careful not to break them. You can use a lifting device made of two branches.

GROWING SORGHUM

WHY IS SORGHUM GROWN?

54. When sorghum is ripe, it fields grain.

This grain is a good food for people.

Like starchy roots, the grain of cereals is an energy food. But it is also a body-building food, for it contains proteins.

Grains are also a good food for animals. Animals fed on grains grow fast.

Working animals must be given grains which give them strength to work.

55. When sorghum is green, it can be fed to beef cattle.

The plants are cut when they are still green.

The animals transform the sorghum into milk, meat, and working energy.

56. Sorghum can also be used as green manure.

When tilling, the sorghum stems are worked into the soil.

They rot in the soil and produce humus.

Green manures improve the soil structure.

WHERE IS SORGHUM GROWN?

57. To grow well, sorghum needs a hot climate and a lot of sunshine.

When it begins to grow, it also needs water.

Later, when its roots are well developed, sorghum does not mind the drought.

Therefore, sorghum is grown in savanna country, where there is only one rainy season and much sun.

It is best to sow sorghum in soil that is not too clayey. Clay soils hold water and the sorghum roots may rot.

58. What is the place of sorghum in crop rotation?

It is best to sow sorghum after another crop, such as groundnuts or cotton.

Sorghum seed is small. To grow well, it needs a soil without large lumps, a fine tilth.

The previous crop improves the soil structure, leaves the soil with a finer tilth.

Sorghum is grown after groundnuts or cotton, and uses the rest of the mineral salts (fertilizers, manure) given to these industrial crops.

HOW TO PREPARE THE SOIL

59. Sorghum has a fibrous root system.

Sorghum needs a well-developed root system in order to take up enough nourishment and resist drought.

Sorghum roots are thin, they do not have the strength to penetrate into hard soil, soil that is too firm or cloddy.

Sorghum needs a fine soil, without clods, a loose soil.

After tilling, break up the clods with a harrow, or with big branches drawn across the field by an animal. If the layer of soil is not thick, make little mounds or ridges.

HOW TO SOW

60. First choose your seeds.

Keep the grains of the best spikes from your own crop.

Dry them, pick out the sound ones and keep them where they are well protected from insects and diseases.

You can also dress the seed with insecticides and fungicides before planting to avoid insect and fungal attack in the soil.

You can also buy seeds of improved varieties from research stations.

Certain varieties are harvested about 100 days after sowing. These varieties are sown in regions where the rainy season is short.

Other varieties are harvested 150 to 190 days after sowing. These varieties are sown in regions where the rainy season is longer.

Sow your sorghum seeds at the beginning of the rainy season. Sow them in rows, leaving 60-80 centimetres between the rows. Sow 2 seeds in each hole, leaving 10-15 centimetres between the holes. This gives an even spread of plants and good light interception.

Push the seeds 2 centimetres deep into the soil.

In some regions, sorghum is grown in fields which have first been flooded. Either the seeds are sown after the water has gone away, or the seeds are sown in a nursery and the young seedlings planted out into the field when the water has gone away.

HOW TO LOOK AFTER SORGHUM

61. Weed the field 15 days after sowing.

If the seeds in some holes have not grown, you can put in new seeds, or you can transplant some seedlings.

For transplanting, take out some seedlings from holes where all the seeds have come up.

Where all the seeds have come up in a hole, pull out the smallest seedlings. It is better to have fewer plants, but stronger plants and bigger grains; in the end, you will have more seeds.

When the plants are 50 centimetres high, weed for a second time.

When you weed, earth up the plants. After you have heaped the soil around the plants, they will make new roots.

HARVESTING

62. When the grains are ripe, do not wait too long before you harvest your sorghum.

If you wait too long, the birds may eat many grains.

After harvesting, you can thresh the spikes and store your sorghum as grain. You can also store the spikes without threshing them.

SORGHUM AS ANIMAL FEED

63. When sorghum is still green, it can be fed to animals. But be careful, because sorghum plants may contain poison.

The quantity of poison in the plants is not always the same; it differs according to the age of the plants, to the variety grown, to the soil and to the climate.

When you cut your sorghum while it is green, new stems sometimes grow on the plants.

