[page12] Topic 2: Soil, vegetation and Animals

[Ahead]Unit 4 What do plants need to grow?

Plants serve living creatures in many ways. The many crop plants that are cultivated in Zimbabwe provide food such as bread, vegetables and food for cattle. Plants need soil, water and sunlight to grow well. In the following experiments you will be investigating conditions necessary for growth of plants.

[Activityhead]Experiment: Ideal conditions for plants to grow

In this practical experiment you are going to investigate the conditions that plants need to grow.

1.Collect 6 empty, rinsed containers such as yoghurt containers that can serve as pots for germinating seed.

2.Also make sure that you have 6 small flat containers that the plastic one fit onto to collectthe water that drains through!)

3.Make 3 small holes in the bottom of each container for water to drain.

4.Collect 6 to 12 dried uncooked beans or any other seed such as peas, corn or sunflower seeds and bring it to school.

5.Mark your containers carefully as indicated in the table below:

Container number

What to add to germinating seed

Condition

1 Soil from school ground

Poor soil

2 Soil from a garden Good soil3 Garden soil with

enough waterEnough water

4 Garden soil with too little water

Too little water

5 Garden soil in sunshine

Plentiful sunshine

6 Garden soil in shade Too little sunshine

6.Put garden soil in containers 2 to 6 and soil collected from school ground in container 1 as shown in table above.

7.Plant your seeds (at least one per container) about2 cm below surface in each container. Make sure youplant the same number in each container.

8. Add water to each container.9.Place container 5 in full sunshine on a windowsill

or safe place outside. 10. Place container 6 in a very shady spot or

inside a cupboard.11. Container 4 must only be watered every 5th

day.12. Ensure all the other containers are kept

moist.13. Observe your seeds for at least 10 days. If

possible allow more time.

14. Copy the following table in your book and record your observations in the space provided:

15. Your observations can include the height your plants are growing.

Container

number

Day

1 2 3 4 5 6 7 8 9 10123456

[aw: ]

From your observations you should have find that seeds and plants grow better in good garden soil than in the poor soil collected from the school ground. Garden soilcontains more nutrients for germination and growth of plant seeds than soil from the school ground. The seedsthat receive enough water will also grow better than the seeds that were not watered enough. The seeds placed in sunshine also grow faster than in the shade. We can therefore conclude that plants require three things to grow well. Write the three things plants needdown in your book. When you are outside look for plants

that are not growing well and look for the things the plants need. You may look for pests and diseases, time of year, water, soil and temperature.

[Activityhead]Read information from a bar graph

In the bar graph below the amount of water that the main crops plants in Zimbabwe require is illustrated. Study the bar graph and answer the questions that follow:

[aw: [pic27a]Bar graph showing amount of water needed by different cropsKEY maximum amount of water needed minimum amount ofwater needed EXAMPLE: Finger millet rapoko Rainfall:450mm to 600mm Temperature warm to hot – 20°C to 25°C]

1.Which crop requires the most water?2.Which crop requires the least amount of water?3.List the 4 crops that require the same amount of

water. 4.Which crop has the highest range of water

requirements?

[Activityhead]Exercise: read information off maps

Some of Zimbabwe’s major crop plants are illustrated onpage xx to xx. Next to each, is a map showing the areaswhere they grow. Before you look at these, study the

bar graph showing the amount of water needed bydifferent crops.

A map showing the average temperature in Zimbabwefollows. This does not show how hot or how cold a placegets. It indicates the average temperature in one yearin any one area. Use the bar graph and the averagetemperature map to find out the approximate rainfalland the average temperature that the different cropsneed.[aw: maps p28 – 31 [pic28a]Map showing the average temperature in Zimbabwe

[pic28b]Finger milletShona name: ZviyoNdebele name: Uphoko

[pic29a-c]Bulrush millet Shona name: Mhunga Ndebele name: InyawuthiMaize Shona name: Chibage Ndebele name: UmumbuSorghumSorghum prefers a clay soil but will grow in other soils. See soil map on pagexx(33 in old book).[pic30a-c]Sunflower

Ground nuts Shona name: Nzungu Ndebele name: AmazambaneSoya bean Soya beans are high in protein.[pic31a-c]Bambarra roundnuts Shona name: Nyimo Ndebele Name: IndlubuBambarra nuts prefer sandy soils See soil map on page xx (33 in old book).

