Soil Museum Thailand Thailand is regarded as an agricultural country. Soil is a fundamental agricultural resource that plays an important
role in the growth of our country's economy. Soil is not simply dirt under our feet. It is a life support system for plants and organisms that lie the bottom of food chain. Soil is obviously the
necessary medium for terrestrial plant life asnd nutrients. What does soil does that makes it so important and unique? Find out!...answers to your questions in our Soil Museum...
What is soil? Soil is a natural body on the earth's surface which has been formed by combinding weathered rock minerals and
decomposed plants (organic matter). It is a mixture of solids (minerals and organic matter), water and air that occur in greatly varying proportions. The properties of soil continuously change
with time and differ from place as result of many natural and anthropogenic factors known as soil forming factors: climate, and living organisms (including human impact), natural slope,
weathering of parent rock material. Soils as a product of these various soil forming factors have large differences in their mrphology, fertility and behavior for a wide range of uses.
Background of soil survey... Soil survey and classification was first carried out in Thailand in 1935. The first general Soil Map of Thailand at scale
of 1:2,500,000 was prepared and published in 1963. In the beginning, soil survey activity was acattered among different departments. Later,soil survey and classification were transferred to
the Land Development Department after its establishment in 1963. A soil map of Thailand (scale of 1:2,500,000) as well as the USDA Soil Classification System (1938) was introduced to be
adapted to soil survey work in Thailand. The detailed reconnaissance soil survey at provincial level began in 1979 and subsequent soil surveys at other intensities have also been carried
out.
Soil of Thailand Soil in Thailand are classified using national system of the US Soil Taxonomy by United State Department of
Argricultures. The current version of the system has six levels of classification in its hierarchical structure. The major divisions in the classification system are: orders, suborders, great groups,
subgroups, families, and series, respectively.
"Soil Series" is the most homogeneous category in the taxonomy. As a class, a series is a group of soils that has
horizons similar in arrangement and in differentiating characteristics. In general, soil series carries names that are highly recognizable within the local area where the soil series was first officially
recognized. Names of district, towns, provinces, and ,local physical or geographic features are commonly used as soil series, Kula Ronghai soil series. There are approximately 240 different soil
series in Thailand. Moreover, the agencies produced soil management reports classifying 62 groups of soil series to be
used as a manual for solving soil problems.
Problem Soils... Problem soils are soils with properties unsuitable for agricultural use and require special management practices for
productive cultivation. Due to their specific eco-environment, they result in servere environmental degradation if used for general agricultural production.
There are 5 mail soil with servere constraint for agronomic productions: saline soils, acid sulfate soils, shallow soils,
sandy soils and organic soils (peat soils). Moreover, the mountainous soils, where slope are steeper than 35%, are also considered as problem soils due to steepness of the area which results
in erosion and other environmental problem.
The northern parallel ranges the valleys between them provide the catchments and headwaters of four major
tributaries of the Chao Phraya River-the Ping, Wang, Yom and Nan Rivers that drain southward. Between the ranges of the north are valleys and serveral intermountain plains that provide
land for agriculture and settlements. The soil moisture is high and the soil productivity continuous tobe above average for the country. Steep slope of these soils is the main constraint that
effect the agricultural production in this region.
The central plain extends southward from the ranges and valleys of the north to the Gulf of Thailand. This long
and wide plain has deep soils deposited by water as it encompasses the alluvial plain of the Chao Phraya River with its many tributaries, and the surrounding piedmont betts. This rivers system
provides the lower plain with outstanding soil fertility for agriculture compared to than other regions.
The Northeast Plateau in some 200 m above mean sea level at its western edge portion with flat to undulating
terrain. The area of sandy soil that is generated by weathering of the sediments above the Maha Sarakham Formation, occupies about 80% of northeast Thailand. The majority of soils are
coarse sand with low fertility and are susceptible to erosion. Saltaffected soild, sandy soils and skeletal soils are main problem that effect the agricultural production in this region.
The Peninsular South is a continuation western mountains and comprises a number of basins, rivers and coastal
plains that are fertile and habitable. More coastal plains and stretches of long beaches are found on the east coast, whereas the west coast appears to be a submerged coast, with a very
irregular shoreline and many estuaries. Most of soils are low fertility with high leaching condition due to grater amount of moisture and high precipitation.
(อ้างอิงจาก : สำนักสำรวจและวิจัยทรัพยากรดิน)
(Office of Soil Resources Survey and Research Tel. 1760 ext. 5138)
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