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because the difference in elevation between two points is 100 meters apart horizontally is 100 meters on a 45
o
slope.
2.2.2.2 Soil Texture
The texture of a soil is determined by the relative proportion of clay, silt and sand particles. Texture is most easily determined in the field by pressing and
rubbing moist soil between the fingers. Texture classes are: o
Coarse texture: sands, loamy sand and sandy loams with less than 18 clay, and more than 65 sand.
o Medium texture: sandy loams, loams, sandy clay loams, silt loams
with less than 35 clay and less than 65 sand; the sand fractions may be as high as 82 if a minimum of 18 clay is present.
o Clays, silty clays, sandy clays, clay loams and silty clay loams with
more than 35 clay. Good soil texture for rubber plant is clay soil texture, while sandy soil is
adverse. Soil with clay texture has a capacity to hold water and nutrients better than sandy soil texture Yew, 1991.
2.2.2.3 Soil Drainage
Natural soil drainage refers to the average wetness or dryness of a soil and may be a clue to soil permeability. The colors of topsoil and sub soil are clues
to interval drainage. o
Well Drained: Land has hydraulic conductivity medium and water holding capacity is medium, moist, but not enough to wet ground near the
surface. This land suitable for various crops. o
Moderately Well Drained: Land has hydraulic conductivity moderate to somewhat low and water holding capacity is low, wet ground
near surface. This land suitable for various crops. o
Somewhat Poorly Drained: Land has hydraulic conductivity somewhat low and water holding capacity is low to somewhat low, wet
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ground to surface of land. This land suitable for paddy rice and other crops fraction.
o Somewhat Excessively Drained: Land has hydraulic conductivity
high and water holding capacity is low. This land suitable only for some plants that without irrigation.
o
Poorly drained:
Land has hydraulic conductivity low and water holding capacity is low to very low. Wet ground for long time on surface.
The land suitable for paddy rice and some plants other. o
Excessively Drained: Land has hydraulic conductivity high to very high and water holding capacity is low. The land not suitable for crops
without irrigation. Rubber plants require water drainage is well. The flood condition is not
conducive to the growth of rubber plants. Soil drainage range of good well and moderately well is ideal range for rubber plants. At soil drainage is poorly and
excessively drained the growth and production of rubber is very low Thomas, 2008.
2.3 Land Suitability for Rubber Plantation
Land suitability is the ability of a given type of land to support a defined use. The process of land suitability classification is the evaluation and grouping of
specific areas of land in terms of their suitability for a defined use. The principles of sustainable development make land-use suitability analysis become
increasingly complex due to consideration of different requirementscriteria. It includes consideration not only inherent capacity of a land unit to support a
specific land use for a long period of time without deterioration, but also the socio-economic and environmental costs Hananto, 2007.
The concept of sustainable agriculture or farming involves producing quality product in an environmentally benign, socially acceptable and
economically efficient way Addeo et al., 2001 in Hananto, 2007, i.e. optimum utilization of the available natural resource for efficient agricultural production.
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