Sugar cane Shona name: Nzimbe Ndebele name ImfeWinter wheat Shona name: Koroni Ndebele name: Ingqoloyi

Summarise this data in a table with the followingheadings: (Finger millet has been done for you)Name of crop Range of water

neededAveragetemperature

Finger millet 450 – 600 mm Warm to hot 200C –250C

[Ahead]Natural conditions that determine distribution of crop plants

We know already that crop plants require water in the form of rainfall, healthy soil and sufficient sunlight.

Soil

Some plants prefer sandy, well-drained soil, othersprefer heavy clay soil. Sandy soil is less fertile thanclay soil. Most plants grow best in a mixture of sandand clay, called loam soil. The soil fertility can beimproved by adding compost, anthill soil, cattle orchicken manure and artificial fertilizer. It is usuallyapplied before and during planting season. [aw: [pic33b] caption: Different soil regions in Zimbabwe add loam to label: equal clay and sand / loam soil]

Rainfall

All crops require water. Fast growing leafy cropsgenerally require higher rainfall. Sunflower,sugarcane, maize, wheat, and tobacco are examples offast growing thirsty crops. Growing crops need waterfor the duration of their growth.

TemperatureHigh temperatures are required by sugar cane. Somecrops can withstand high temperatures better thanothers, e.g. finger millet and bambarra round nuts.Some crops require cool temperatures, e.g. potatoes andwheat. Sweet potatoes which are different from potatoesgrow in warm conditions.

FrostMany plants cannot tolerate frost (temperatures of 0°Cor below). At the low temperatures, the plant tissue ispermanently damaged and the plants die. Wheat and fruittrees, such as apples, peaches and plums are

exceptions. The benefit of frost is that it kills orreduces pests and diseases during the winter.

[Ahead]Conditions controlled by humans that determine distribution of crop plants

Quality of seeds

It is best to obtain good quality seed. Maize seedshould not be collected from cobs and planted. It maygrow into maize plants but the cobs that these producewill have very few seeds. Maize seed is produced in aprocess whereby the pollen from one variety of maizeplant is used to pollinate the female cobs on anothervariety of maize plant. This produces hybrid maize seedthat produce a large yield of cobs.

Preparation of soil

Soil needs to be prepared before planting. Hoeing orploughing is necessary before planting. Furrows andridges must be made so as to allow rain that falls tosoak easily into soil without washing seed and soilaway. Excess water must be allowed to run off.Ploughing and digging helps to let air into the soil,loosens soil and uproots weeds.

WeedingWeeds must not be allowed to compete with crop plants.They absorb fertilizer and water meant for crop plants.Weeds may also be hosts for diseases and pests.

Diseases

Diseases caused by fungi and bacteria cause leaves towilt. Sometimes diseases are carried by insects, e.g.leaf hopper in maize. Most diseases can be controlledby chemical sprays, called pesticides. Farmers must bevery careful when applying pesticides as it isdangerous to handle and inhale. Farmers must wearprotective clothing, gloves and masks when applyingpesticides.

