Land suitability evaluation for agriculture around Timau area - Heru District

Abstract

A study was conducted of about 8000 ha around Timau area in Meru District to evaluate its land suitability for agriculture. A semi detailed soil survey was carried out to classify and map the different soil units. Based on the relevant land qualities of each Soil Unit and physiography they were seperated in 15 Soil Mapping Units for the various Land Utilization Types with land use recommendations given. The following land qualities were rated and used to assess the suitability of each Soil Mapping Unit: soil water retention, nutrient availability, drainage, soil depth, possibility of mechanization, workability and erosion susceptibility. The following Soils Units were identified in the area: the (rudi-) Mollic ANDOSOLSi the Humic ALISOLS; the Gleyic, Chromic, (rudi-) Dystric, Humic and Eutric CAMBISOLSi Eutric FLUVISOLSi .the Lithic and rudi-Mollic LEPTOSOLS and the (rudi- ) Chromic 4UVISOLS. The soils are developed from intermediate igneous rocks (I) and falls into 15 Soil Mapping Units according to their physiographic positions. The mountain (M) soils comprise of unit MI with rudi-Dystric CAMBISOLS and Mountain Valley Unit M-VI with Lithic LEPTOSOLS The minor hill (H) soils comprised of unit HI with Mollic LEPTOSOLS. Footslope (F) soils comprised of Unit FI1 with rudi -Humic CAMBISOLS, FI2 with rudi-Dystric CAMBISOLS and FI3 with rudi- Mollic ANDOSOLS. The Footridges(R) soils comprised of Units RI1 with Chromic LUVISOLS, RI2 with Humic ALISOLS, RI3 with Mollie ANDOSOLS and RI4 with rudi-Chromic LUVISOLS. Valley(V) soils with Unit VA as Eutric FLUVISOLSi VII as rudi-Mollic ANDOSOLS; VI2 as Chromic CAMBISOLS; VI3 as rudi-Eutric CAMBISOLS and VI4 as Gleyic CAMBISOLS. The following land utilization types were identified: the annual cultivation of Potatoes, Beans-Mangetout-Flowers, Potato-Maize-Beans and Wheat-Maize-Potatoes at low level technology; Wheat-Dairy-Sheep and wheat-dairy at high level technology; Grazing, Grazing-Forestry and Grazing-Wildlife at low level technology. The Units RIl, RI2 and RI3 are suitable for crop growing and grazing. The Unit RI4 is currently unsuitable for agricultural use since it is highly eroded. The Units FII, FI2 and FI3 are suitable for agriculture, grazing, forestry and wildlife. HI, VA, VI2, VI3, VI4 are suitable for grazing and forestry. Units'MI and M-VI were suitable for grazing and wildlife. Unit RI3 was recommended for potato growing. RII for potato-dairy, wheat-diary and beansmengetout- flowers and potato-dairy associations. RI2 for wheat-barley-diary-sheep association. Mapping units FII, FI3 HI, VA, VII, VI2, VI3 and VI4 were recommended for forestry with controlled grazing. MI, M-VI and FI2 were recommended for wildlife with controlled grazing. Physical land attributes are the major criterion for land use recommendation however, socio-economic factors should form an important consideration.