Review of Efforts to Combat Desertification and Arrest and Reverse Land Degradation in Myanmar - Combating Desertification in Asia, Africa and the Middle East - page 272

• Light-textured Luvisols;

• Scanty rainfall and arid soils throughout the year;

• Unprotected crop fields, lack of natural forest barriers;

• Soil-loosening crops such as major oilseed crops predominate;

• Hot and dry winds suck away meager moisture stored in the topsoils.

In the Kyaukpadaung area, the erosion problem is severe with 50 % of the
cultivated land losing its top horizon; this means that most of the fertile soil has been
lost through severe sheet and rill erosion. Infiltration and the water holding capacity
of these soils are limited. Erosion rates on cultivated land range from 50 t/ha/year
for optimum soils on gentle slopes to 150 t/ha/year on slopes of 3-15 % with sandy-
loamy or sandy-clay-loamy soil. Many hillsides are almost bare, rocky, compacted
and heavily crusted. In the Magway area, there is a high level of erodibility, because
of the sandy topsoil. Soil loss was estimated at 30 t/ha/year on better lands with
gentle slopes ( 3 %) and over 75-100 t/ha/year on undulating lands with sandy

loams, surface crusts and low water holding capacity. In the Chaungoo area, the
erosion problem follows the same pattern as Kyaukpadaung, mainly in the upper
parts of township areas, showing similar severity and rates of erosion and runoff.
Depletion of soil fertility is a serious problem in Myanmar as the most eco-
nomically important soils of the country are found in these problem areas. It was
estimated that about 12.3 % of the total land area situated in the central dry zone
faced depletion of soil fertility as well as soil nutrient imbalance. All the agricultural
lands on Luvisols in central dry zone areas have depleted soil fertility generated by
the following factors:

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• Very light in texture (sandy loam to loamy sand);

• Too low in moisture and very high in temperature;

• Rolling and undulating and prone to wind and water erosion;

• Completely deprived of organic matter;

• Yearly cropping without any fertility improvement measures such as green

manuring, composting and balanced fertilizer application.

Soil fertility depletion is also found in the Shan Plateau due to water erosion, high
acidity and lack of soil improvement techniques. Since this degradation problem is
a serious one, it needs to be addressed urgently.
Approximately 1.4 % of the whole country is affected by both salinization and
alkalinization that cause land degradation. Coastal strips, deltaic and arid regions
are impacted by salinization while alkalinization is confined only to certain areas
of the arid region. Types of soils under the salinization category are Gleysols and
Vertisols, while Vertisols mainly occur in the alkalinization category. Salinization
occurs in the coastal and delta regions due to seawater intrusion. Although heavy
rainfall (over 4,000 mm) and flooded rice cultivation annually flush out deposited
salts, high tides and high evapo-transpiration in the summer make the soils more
saline. Thus, the salinity effect is more harmful to dry season crops. Salinization
in the central dry zone is mainly caused by saline groundwater evapo-transpiration
which results in salt crusts on the soil surface.