PestsPests are usually very small animals, mostly insectsthat feed on crops. They do enormous damage. One thirdof all the food produced in the world is thought to beeaten by pests. Pests eat leaves, suck juices out ofstems and growing tips. They may eat flowers and feedinside stems such as maize stalks. Birds can be pests,as are rats which eat seed and young shoots in times ofdrought. Following pest attack, disease may result.Some pests carry bacteria and tiny fungus spores andspread these from plant to plant.The pictures show a few of the common pests that attackcrops. The crops that they attack are indicated.[aw: pic [pic33a] dove sorghum, sunflower semiloopersoyabean, sunflower cutworm, soyabean, sunflower, weaver bird:sorghum, sunflower, army worm maize snout beetle maizequela:sorghum, move caption away from bird’s head! mhunga, wheataphids wheat, sorghum, groundnuts stalk borer,sorghum,maizecaption: Some pests of crop plants]

[AHEAD] DID YOU KNOW?

Zimbabwe has six natural agricultural regionsStudy also the following map which shows the sixnatural agricultural regions into which Zimbabwe isdivided. These are based on rainfall and temperature.Read about the conditions in each region. Find theregion or regions your crop grows in. Read the notesabout the different regions. Use these to add to yourown notes.

[aw pic34a – there are clearer ones on internet, so please replace http://www.fao.org/ag/AGP/AGPC/doc/counprof/zimbabwe/zimbab.htm#CLIMATE AND AGROECOLOGICAL ZONESMap showing natural agricultural regions of Zimbabwe]REGION 1: High rainfall, over 1 000 mm a year.

Temperatures may be higher than 30°C insummer, but is cooler than elsewhere inwinter.Humidity (moisture in the air) high. Cropsgrown: forestry, fruit, tea and coffee.

REGION 2A: Rainfall between 700 mm and 1 000 mm. Summertemperatures range between 25°C and 30°C.Crop production includes maize, cotton,tobacco, soya beans and winter wheat withirrigation.

REGION 2B: Rainfall and temperatures similar to Region2A. Region 2B is different in that severe dryspells may occur during the rainy season. Therainy season may be also shorter than forRegion 2A.

REGION 3: Moderate rainfall 550 mm to 700 mm. Rainfallis less reliable, with dry spells during the

rainy season. Summer temperatures are often30°C. This area is suitable for drought-resistant crops, e.g. sorghum, cotton, fingermillet, barley, tobacco and fodder forlivestock.

REGION 4: Fairly low rain fall; 450 mm to 600 mm withseasonal drought and harsh dry spells duringthe rainy seasons. Summer temperatures areoften 30°C or above. Drought resistant foddercrops for livestock. Crops can be growncrops where irrigation is available.

REGION 5: Rainfall less than 500 mm and not reliableeven for drought resistant fodder crops.Summer temperatures often reach 32,5°C orabove. Crops can be grown if irrigation isavailable, e.g. sugar cane and wheat inwinter. This region is suitable for cattleand game ranching.

[ACTIVITYHEAD] What can farmers do to improve theircrops?

Answer the following questions in your books.

1.How can farmers help to control conditions neededfor good crop plant growth?

2.Which conditions needed for good crop plant growthare controlled by nature?

3.Can farmers do anything about these? 4.Which conditions needed for good crop plant growth

can be controlled by farmers?5.Refer to the previous notes. 6.Make a list of those things that help plants to

grow well.

[AHEAD] DID YOU KNOW?Crop plants are important Cotton/tobaccoCotton and tobacco plants are two crops that isattacked by many pests. The pests are described in thenotes below. Draw a table to compare these two cropplants as below and fill in the missing information.Make a diagram of it. (It does not have to look exactlylike the plant!) Read the labels in the diagrams thattell you about the plants. In your diagram make labelsto show what a farmer can do to help the plant growwell.

Cotton TobaccoDiagram of plant

List of mainpests

What happens toplant afterharvesting?

Ideal conditionsto grow this cropplant.

[aw: pic35] flowers leaves weeds fruit from flowerdevelop into a round 'boll' insect numbers increase

clay soils become hard and cake caption : A cottonplant]

Some insects that attack cotton stay on plants thatgrow next to cotton fields during the winter. A wildhibiscus plant is the host of many of these.

