Morphology, Genesis, Physico-chemical Properties, Classification and Potential of Soils Derived from Volcanic Parent Materials in Selected Districts of Mbeya Region, Tanzania

Abstract

This study clarifies the morphology, genesis, physico-chemical properties and classification of soils developed from volcanic parent materials of Mbeya Region, Tanzania. Six typical pedons (MWK 01, IFIG 02, MKY 03, MWZ 04, KYE 01 and NDE 01), were identified, described and 33 soil samples analyzed for physical and chemical characteristics. Results indicate that all pedons were very deep, with textures ranging between fine and coarse. Soil moisture retention ranged between low and medium (78-101 mm/m). Some pedons had volcanic ash layers of varying thicknesses and buried 2BC, 2Bwb or 3Bwb horizons, typical of recent volcanic soils. Topsoils had low bulk and particle densities ranging between 0.70 to 1.26 g cm-3 and 1.95 to 2.55 g cm-3 , respectively.

Pedological Characterization of Some Typical Alluvial Soils of Kilombero District, Tanzania

“…On the overall, morphology and genesis of the studied soils were typical of alluvial soil formation. 2) Colour: g = gray; gb = grayish brown; vdgb =very dark grayish brown; vdg= very dark gray; bl = black; yb = yellowish brown; br = brown; pb = pale brown 3) Consistence: Dry: so =soft; sh = slightly hard; h = hard; vh = very hard; eh =extremely hard. Moist: fr = friable; fi = firm; vfi =very firm; efi = extremely firm.…”

“…Yet, soil fertility specialists engaged in transferring agronomic technologies from one area to another require well characterized data of the entire pedon including the subsoil [2]. With regard to availability of such information in Tanzania, there is a big gap between need for pedological soil characterization and actual work that has already been done [2]. It was reported that only 3% of Tanzanian soils were mapped and characterized in sufficient detail [10].…”

“…Most research works in Kilombero Valley were conducted on the basis of studying topsoils to about 20-30 cm depth and recommendations were made in respect of topsoil characteristics [6,8,9]. Yet, soil fertility specialists engaged in transferring agronomic technologies from one area to another require well characterized data of the entire pedon including the subsoil [2]. With regard to availability of such information in Tanzania, there is a big gap between need for pedological soil characterization and actual work that has already been done [2].…”

“…The existing national soil-terrain (SOTER) inventory was produced at a scale of 1: 2 000 000 and this is mostly suitable for planning at national level and not practical for fertilizer and agronomic studies [11]. Efforts have been made by several researchers to map and classify soils in various ecologies in Tanzania [2]. However, not much is known about soils of Kilombero Valley in sufficient detail to allow ranking of their potential for various agricultural and non-agricultural uses and for transferring of technology to other areas with similar ecological conditions in Tanzania.…”

“…It gives clear understanding of soil genesis, morphology, classification and spatial distribution of soils in an area [1,2].…”