Chapter 01 : The environment

Introduction

When you were in Standard Four, you learnt about rural and urban environment, and about activities that cause environmental degradation. You also learnt about environmental conservation. In this chapter, you will learn about human activities that can cause environmental degradation. Such activities include agriculture, mining, fishing and manufacturing. Likewise, you will learn about the causes and effects of the destruction of sources of water. You will also learn how to conserve sources of water.

The meaning of environment

The word environment means all things that surround human beings. These include living and non-living things. The environment is composed of natural and man-made features. Therefore, we can say that the environment is a combination of many things, including climate, animals, plants, soil, mountains, valleys, oceans and infrastructure.

Environmental degradation

Environmental degradation refers to the destruction of the natural environment. The natural environment consists of land, water, air, plants and animals. Human activities can be carried out efficiently in a well-kept environment. However, if not done properly, human activities can cause environmental degradation. Improper use of the environment makes the environment lose its value, thus affecting the production of crops and livestock. The effects of environmental degradation include loss of soil fertility, which, in turn, causes a decline in the production of crops and livestock. However, manufacturing industries produce smoke and dust which cause air pollution. Air pollution may cause respiratory diseases like cough and flu. Also, improper disposal of industrial waste causes water pollution.

Human activities contributing to environmental degradation

Human activities can contribute to environmental degradation, if they are not done properly. Human activities include crop cultivation, livestock keeping, fishing, manufacturing and mining. It is very important to understand how these human activities affect the environment, if they are not managed properly. Some of these human activities are discussed below.

Crop cultivation

Crop cultivation is an activity that involves growing various crops. These include food and cash crops. Examples of food crops are: maize, rice, cassava, millet, sorghum, banana and groundnuts. Examples of cash crops include cotton, coffee, sisal, cashew nuts and tea. These crops are cultivated in different parts of our country, depending on the climate of a given area. Table 1 shows the major food and cash crops produced in various regions in Tanzania.

Table 1: Major food and cash crops produced in various regions in Tanzania

The benefits of crop cultivation

Crop cultivation provides us with food and raw materials for industries. It also gives us foreign and domestic currency when we sell crops. In general, it gives our country an identity through the production of the raw materials and crops which we export. For example, our country is very famous for quality cashew nuts, which are cultivated in Mtwara and cotton, which is cultivated in Mwanza. Crop cultivation also provides employment to many people in Tanzania.

The effects of poor crop cultivation practices on the environment

Crop farming activities can cause environmental degradation if they are not done properly. For instance, cultivating crops on steep slopes without using terraces results in soil erosion. Also, shifting crop cultivation that involves clearing trees or forests leads to soil erosion and drought. In addition, improper use of chemical fertilizers and pesticides reduces natural soil fertility and kills living organisms in the soil. These organisms are useful in breaking down organic materials for releasing nutrients into the soil.

Improper crop farming practices lead to the loss of natural vegetation, leaving the soil bare, and hence easily affected by soil erosion. Another effect is the drying of water sources. These practices can affect living organisms, including human beings, animals and insects as they may die of hunger and diseases. Figure 1 shows some of the effects of improper methods of crop farming.

Figure 1: Affected land due to improper cultivation practices

Addressing the effects of poor crop cultivation practices on the environment

There are various ways that can be used to overcome the effects of environmental degradation caused by poor cultivation methods. One is the use of terraces on steep slopes to control soil erosion by run-off. Another is the growing of more than one crop in the same area or on the same farm. This type of farming helps to increase soil fertility. Third, crop rotation can also be used. For instance, a farmer can plant maize on a farm this year and the following year he or she can plant beans or other leguminous plants, which increase soil fertility. Fourth, more organic fertilizers should be used than chemical fertilizers and pesticides. Organic fertilizers include humus or animal manure.

Lastly, trees should be planted in bare land and in places where shifting cultivation is practised in order to prevent soil erosion. It is also important to plant trees on the slopes of mountains in order to control soil erosion.

