A detailed soil survey of ACRBD-4 block, 760ha, of Muda Irrigation Area was carried out in 1981 off season. Based on the constitution of profiles, soils were divided into 4 mapping units, that is, A, B, C and D-soils, and mapped on a scale of 4 inches to 1 mile (1 : 15,840).
　A-soil is comparatively well drained soil. As its plow sole is shallow and stable, its suitability for mechanized farming is relatively high. The soil may belong to a subgroup of Tropaquept not yet defined, an intergrade of Sulfic Tropaquept to Typic or Vertic Tropaquept, and is similar to so-called para acid sulfate soil. The soil occupies higher topographic sites, covering an area of about 100 ha, 14 % of the total area.
　C and D-soils are poorly drained soils. They are characterized by low strength and stability of plow soles and weak development of structure. Therefore, drainage facilities are necessary for advancing mechanized farming on these soils. Their distribution is restricted to depressed sites, occupying as a whole about 100 ha, 14% of the total area.
　B-soil is an intergrade of A-soil to C-soil. For this soil also improvement of drainage is desirable. The area occupied by this soil is about 110 ha, 15% of the total area.
　Consequently total area having need of drainage facilities is estimated at about 210 ha, 29% of the total area of the block.