Studies on Mineralogy, Micromorphology and Relationships of soils along the Sukuma Catena in Maswa District, Tanzania

Abstract

A study was done to characterize major soils in the typical catena soils of Sukumaland. These may be ethnoclassified as lkungu (Haplic Acrisols), ltogoro (Eutric Vertisols), lbushi (Calcic Luvisols), Luseni (Dystric Arenosols) and Mbuga (Calcic Vertisols). Selected typical soils were described and sampled from surface and subsurface horizons for mineralogical, micromorphological and fertility studies. X-ray diffraction studies indicated that the soils have different mineral components in the surface and subsurface horizons. Quartz is the dominant mineral in topsoils of both lbushi and Luseni soils. The subsoils in Luseni soils are dominated by quartz but also and kaolinite clay mineral. Smectite and calcite predominate in the clayey soils (ltogoro and Mbuga). Both the surface and subsurface soils of most lbushi soils are rich in calcite clay mineral. Haematite and kaolinite are dominant in lkungu soils. Due to presence of calcite in Mbuga, lbushi and ltogoro soils, these soils are prone to sodicity problems. Micromorphological data show the absence of interaction between the soil matrix and the weatherable minerals which also indicate that the soils are not formed in situ. However, lkungu soils have shown all characteristics of a soil with parent material weathering in situ. The soils can be grouped into categories of agricultural importance as follows: Luseni soils are infertile with acidity problems, lbushi, ltogoro and Mbuga soils are sodic. lkungu soils have favourable pH and therefore relatively better for agricultural purposes at present. In view of these differences the management of the different groups soils along the Sukuma  catena deserve critical attention, if better agricultural output is to be realised.

Keywords: Sukuma catena, mineralogy, micromorphology, soil management, Tanzania

Tanzania J. Agric. Sc. (1998), Vol. 1, No.2, 109-120