These new growths contain a lot of poison.

Be very careful, therefore, when you want to give your animals green sorghum to eat.

Never feed your animals on new growths of sorghum.

When the grain has reached the milk stage, there is less danger of hydrocyanic acid (HCN).

Let the animals feed in the field

They can feed in the field when the spikes begin to ripen.

Feed sorghum hay to animals

Cut the sorghum plants when the spikes begin to show above the stem.

Dry the stems and the leaves.

Because of the poison, wait 2 months before you give this hay to your animals.

Make silage

Cut the sorghum plants when the spikes are well formed, but before the grain is ripe.

Then wait 2 months before you feed this silage.

Never use new growths of sorghum to make silage.

Certain varieties of sorghum are grown only to be fed to animals. These are very good for making silage.

GROWING MILLET

64. The same work is needed for millet crops as for sorghum.

Millet can grow in regions where it does not rain much.

Millet needs a lot of heat and a lot of sunshine.

Millet grows well in sandy soil, and does not like heavy and impermeable soil.

Millet is grown in the regions of the northern savanna.

GROWING MAIZE

WHY MAIZE IS GROWN

65. When maize is ripe, it yields grain.

Maize grain is a good food for people. In some parts of Africa, people eat a lot of maize. Maize is an energy food. Maize can be eaten as flour, or the cobs may be roasted.

Maize grain is a good food for animals. Maize is also a body-building food, it is fairly rich in proteins. It is much used to feed poultry and pigs. Some farmers grow maize to feed their animals.

It is a good thing to give maize to working oxen; the maize grain gives the oxen strength.

When maize is still green, it can be fed to animals.

It can also be used to make silage.

Remember that maize sap needs more soil moisture than sorghum and dislikes drought. On the other hand, the maize plant is not tolerant to waterlogging.

Certain regions could produce more maize to feed the growing population, and also to feed the animals better.

Maize could also be grown for sale to foreign countries.

TRADITIONAL MAIZE GROWING

66. Traditionally, maize is grown in association with other crops.

It is grown in the same field with yams, cotton or groundnuts.

When several crops are grown on the same field, harvests are poor, because sowing is not done at the right time, weeding is not done well, and much time is lost in harvesting.

Traditionally, maize is grown without the use of new tools.

The soil cannot be well worked with the hand hoe, and so the soil is not loose; the roots cannot penetrate well into the soil to take up water and mineral salts; the plants are not well nourished. There is not much grain: the yield is low.

Traditionally, maize is grown without fertilizers.

No mineral salts are added to the soil; the soil becomes poor. Therefore, the old fields must be left fallow and new fields have to be cleared.

This is shifting cultivation.

With shifting cultivation, a lot of land is not cultivated and yields no harvest. Farmers lose a lot of time clearing new fields.

Shifting cultivation must stop in order to increase maize production.

HOW TO INCREASE MAIZE YIELDS

67. Choosing the seeds

If you want a good harvest, you must sow good seeds. You can choose seeds from your own crop.

When you harvest, choose the biggest cobs. Keep these cobs.

For sowing, take only the best-shaped grains from the centre of the cobs.

If you choose your seeds in this way, you will have a better harvest. Seed dressing is also useful.

But yields become smaller if you sow every year seeds from last year’s crop. After a few years, the maize loses its good qualities.

So you must buy new seeds.

68. The research stations have improved varieties of maize, which produce very good seeds.

Several varieties of maize are grown at the research stations.

The female flowers of one variety are fertilized with the pollen from the male flowers of another variety to produce hybrids. Otherwise, selection breeding is carried out within the same variety.

When the female flowers of one maize variety are fertilized by pollen from the male flowers of another maize variety, this is called crossing. The flowers fertilized in this way produce a new variety of maize called a hybrid, which is better than the two original varieties.

But after several years of growing maize from the previous crop’s seeds, this new variety loses its good qualities.

So new seeds have to be bought.

Crossing two varieties may also result in new varieties that are more resistant to disease.

PREPARING THE SOIL

69. Maize needs fine earth, without clods, a loose soil, in order to develop its root system.

Tilling with a plough loosens the soil. The clods are broken up with the harrow.

70. Sowing

Sow your maize at the beginning of the rainy season.

