2IntroductionShifting cultivation is now confined to the humid tropics of South America, Africa and South East Asia.It is estimated that shifting cultivation still supports between 300 – 500 million people.
3Although there are changes taking place in the more accessible areas of the Amazon Basin, traditional shifting cultivation is still found in the more remote, and more thinly populated parts (e.g: Pastaza Province in eastern Equador)
4Shifting Cultivation Vs Bush Fallowing Shifting cultivation is when farmers move their home to farm new land.Bush fallowing (e.g.: West Africa) is where only the clearings are ‘shifted’.The amount of time an area of land is farmed for will depend on the rate of decline in soil fertility and the productivity of the clearings around it.
5PopulationIn North Dakota, USA, where the population is 22, 000 people to 6000 km2.In comparison, the Amazon Basin only has a few hundred people to the same area.
6Low population is low due to a number of factors Shifting cultivation is unable to support a larger population.The road and communication network is very poorThe areas is very isolatedThere is a lack of economic developmentDisease is not a major factor in limiting the population (Although Malaria is endemic and measles, whooping cough, influenza and chicken pox occur).
7The Achuar people are a tribe of the Jivaro Indians.There is a parallel drainage pattern which provide navigable waterways.Settlement is dispersed and may range from1 – 12 houses along the river bank.
11IntroductionThere is plenty of land for cultivation: it is an extensive system in which labour and output are relatively small in relation to the total area of land available.Cultivation is aided by the year-long growing season, characteristic of the equatorial climate.
12Characteristics of a Equatorial Climate Fact File:Precipitation: High, more than 2700mm during a year.403530252015105-5-10-15-20-25280260240220Temperature: Hot! Temperatures are high all year round. The average temperature is 26ºC.200180Temperature in ºC160140Precipitation in mm120100Other Facts: Wild fruits grow between November and March.80604020JFMAMJJASONDMonth
13Step 1 – With the help of stone axes and matches (low technology), the Jivaro Indians clear a small area of about 1 hectare of forest.Sometimes the largest trees are left standing to protect young crops from the suns heat and the heavy rain; so also are those which provide food, such as banana and kola nut.
14Step 2 - After being allowed to dry, the felled trees and undergrowth are burnt (slash & burn cultivation).Advantages – weeds are removed and ash provides fertiliser.Disadvantages – useful organic material and bacteria is destroyed.
15Step 3 – The main crop manioc, is planted along with yams, pumpkins, beans and tobacco. The diet is supplemented by hunting (mainly for monkey), fishing and collecting fruit.ManiocYamsThe productivity of these ‘gardens’ can be very high, estimated as ranging from 2000 to over 20, 000 calories per day.
16Step 4 - Once the forest has been cleared, the nutrient cycle is broken. The heavy afternoon, convectional rainstorms hit the unprotected earth causing erosion and leaching.With the source of humus removed, and the absence of fertiliser and animal manure, the ferralitic soils rapidly lose their fertility.
19Step 5 – Move on. Within 4 or 5 years, the decline in crop yields and the re-infestation of the area by weeds force the tribe to shift to another part of the forest.
20Although shifting cultivation appears to be a wasteful use of land, it has no long-term adverse effect upon the environment. In most places humus can build up sufficiently to allow the land to be re-used within 25 years if necessary.
21Changes in farming in the Amazon Basin Great population pressure and land-hunger in areas beyond the rain forest, (such as North East Brazil), have resulted in immigration by ’colonists’ on a large scale to take up holdings along new roads in the Amazon Basin.Such colonists are from very different environments, and lack the knowledge and faming skills of the native peoples in sustainable land management.
22The Amazon Rainforest has been cleared for the following reasons: Thousands of kilometres of road have been built.People have been given free or very cheap land to farm.Cattle ranching is the most common type of farming requiring large areas of land.Rivers have been dammed to make reservoirs & HEP stations.Minerals have been extracted (eg: tin & iron ore)
23Deforestation - Benefits Has enabled many people to move from areas suffering from drought, famine and overcrowding.Has made it possible to mine valuable minerals that can then be exported.HEP schemes have attracted industries which produce many jobs and save the country importing fossil fuels.Timber can also be exported for profit.
24Deforestation - Problems Fewer plants and less wildlifeFewer IndianTribesProblemsUndrinkablemuddy waterLandslidesLeachedsoilFuelshortages
25SummaryOn a global scale, shifting cultivation is still a very important livelihood.Globally, it is estimated that shifting cultivators clear between 20 and 60 million ha of forest and scrub each year, and then burn between 1 and 2 billion tonnes of dry matter, thus contributing to global air pollution.
26Complete summary sheet Resources:Core Geography pCore Themes in Geography Human p40-43Waugh pYou have 20 minutes!
27Your turnAnswer questions 9a, 9d, 10, 11 on page 256 in Core GeographyResource: Core Geography pagesBB