Review of Efforts to Combat Desertification and Arrest and Reverse Land Degradation in Myanmar - Combating Desertification in Asia, Africa and the Middle East - page 271

zone are mainly commercial, cultivating a variety of crops in a double cropping
and rotational system. Intercropping is widely practiced in Chaung U, Sagaing
and Kyaukpandaung, Mandalay while less in Magway. Poorer farmer families and
laborers fulfill their incomes by cutting fuelwood or making jaggery both of which
contributed to overexploitation of forest resources that tends to lead to deforestation.

4 Land Degradation/Desertification

The soils have eroded to varying degree and at some places they have been
completely removed by water and wind erosion. The soil erosion is intensive
and rapid as a result of heavy showers and a low degree of compaction of
rocks. The surface runoff has been estimated to be 30 %. Removal of the natural
savanna vegetation quickly leads to erosion, which is more intensive at the start
of the monsoon rains on bare soils. Rates of soil erosion depend on the type and
effectiveness of cover on the soil surface (Table 14.1 ). Some arid and semi-arid lands
can support crops, but additional pressure from greater populations or decreased
rainfall can lead to the loss of the present plants. Under these circumstances, the
soil becomes exposed to wind, causing soil particles to be deposited elsewhere. A
result of this is the erosion of the top layer of soil. The rate of evaporation increases
due to the absence of shade and salts become drawn up to the surface. This leads to
salinization and inhibits plant growth.
Wind erosion is a problem of arid and semi-arid regions with a dry season of
more than 6 months. In such areas, natural vegetation is steppe-like with much bare
soil. The fine particles of the soil such as clay, silt and organic matter are blown
away by strong winds while coarse materials are left behind. The wind erosion starts
at a wind speed of 25 km/h. Sand grains of 0.5-2 mm are rolled, fine sands of
0.1-0.5 mm are transported over few meters and finer particles such as clay, silt and
organic matter go into suspension in the air. In Magway, dust cloud or 'Red sky'
during March and April is due to this suspension.
About 11 % of the total land area is affected by wind erosion, which occurs
mainly in central dry zone areas that are economically important to the national
economy. Wind erosion effects are well recognized in the central dry zone areas for
the following reasons:

Table 14.1 Areas of
problem soils in Myanmar

No. Soil type Area (000 ha)

1. Saline soil 607.54

2. Alkaline soil 52.63

3. Localized problem soils (acid

sulfate soil, degraded structure,
peaty soils, swampy soils)

300.04

Total 959.52