Sow in rows, leaving 80 centimetres between rows. Put 3 to 4 seeds in one hole, leaving 50 centimetres between holes.

Make each hole 7 centimetres deep and cover the seeds with a little earth. Like that the seeds have more protection against rats and birds.

71. How to look after maize

Weeding is very important. This work can be done better and more quickly with an animal-drawn hoe.

Weed for the first time 15 days after sowing.

Pull out the smallest seedlings from holes where all the seeds have come up; leave only the largest seedling.

Weed for the second time when the plants are 50 centimetres high.

When you weed, also earth up the plants.

After earthing up, the plants will have no more adventitious roots, and the maize will be more resistant to drought.

The maize will be better nourished.

MANURE AND CHEMICAL FERTILIZERS

72. Organic manure and chemical fertilizers cannot be used well and it is not profitable to apply them:

• if the soil is not well prepared,

• if the seeds are not well chosen,

• if sowing is not done at the right time, in rows and at a good density,

• if the weeds are not removed whenever they grow,

• if the crop rotation is not good.

73. Different manures and fertilizers have to be applied according to your crop rotation

Different plants do not all take the same amount of each mineral salt out of the soil.

Before sowing maize, you must therefore give back to the soil the mineral salts taken out by the previous crop.

These mineral salts are contained in the fertilizers.

According to region

The soils of different regions do not all contain the same amount of each mineral salt. They must therefore be given different fertilizers.

For example:

If a soil is poor in nitrogen the tips of the young leaves turn yellow. You must therefore add nitrogen to the soil.

Farmers use:

74. Organic manures: these are animal manure and green manure

Organic manures improve the structure of the soil. Plants grow better in a soil of good structure, and the chemical fertilizers are used better.

Organic manuring should therefore be done at the beginning of the rotation, that is, before growing the first crop on a field.

75. Chemical fertilizers

Maize needs above all nitrogen.

The nitrogen fertilizer most often used in Africa is ammonium sulfate.

But maize also needs phosphates and potassium.

Ask the extension services for advice. They will tell you how much fertilizer to apply to your maize field.

For example:

At Bouaké (Ivory Coast), the following fertilizers are applied before sowing 1 hectare of maize:

100 kg   ammonium sulfate,

100 kg   dicalcium phosphate,

50 kg   potassium chloride.

After the first cultivation, another 100 kg ammonium sulfate may be added.

Be careful not to put any fertilizer on the leaves; the fertilizer may burn the leaves.

HARVESTING AND STRONG

76. Harvesting

Maize can be fed to animals when the plants are still green.

In that case cut the maize when the male flowers begin to go dry. You can also make silage.

If you want to roast the maize cobs, harvest the cobs when the grains are not too ripe.

If you want to make flour, harvest the cobs when the grains are quite ripe.

77. Storing maize

Maize cobs can be stored in their husks. That way the cobs keep better.

They can also be stored without their husks, but then the cobs may be attacked by insects. There are insecticides which kill these insects.

SUGGESTED QUESTION PAPER ON FOODS CROPS

If any of the plants mentioned here does not grow in your region, do not answer the relevant questions.

FILL IN THE MISSING WORDS

The stem of the yam thickens in the soil; it is then called a __________

Cassava is propagated by __________

The seeds of sorghum, millet and maize are grouped together in __________

By __________ two varieties of maize, a new variety is obtained.

ANSWER THE FOLLOWING QUESTIONS

What is meant by an energy food?

List the names of the cereals you know.

Why should you sow cereals?

What crop rotation do you use on your fields?

Why must tree stumps be removed from cleared fields?

What can be done against erosion?

How can plants be improved?

Why do we need to grow more food crops?

Why is weeding necessary?

What is the purpose of crop rotation?

What needs to be done before applying fertilizers?

How do you store your yam crop?

How is cassava propagated?

How is cassava planted?

How do you choose grains from your cereal crop to have good seeds?

Why is sorghum grown where you live?

Why is it good to earth up sorghum and millet plants?

Why should cereals be sown in rows?

Do the good qualities of a maize variety last long?

How can a new maize variety be obtained?

How should the maize crop be looked after?

How is maize stored where you live?

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