Dear rekan-rekan PPID,

Minggu ini kita bisa menikmati sajian Kopi Delft dengan topik yang sangat menarik,
mengenai TANAH. Kopi Delft ini akan diselenggarakan pada

Hari/tanggal : Jumat, 10 Desember 2010
Waktu : 16.30 – selesai
Tempat : Ruang B1 Unesco – IHE

Catat di agenda dan Google calendar teman-teman sekalian.

BRING SOIL CLASSIFICATION INTO LIFE

Dwi Setyawan
Dept. Soil Science, Sriwijaya University, Kampus Indralaya Km 32 Ogan Ilir, South Sumatra
Visiting Fellow, Land and Water Development UNESCO-IHE Delft, Netherlands

ABSTRACT

For many of you who have never studied soil science, it is a bit frustrating when intercepts
with soil classification. A basic question is that why we need a soil classification system.
Like other systems for classifying object, e.g. plant, animal, there are main objectives
underlying the establishment of such system. To name some, these are 1) to organize our
knowledge about the object, 2) to enable us to study the object in much more easier and
memorable ways, 3) to utilize the concept for practical management. However, we should
first be familiar with the categories used by the system. Soil classification should be
exercised in line with soil morphology and soil genesis (collectively known as Pedology)
in order to obtain holistic understanding about our soils.

Soil science community in Indonesia has recognized for a long time since late 1960 the
classification system developed by FAO/UNESCO, further adapted as CSR (Centre for Soil
Research) nomenclature. In the same period, a new system has also been developed by
USDA (United States Department of Agriculture), widely known as Soil Taxonomy which is
preceded by some compilations, the last is the seventh approximation. Apart from slight
difference in describing details for every category, we presently use six categories namely
soil order, sub-order, great soil group, sub-group, family, and series in Soil Taxonomy.
Judging from a given name, we can quickly imagine its properties. It is possible because
Soil Taxonomy uses derivative names with particular meaning. The most important key is
the soil order, for examples Entisols (ent from recent meaning newly developed soils),
Ultisols (ult from ultimus meaning final weathering stage), Histosols (ist from histos or
tissue for organic soils). By combining three syllables of soil order, suborder and great group
we can classify a soil (e.g. Sulfihemist, Kandiudult, Sulfaquept) and further infer its
properties.

Meanwhile the CSR and FAO/UNESCO systems put much attention to GSG and Sub-group
equivalent when naming a soil, and thus practically have less in number of soil names
compared with Soil Taxonomy USDA. It is also done by grouping soils into organic soils
(Organosol) and the others (mineral soils). Since these systems resemble similar objects of
observation, it is also practical to provide equivalent names for wider audiences.

Soil classification is almost inseparable from soil survey and mapping activities. A soil
surveyor observes most of soil morphology in the field by drilling or auger, measuring slopes,
recording vegetation and land use that subsequently used for drawing boundaries (delineation)
of temporary (soil) mapping units. Based on this map, representative soil profiles and soil
samples can be located.

With the rapid growing of information and computer technology (ICT) coupled with the
advancing geographical information system (geospatial) also trigger the need of integrating soil
classification with other fields of sciences. Some current trends and examples exhibit interest
in soil information, hydropedology, pedometrics/ pedotransfer, and soil algorithms. However,
state of the art and the fashion remain with you as a soil scientist.