Soil Drainage Topography Overlay Process

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4.2.3 Soil Texture

The Map of Tanah Semi Detail from BBSDLP classified the soil textures and soil drainage. Figure 11 shows soil texture for rubber in Banyuasin Regency. Figure 11 clearly described the highly suitable area S1 in yellow color, moderately suitable area S2 in blue color, not suitable area N in young blue color. It was found that about 14.6 of Banyuasin Regency is highly suitable S1; about 65.7 is moderately suitable S2; and 19.4 is not suitable N for rubber plantation . Figure 11 Map of Soil Texture in Study area

4.2.4 Soil Drainage

Spatial data consist of soil drainage including 1 well drained, 2 moderately well, somewhat poorly drained, 3 somewhat excessively drained, 4 poorly drained, excessively drained Figure 12. 37 Figure 12 Map of Soil Drainage in Study area The soil drainage is in the study area are distributed in three classes e.i about 9.89 is highly suitable S1; about 6.77 is moderately suitable S2; and 82.99 is not suitable N . There are dominated by poorly drained, excessively drained or not suitable N.

4.2.5 Topography

Elevation and slope are two aspects to determine topography suitability. Reduction of air temperature as a function of elevation has an important role in growth and development rubber. Rubber as a plantation plant is suitable in warm temperature. Slope usually expressed in percentage has an influence to drainage and cultivation activity. So, lower slope is more suitable than higher slope. Elevation in study area is S1 200 m and slope is S1 0 – 8, that are topographic conditions satisfy the suitability requirements . 38

4.2.6 Overlay Process

After all suitability data of rubber plantation for each factor are ready, to next step was cropping to overlay all suitability data for climate, soil and topography with similar weight. So, each criterion has similar influence to determine land suitability map. The results from overlay process are parcels that are obtained from intersecting between suitability levels of each factor. The results of this process were used for productivity of rubber analysis. The results from the above overlay process the land suitability map for rubber plantation is obtained. The areas were divided into two parts: highly suitable area S1 in yellow color, and moderately suitable area S2 in blue color. According to The Regional Spatial Planning RTRW of Banyuasin Regency, all areas are not allowed for the use of single purpose. Figure 13 shows the land suitability for rubber plantation in study area. It was found that about 15.4 or 164.20 ha of Banyuasin Regency are highly suitable S1 and about 84.6 or 904.68 ha are moderately suitable S2 for rubber plantation . Spatial analysis resulted to suitable area for rubber and the largest area from the total land is moderately suitable S2. 39 Figure 13 Land Suitability for Rubber Plantation

4.3 Existing of Rubber Plantation