Livestock keeping

Livestock keeping is an activity which deals with animal rearing. The animals kept include cattle, goats, sheep, chickens and ducks. There are three types of livestock keeping: zero grazing, free-range rearing and nomadic pastoralism.

In zero grazing, animals are kept and fed in a confined place. This type of grazing allows one to keep only a few animals. Sometimes, cattle, goats and sheep are kept on large farms owned by the state, companies or some individuals. These farms are called ranches. Examples of such ranches in Tanzania are in Kongwa District and West Kilimanjaro.

Another type of livestock keeping is free-range rearing. In this kind of animal rearing, pastoralists take their livestock into grazing areas in the morning and take them back home in the evening.

The third type of livestock keeping is nomadic pastoralism. In this kind of livestock keeping, pastoralists move with their livestock from place to place, looking for pasture and water. Figure 2 shows pastoralists grazing livestock. Sometimes, pastoralists walk a long distance before they reach a place where pasture and water are available. In Tanzania, livestock keeping is common in Mwanza, Mara, Shinyanga, Tabora, Singida, Dodoma, Kilimanjaro and Arusha. Some of the ethnic groups which practise nomadic pastoralism are the Masai, Barbaig, Sukuma, Nyamwezi, Meru and Gogo.

Figure 2: Pastoralists grazing livestock

The benefits of livestock keeping

There are many benefits of livestock keeping. One of them is the provision of meat, milk, skin, hoofs and manure. Animal skins are used to make various items such as shoes, bags, belts and drums. Hoofs are used to make glue. Also, animals provide us with manure which is used in crop cultivation activities. The products of livestock keeping can be used as a source of food and income. Moreover, we get domestic and foreign currency by selling livestock and dairy products.

The effects of poor livestock keeping on the environment

Overgrazing is the practice of keeping a large number of animals in a small area. This often leaves land bare because the animals feed on all grass and other kinds of vegetation cover. Also, when the animals walk over the land for a long time they cause the soil to be compact and hard for vegetation to grow. The land gets exposed to agents of erosion, that is, wind and water, which remove the top layer of the soil. This process is called soil erosion.

When the eroded soil is deposited in dams and other water reservoirs it causes silting. Silting decreases the volume of water and may lead to the drying of dams and other water reservoirs. This eventually causes shortages of water for domestic use and for livestock and other organisms.

Nomadic pastoralism causes deforestation in areas where pastoralists establish temporary settlements and kraals for their animals. Pastoralists also cut down trees for firewood. As they move from one place to another, they continue to cause environmental degradation.

Strategies for controlling the effects of poor livestock keeping on the environment

There are various ways to control the effects of poor livestock keeping on the environment. One of the strategies is to avoid keeping a large size of livestock in a small area. Reducing the size of livestock will ensure that the grazing area is enough for the number of animals kept. This will significantly reduce soil erosion. For this to be successful it is important to educate livestock keepers on the advantages of keeping few quality animals, which will produce better products such as milk, meat and skin.

Another strategy is zero grazing; livestock are kept at home and in small numbers. Also, ranching can be used to keep animals in a specified area and fed on hay.

Manufacturing

Manufacturing refers to the processing of raw materials using machines to produce useful products or goods. These products may be clothes, mattresses, cars, iron sheets, motorcycles, food products and drinks. There are two kinds of manufacturing industries, these are; those which produce raw materials and those which produce consumable goods. Examples of raw material processing industries are cotton processing industries that produce cotton fibre and sisal processing industries that produce sisal fibre. Other industries use the products of processing industries to manufacture consumable goods. For instance, a textile industry uses cotton fibre to make clothes and industries which use sisal fibre to make carpets.

The benefits of manufacturing

Manufacturing helps to add value to raw materials in order to get products for different uses. Manufacturing industries help to increase the national income, since the products are sold inside and outside the country. Also, when the products are exported to other countries, we get foreign currency. Furthermore, manufacturing industries provide employment to many people. Those who are employed in manufacturing industries need goods and services that can be provided in neighbourhoods and therefore, provide a market for goods from other activities.