[aw: pic35b Flower beetle: eats flowers Flower beetle

[aw: pic35c-g Aphids: secrete bubbles of sweet juice which ants feed on. Caption: An ant milking an aphidStainer beetle: attacks and feeds inside cotton boil. Fibres become stained. Caption: Cotton stainer beetleWild hibiscus weed: flowers are yellow -grows to 2 m tall and very common weed which harbours pests of cotton.caption: Wild hibiscusTip wilters: such juices from leaves and growing tips of plants. caption: Tip wilter stink bugCotton ball worm: feeds on cotton bollsCaption: Cotton ball worm

One of the main problems in growing cotton is that ofinsect attack. Many different kinds of insects feed ondifferent parts of a cotton plant as it grows.By law, farmers must burn old cotton plants after allthe cotton has been picked. A date is set for this. Whydo you think this is so?One of the main problems in growing tobacco is verysmall worm-like creatures that attack the roots oftobacco. They live inside the roots and form bumps andnodules on the roots. These pests are called nematodes.

To avoid nematodes farmers use seeds that produce plantsresistant to nematodes. The soil is also treated with achemical before seeds are sown. This chemical is verypoisonous.Tobacco likes high temperature and high rainfall. Itgrows on sandy or clay soils. Tobacco seeds are very small. They get blown awayeasily and lost. It is best to grow seeds in seed bedsfirst and later plant out seedlings in holes dug in thefields.Sometimes seedlings are planted out before the rainsstart. What will help these seedlings survive? Aftertobacco leaves are picked they must be hung up in barnsand carefully dried and then graded. Tobacco also hasto be destroyed by a certain date after reaping.

[aw old book: pic36aFlowers are pinky at top of plantholes in leaves from hailhail causes damage to leaves and much loss to farmersweeds compete with tobacco plantsnodule on rootsvirus diseases make leaves look pitted and blotchyaphids and various insects eat leavesnicotine inside leaves is poisonous to some insectsnodule of root with nematodes insidepart of rootcaption: A tobacco plant. Nematode root nodule

[Activityhead] Write about a crop plant

1.Choose one crop that you have learnt about. 2.Make a diagram of the crop plant and its seed.

3. Include a small map showing where it is found in Zimbabwe.

4.Describe the ideal conditions for growing this cropplant.

5.Study the map of the soil types of Zimbabwe and decide if your crop plant is growing in an ideal soil type.

6.Explain how you will look after your crop plant to make sure you have a big harvest at the end of the growing season.

7.Do not simply copy the notes from the book, but write it in your own words.

8.You may decide to do another crop plant found in Zimbabwe, for example one that grows where you live, for example tea, coffee, tobacco or cotton.

Revision

L Plants require good soil, enough sunlight and sufficient water to grow.

L A range of crop plants such as maize, cotton, tobacco, sugar cane, wheat and ground nuts are cultivated in Zimbabwe.

L These crops plants each have a specific temperaturerange and soil type preference.

L There are six natural agricultural regions in Zimbabwe that each have its own conditions for crop plants.

L There are a number of natural factors such as rainfall, temperature, frost, and soil that determine success of a crop plant.

L Human activities also determine the success of the agriculture. These activities include seed quality, soil preparation, weeding, pest and diseases control measures.

Revision

Choose the correct answer to each question.1. For maize plants to grow well they should be:

A checked often for snout beetle. B planted early in the hot dry season. C planted in soil without lime. D planted in mostly clay soil.

2 Which of the following crops require the largest amount of water?A wheatB maize C sorghumD groundnut

3 Which of these crops is an excellent source of proteins?A sun flower seedsB soya beanC maizeD rapoko

4 When choosing maize seed, the most important thing to consider is whether the seed:

A germinates quickly. B is drought resistant.C is high yielding.D is suitable for the climate of the area.

5 Ploughing and digging soil:A allows good earthworm activity. B gets rid of most of the soil pests.C helps loosen it and let air in. D kills weeds and stops them growing.

