Why might this be a good business opportunity? Why might it not be a good idea?
aridity infertility irrigation salinization leach (v)
- Lack of freshwater
- High temperatures and strong sunlight
- Low rates of precipitation (>250mm per year)
- Short rainy season
- Negative water balance = evaporation > precipitation = high levels of salt in soil
- Salt in soil draws water out of plants making them wilt
- Infertile soils b/c low organic content
- Infertile because very thin soils
- Lack of clay minerals
- Salts are not leached from soil
- High temperatures and long sunlight hours = long growing season
- Good potential for farming where water is available
- Oases, desalinisation of water and exotic rivers provide opportunities for settled agriculture
- Dams collect water which can be used for irrigation
- Read pp 127 -128
- Outline the main opportunities and challenges for farming in hot, arid areas
- What is negative water balance and how does this affect farming?
- Explain the difference between arid desert soils and infertile desert soils.
Ways to make farming in arid areas sustainable
Create a poster for a rural area in Senegal that explains how to farm more sustainably. Your poster should explain these points using visuals to ensure a high rate of access in areas with low levels of literacy.
- Reduce herd size to limit pressure on vegetation
- Use solar panels to produce energy, not animal dung
- Use animal dung to fertilise soils
- Plant vegetation to feed animals
- Use effective irrigation (drip and sprinkler irrigation) instead of flood irrigation
- Put an impermeable layer in irrigation channels to reduce seepage
- Build check dams and diguettes to collect water
- Use more salt-tolerant plants
- Watch the video individually with headphones
- Pause to note key information, facts and data
- Read and make notes on the BBC article
- Make a copy of the flow chart below on A4 paper
- Add colour and illustrations
causes and development of desertification
CASE STUDY: desertification IN SENEGAL
acacia project, senegal
case study: DESERTIFICATION IN niger
TASSA METHOD IN NIGER
SUSTAINABLE FARMING IN THE SAHEL
"Agriculture in hot, arid areas inevitably results in desertification". Discuss this statement. (10 marks)
Candidates are expected to consider points on both sides of this question. The strongest responses may choose to challenge the statement, and may well conclude that while agriculture in such areas may result in desertification, such an impact is by no means inevitable but depends, in part, on the nature of the agriculture involved. Careful choice of crops, cultivation techniques and continuous monitoring may enable successful small-scale or commercial agriculture in hot arid areas. It is likely to be easier to avoid desertification in areas where irrigation is possible than in areas where, for financial, technological, or other reasons, irrigation is not possible.
Desertification is often the result of unsustainable farming, in which more minerals and nutrients are taken out of the soil than are replenished, or where the density of grazing animals exceeds the normal carrying capacity. Some experts also attribute desertification in some areas to on-going climatic change.
Answers that consider only one side of the question should not be credited above band D. It is expected that answers reaching bands E and F will offer supporting evidence and/or exemplification before arriving at a clear conclusion to the question.