The effects of manufacturing activities on the environment

Manufacturing industries may cause various environmental problems, including air, water and land pollution. The problems occur because manufacturing industries produce waste such as toxic gases, smoke, dust, solids, sewage and noise. These pollutants are harmful to the environment because they affect living organisms, including human beings. The air pollution caused by industrial activities causes various problems such as skin and respiratory diseases. It also contributes to climate change. The gases emitted from manufacturing industries may cause acid rain and deplete the ozone layer. Improper disposal of industrial waste can lead to water and soil pollution. Soil and water pollution affects organisms that live in water and on land. Solid waste like plastic bags and bottles, if not disposed properly, can also pollute the environment.

Controlling the pollution caused by manufacturing industries

The environmental degradation caused by manufacturing activities can be controlled by locating industries far away from human settlements. Also, the emissions and waste from industries can be treated before they are released into the environment. For example, industries should construct smokecleaning chambers to clean up toxic substances and dust before releasing them into the atmosphere.

Industries should plan for recycling waste that can be used for other purposes. For example, paper that has been used can be returned to the industries and be processed to get paper again. Waste paper can be used to make charcoal. Other kinds of garbage can be transformed into fertilizer. Also, soundproof systems should be installed in industries to reduce noise

Mining

Mining is a process of extracting minerals from the earth. Minerals are a collection of solid chemical substances which are found in the earth's crust. Examples of minerals are gold, diamond, iron, coal, copper and salt. Salt is obtained through the evaporation of ocean water, which leaves behind salt crystals. Also, salt can be obtained through the evaporation of underground salty water. Mining can be done using simple machines or hands with the help of simple tools such as hoes and pick axes. Small-scale miners use simple tools. Larger-scale mining uses huge plants and machinery. Table 2 lists some minerals and the areas where they are found.

Table 2: Types of minerals found in Tanzania

The benefits of minerals

Mining is beneficial to individuals and the nation. Mining helps people to get jobs and raw materials for different industries. Moreover, minerals like gold, silver and diamond can be used as ornaments. Salt is used for domestic purposes and for preserving food such as fish and meat. Diamond is used to cut hard substances as well as glass, and for drilling rocks. Some of the minerals are exported to other countries to earn foreign currency. Minerals promote our country to international communities. For example, Tanzanite is found only in Tanzania, so it makes Tanzania known to various countries.

The negative effects of mining on the environment

Mining can cause environmental degradation, if not properly done. Mining can cause soil erosion and leave large ditches on the ground. As a result, other productive activities like agriculture cannot be done in areas with large ditches. The dust and smoke from mining sites pollute the air. This can cause human diseases. The diseases include those of the respiratory system, eye and ear infections, and other diseases affecting people who are allergic to dust. The chemicals used in mining such as mercury pollute the land and water sources. When mercury gets into the soil and water sources, it affects aquatic organisms, plants and human beings. Mining areas are often affected by floods because of lack of vegetation. For example, Mererani and Geita are sometimes affected by floods because natural vegetation has been cleared where mining activities are done. This causes water to flow on the surface, instead of percolating into the soil. The eroded soil can enter rivers, lakes and dams, thus causing siltation and flooding. In addition, the removal of natural vegetation can cause drought.

Ways of reducing the negative effects of mining on the environment

The effects of mining on the environment can be reduced by using proper mining methods and filling up the large ditches left behind after mining. Another way is to plant trees and grass in the affected areas to restore vegetation. Also, treatment of gaseous and liquid waste before releasing them to the environment is another way of reducing the negative effects of mining on the environment. It is also recommended that an environmental impact assessment should be done before mining begins in a particular area. Miners should adhere to the laws and regulations relating to land use and mining in order to reduce the negative effects of mining on the environment.

Exercise 2

Answer the following questions:

1 . Mention two types of manufacturing industries.