6 Some conditions cannot be controlled by farmers, oneis:A pest damage. B seed quality. C soil erosion. D temperature range.

7 Which of the following crops are resistant to frost damage?A winter wheatB sunflowerC bulrush millet D sugar cane

[Ahead]New words

Germination: The first stages of growth of a seed when it is in good soil and receive water.

Pests: A living creature that has a harmful effect on plants, animals or humans. It often cause diseases.

Loam soil: Good soil to plant crops in that contain a mixture of sand, clay and humus.

Compost: Naturally decomposing plant material such as fallen leaves and peels of vegetables that is added to soil to improve nutrients.

Artificial fertilizer: Man-made chemicals that is added to soil to improve it for planting of crops.

Frost: When it is very cold on winter nights, the air temperature drops below freezing. It cause damage to plant as the cells die and plant cannot grow.

Hybrid maize seed: Hybrid seeds is the result of a cross between 2 different species of maize. It ensures that the cobs are large and the yield very high.

Hoeing : To use a hoe to dig up the soil. It improves the air content in the soil.

Fungi: A group of living creatures that include mushrooms, yeasts and rusts. Some cause diseases on crop plants and are pests.

Bacteria: Very small single-celled living creatures that are found everywhere. Some cause diseases on crop plants and are therefore pests.

Pesticides: Chemicals that are applied to crops to killpests such as fungi or bacteria. Pesticides must be handled carefully as they can cause diseases in humans.

Humidity: The amount of moisture in the air. When the air is dry, the humidity is low.

Drought-resistant: Crop plants that do not need a lot of water to grow well. It is easier to grow plants thatare drought-resistant.

Nematodes: Very small worms that cause damage to crop plants like tobacco.

[page 20]

[Ahead]Unit 5 Different animals live in different habitats

[Ahead]Animals are found in habitats

Zimbabwe has a rich wealth of wildlife. In this sectionwe are going to investigate the habitat of a number of well-known animals. The habitat of an animal is the area where it is found in naturally. There are a large number of habitats available and animals are adapted tofind food, shelter and raise their young in their habitat.

[Activityhead]Project 1: Construct a diorama

A diorama is a three-dimensional miniature scene in which animals are shown in their natural environment. Your diorama must contain animals found in Zimbabwe.

1.Decide on a base for your diorama. A shoebox works very well, but any reusable container - cardboard, plastic, or tin – can work.

2.Create the background. You may use coloured paper or colour it in.

3.You may use paper to construct your animals. Remember to cut out a base for your animals to stick it down.

[aw: pic like this to give an idea of what it should look like.

4.Cut out and colour in your animals.5.Glue your animals into place. 6.Bring your diorama to school and share with your

friends.7.Describe the habitat of your animals to your

friends and let them compare theirs to yours. 8.Discuss how your dioramas are the same and

different. 9.Explain the feeding relationships between your

animals to your friends.

[activityhead]Answer the questions

Animals live in natural habitats in the environment. Not all places are alike. Answer these questions.

1.How is a garden different from natural veld vegetation?

2.What is the difference as a habitat between a tree and a stack of large stones?

3.How is a gum tree woodlot different from a grazing land?

4.How is a yard in a township different from the roadoutside?

[activityhead]Exercise: Territories within a habitat

In this exercise you have to study a map of a Gamepark. A number of features are present in theenvironment which represents the habitats of a numberof animals. It is a protected place with a game fencearound the outside. No cattle or goats enter the area.

Study the map and look at the key. Notice that manydifferent animals share the same large habitat.However, each kind of animal has a territory within thehabitat. A territory is the area in which the animalhunts, feeds, hides, sleeps and breeds. Differentterritories are shown. Some animals need largerterritories than other animals.

Study the map and answer these questions.1 The territory of the impala overlaps with which

other territories?2 Why does the lion have large territories?

