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Soil is formed by weathering of parent rocks and decomposition animal and plant matter. Factors such as climate, parent rock, vegetation cover and slope land areas are important in the formation of soil. The quantity of rainfall and the period of receiving rainfall are the most important factors that help in the development process of soil in Sri Lanka. Constant rainfall and high temperature expedite the weathering process of rocks. Although Sri Lanka is a small island, a number of soil types are found due to the influence of various factors. In this chapter we discuss seven main soil groups in Sri Lanka.
•Red brown soil
•Non calcareous brown soil
•Reddish brown latosol soil
•Red yellow podzolic soil
•Red yellow latosol soil
•Alluvial soil
•Solidex and Solonetz soil

How to use the soil

Red brown soil

It is found only in the Dry Zone and is suitable for cultivation of dry crops and chena cultivation.

Non calcareous brown soil

It is found in the interior areas of Ampara, Batticaloa and in the coastal areas. This is more suitable for the cultivation of grains, vegetables and grasses.

Reddish brown laterite soil

It is commonly found in the Wet Zone. This is more suitable for the cultivation of of tea, rubber, coffee, cocoa, cardamoms, cloves and fruits.

Red yellow podzolic soil

This soil is found in the districts that belong to the low country wet zone. Tea, rubber, coconut are some permanent crops which can be grown in this area. This is also suitable for growing vegetables and fruits.

Red yellow latosol soil

This can be seen in the land area from Puttalam to Mullaitivu along the North Western coast of the Dry Zone, and in the Jaffna peninsula. This could be made suitable for fruit cultivation successfully with the use of fertilizer and proper water supply.

Alluvial soil

It is spread in river valleys and areas around them in the wet and dry zones. It is commonly used of fertilizer and proper water supply.

Solidex and Solonetz soil

This kind of soil is abundantly found in areas such as Damana and Tamankaduwa. Suitable for paddy and grasses.

Problem in utilization of soil and methods of conservation

Problem

1.Severe soil erosion.
2.Salinity of soil.
3.Reduction of the capacity to retain water in soil.
4.Reduction of fertility due to over exposure of land.
5.Land degradation due to chemical fertilizer, pesticides and weedicides.
6.Occurrence of natural disasters such as floods and landslides.
7.Effect on the ground water stores.
8.Soil organisms get destroyed.

Methods of conservation of soil

1.Select crops following the agricultural principles and manage accordingly.
2.Regulating the use of fertilizer and improving the consumption of organic fertilizer.
3.Cultivating cover crops.
4.Turn over the soil according to contour lines in slopes.
5.Stripe cultivation method.
6.Use crop residues as fertilizer.
7.Use block and spill drains slit drains and green fence. And the use of stone ridges.

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