2. Explain the benefits of manufacturing industries.

3. List four effects of manufacturing activities on the environment.

4. What are the effects of the smoke from manufacturing industries on human beings?

5. What is a mineral?

6. Mention three benefits of mining.

7. Explain three effects of mining activities on the environment.

8. Why are mining areas likely to be affected by flooding?

9. What should be done to areas degraded by mining activities?

Fishing

Fishing is an activity which involves harvesting or catching fish or other aquatic organisms for food or trade. Fishing is done in lakes, rivers, dams and oceans. Examples of sea water fish are the octopus, kingfish, silverfish and shark. These are salt water fish. Fresh water fish are found in lakes, rivers and dams. Examples of fresh water fish are gray tilapia, mud fish and the Nile perch.

The benefits of fishing

Fishing provides us with many benefits, including the provision of employment to communities that live near fishing sites. Also, fishing provides raw materials for industries that process fish products. Fishing contributes to individual and national income. In addition, fishing provides foreign currency through the export of fish and fish products. Moreover, fishing provides us with food.

The effects of improper fishing methods on the environment

There are different methods of fishing. These include fish nets, fish hooks and others. Proper fishing methods include the use of proper nets that catch mature fish. Improper fishing methods are sometimes known as illegal fishing methods. They include those that catch immature fish and destroy fish breeding grounds. Examples of poor fishing methods include the use of poison or explosives to catch fish. The use of poison pollutes lakes, rivers and oceans. Polluted water causes the death of aquatic organisms, decreases biodiversity and disturbs the aquatic ecosystem. Moreover, fish which are caught using poison are harmful to human beings.

Likewise, the use of drift nets is not recommended because these nets may catch immature fish and eggs which, if allowed to grow would be more useful to our communities and the country.

Strategies for controlling improper fishing

The effects of improper fishing can be controlled by educating fishermen on the effects of using explosives, poison and drift nets. Also, the laws restricting improper fishing should be enforced seriously in order to improve fishing activities. Fishermen should be provided with loans so that they can purchase equipment and should be educated on how to use proper fishing equipment.

Water sources

Water is a very important resource to living organisms. There are three main sources of water.

(a) Underground water

(b) Surface water

(c) Rain water

When it rains, some of the water flows on the surface of the earth and some of the water infiltrates into the ground and is stored in rocks. Ground water can come to the surface through springs, wells or rivers. Water is used for domestic purposes such as cooking, drinking, bathing and washing clothes. Water is also used in industries for cooling machines and processing raw materials. Likewise, water is used for irrigation and for the generation of hydroelectric power. In the process of generating electricity, water is used to turn a turbine whose force generates electricity. Examples of hydroelectric power stations in Tanzania include Nyumba ya Mungu in Kilimanjaro, Mtera in Iringa and Kidatu in Morogoro.

Activities that can degrade sources of water

Many of the activities which are carried out by human beings require extensive use of water. Various economic activities can destroy sources of water. Actions that could destroy sources of water include the cultivation of crops close to water sources, feeding livestock in water sources, cutting down trees and burning forests. Similarly, the disposal of domestic and industrial waste into or near water sources contaminates water. In addition, the establishment of settlements close to sources of water can cause these sources to dry up.

Effects of the degradation of sources of water

The destruction of sources of water has various negative effects on living organisms. One of the effects is shortage of water for domestic and industrial use. The destruction of sources of water also affects agricultural and fishing activities. The pollution of water sources causes diseases such as typhoid, cholera, diarrhoea and dysentery.

Conservation of sources of water

Taking into consideration the importance of water, we need to conserve sources of water by planting water-saving trees such as figs around them. It is also advisable to stop cultivating crops or building houses near sources of water. Domestic and industrial waste should not be directed into sources of water. We should also avoid cutting down indigenous trees around sources of water. In addition, the laws that restrict the carrying out of economic activities around sources of water should be enforced. Most importantly, communities should be educated on the importance of water and sources of water and on how to conserve them.

Exercise

Answer the following questions:

1 . Mention human activities that destroy sources of water.

2. Mention four effects of the degradation of sources of water on living organisms.

3. Describe three ways used to conserve sources of water.

Vocabulary