3 Which animals have a source of water within their territory?

4 Which animals would have to leave their territory when they need water?

5 A dove is a common bird, dependent on trees for cover and safety. For what will it leave its territory?

6 Which animals can be hunted by lion within the lion's own territory?

7 Which animal uses the rocks for cover (hiding)?8 Which animal compete with the leopard?9 Why are animals afraid and alert when they go to

drink water at a waterhole?

[aw:pic39aTerritories within a habitat in a Game park;

[Activityhead] Exercise: A rat territory

[aw: [pic40a Rats territory]

The map above shows the territory used by a group ofrats. The map does not show the huts where people liveand sleep. It does not show the thatched roof over thecooking area.

Study the map above and answer the following questions.

1 Rats are nocturnal. This means they are active at night and sleep during the day. What advantages doesthis have for them? Why are they not active during the day?

2 Where would rats most likely sleep and hide during the day?

3 Do rats need water?4 What do rats feed on?5 Where would it be safe for rats to make nests and

rear their young ones?6 Rats are born every six weeks to the same mother.

They are born without fur and with eyes closed. Theyare small (2 cm long), pink and defenseless. What will new born rats need?

7 Do rats climb trees and poles?

Zimbabwe experienced a severe drought in 1991/1992.The rat population increased to plague of rats. Onetheory is that the drought killed off many of thepredators of rats such as snakes and owls. Predatorsbreed slower while rats multiply quickly. Rats arefound almost everywhere food is available; on farms, insuburbs, stores, in veld and on kopjes. They are smalland hide easily. They eat many different kinds of food,e.g. grass seed, humans’ wastes as well as each other.One could say that the habitat that rats require ispresent almost everywhere where there is warmth, waterand a food source.

[activityhead] Project 2

Constructing maps and models of animal territories

Study an animal that you see often. It can be abird, spider or lizard. Other suggestions to choosefrom are: cats, frogs, dog, crows, insects, orrats.

Make careful observations of exactly where it goesfor a few days.

Make a map showing the territory used by an animalyou are familiar with in your own environment.

Does it always seem to be in one place at acertain time? Some territories may be very small,e.g. a spider territory may be confined to a wallor outside place. Some lizards on trees and stoneshave very defined and limited territories. Have youseen birds fighting off other birds for wanting tocome to their tree or place?

Try to make a model of your animal territory, usingclay, plasticine, cardboard and glue. Show wherethe animal goes by marking its favourite routes andhiding places.

Indicate where it gets food and water from. Make a list of things that your animal needs to

obtain from its territory.

[Ahead] Habitats of wild animals

A national park provides many different habitats suchas kopjes, bush areas, rivers and grassland for wildanimals. The habitat in which wild animals live mustmany needs such as:

space for hunting or feeding. water.protection and places to hide in. natural vegetation for camouflage and food.other animals for predators to feed on. other animals of the same kind to mate with.the absence of people who change naturalenvironments.

[activityhead]With these in mind discuss in your groups how each ofthe following may have affected the habitats wildanimals require:

drought and change in weather patterns.increase in human population.

Without suitable habitats wild animals cannot survive.Think too of the effects of poaching on wild animalnumbers.

[aw: write brief or refer to aw in old book to reuse…]

1.Explain why water sinks more quickly into sandy soil.

2.Explain why water sinks more slowly into clay soil.

Remember

L Air spaces between sandy soil particles are large.

L Air spaces between clay particles are small.

L Water sinks quickly into sandy soil.

L Water sinks slowly into clay soil.

L Water sinks into some stones but not into others.

[Activityhead]Revision

Answer the questions and then check your answers on page XX.

1.Which of these statements is true?A Water sinks into soil.B Water goes on sinking forever.C Water sinks easily into stones.

2. etc.

[Ahead]New words

Predator: An animal that hunts, kill and eats another. It is usually a large carnivore with good hunting skills, for example a lion.

Habitat: The natural environment in which an organism lives.