Identification of Soil Type

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5.4.2 Identification of Soil Type

This soil type identification is performed by overlay of watershed boundary and soil map aquired from related agency. The input data would be processed using ArcView 3.3 to get data and layout of rock formation on Buper watershed. Soil type of Buper watershed in accordance to FAO consists of Renzina and Eutric Fluvisol while in accordance to USDA consists of Rendoll and Eutric EntisolInceptisol. The broad of each soil type are rendoll of 11,5 km 2 and inceptisol of 1,1 km 2 . Here is the soil map resulted from analysis: Figure 5.18 Soil Type at Buper Watershed 56 1. Inceptisol Inceptisol, one of the 12 soil orders in the U.S. Soil Taxonomy. Inceptisols are soils of relatively new origin and are characterized by having only the weakest appearance of horizons, or layers, produced by soil-forming factors. They are the most abundant on Earth, occupying almost 22 percent of all non polar continental land area. Their geographic settings vary widely, from river deltas to upland forests to tundra environments. For example, they occur in the Mississippi valley, central Europe, the Amazon region, north eastern India, Indonesia, and Alaska. They are usually arable with appropriate control of erosion or drainage wikimedia, 2011 Inceptisol soil profiles give some indication of clay minerals, metal oxides, or humus accumulating in layers, but such accumulation is not sufficient to classify the soil into an order defined by characteristic surface or subsurface horizons. They commonly are found either with underlying weathering-resistant parent material for example, quartzite or siliceous sandstone or in topographic settings conducive to soil erosion or water logging www.britannica.com, 2011. The central concept of Entisols is that of soils that have little or no evidence of the development of pedogenichorizons. Most Entisols have no diagnostic horizons other than an ochric epipedon.Entisols may have any mineral parent material, vegetation, age, or moisture regime and any temperature regime, but they do not have permafrost. The only features common to all soils of the order are the virtual absence of diagnostic horizons and the mineral nature of the soils Soil Survey Staff, 1999. 2. Rendoll Rendoll composition on Buper Watershed, according to mapping operation result by ArcView 3.3 has the widest, that is, 11,5 km2, therefore it can be said that soil type on Buper watershed is dominated by Rendoll. These are the Mollisols that are of humid regions and thatformed in highly calcareous parent materials, such aslimestone, chalk, drift composed mainly of limestone, or shellbars. These soils have a mollic epipedon that rests on the calcareous parent materials or on a cambic horizon that is rich in carbonates. A few of the soils are so rich in finely divided lime that the mollic epipedon has a color lighter than normal but is nevertheless rich in dark colored humus and is within the limits of a mollic epipedon. Rendolls have a cryic soiltemperature regime or a udic moisture regime, or both. They formed underforest vegetation or under grass and shrubs. 57 Rendolls are the Mollisols that Soil Survey Staff, 1999; soils.cals.uidaho.edu, 2011 : 1. Have a mollic epipedon that is less than 50 cm thick; 2. Have a CaCO3 equivalent of 40 percent or more on the basis of the whole soil, including coarse fragments as much as7.5 cm in size in or directly below the mollic epipedon; 3. Do not have an argillic or calcic horizon; 4. Have a udic moisture regime or a cryic temperature regime, or both; 5. Do not have both aquic conditions and the colors defined for Aquolls. To reinforce the soil type information on Buper Watershed, field observation and sampling are executed according to mapping analysis which has been applied through ArcView 3.3 toward soil type map. Observation and sampling are executed on land opening to recognize the soil and rock layers. According to the history and mineral contents, Rendoll Soil and Inceptisol Soil Type tend to be clay. Clay is an impermeable material that water can not seep through percolation. But clay is a material with high soil moisture, then this layer can be a habitat for some plant species according to the thickness of the soil, while its bedrock is an impermeable rock too Dirmawan, 2011. 58 Figure 5.19 Position of Field Observation and Sampling Figure 5.20 Rendoll Soil Type FS1 Figure 5.21 Inceptisol Soil Type FS2 FS 1 FS 2 59

5.4.3 Identification of Non-Groundwater Basin