COUNCIL FOR SCIENTIFIC AND INDUSTRIAL RESEARCH SOIL RESEARCH INSTITUTE REPORT ON THE SOIL RESOURCES OF TAIN DISTRICT, BRONG AHAFO REGION, GHANA (CSIR / WAAPP NO. 017) Project Team: James Kofi Senayah (Leader), K. Abrefa Nketia, Emmanuel Amoakwa, Johnny Awoonor, Anim Boafo, Kwadaso, Kumasi May, 2013 1.0 INTRODUCTION 1.1 Background Information Soil information is basic to several economic sectors such as farming, establishment of pastures, forestry, construction of fish pond, mining activities, etc. Soil maps provide a quick summary of soil information that assists in determining the suitability or potential of an area for any agricultural and other related land-use. They are guides to investors and planning tools for agricultural planners. The work on the Tain District in the Brong Ahafo Region, seeks to provide a more detailed soil and related information that will provide relevant information as input in the preparation of any development plan for the district and also provide quick information on potential agricultural and other landuse areas. Tain District occurs within the Tain River Basin Soil Survey Region of the CSIR-Soil Research Institute. It is a recently created district that requires knowledge on its natural resources to assist in its quest for development and a boost in economic activities. The District is basically agriculturally oriented but has little information on its soil resources due to its remoteness until the recent construction of the Bui dam. Basic soil information which provided the baseline data for this study is the draft report of the detailed reconnaissance soil survey of the Tain River Basin and a soil map (1997) available at the CSIR-Soil Research Institute. 1.2 Location and extent The Tain District occurs within the Tain Basin soil survey region of the CSIR-Soil Research Institute. The Bui dam is found in the district. The administrative capital is Nsawkaw. Other major towns are Badu, Seikwa, Menji, Sabiyi, Banda Ahenkro. Tain District is located in the Brong Ahafo Region. It is bounded in the north by the Bole District with the Black Volta separating them, in the east by Wenchi Municipality, in the west by Cote d’Ivoire and the Jaman North District and in the south by Berekum and Sunyani Municipality. It covers an area of about …….sq km. Map 1. Location of Tain district 1.3 Objectives The objectives of this work are to: describe the morphological characteristics of the soils within the municipality map the distribution of the soils evaluate the soils for the production of major crops in the District recommend fertility improvement measures for the production of major crops in the District 1.4 Method of study Basic soil information was compiled from the draft report of the Tain River Basin (CSIR-Soil Research Institute, undated) and the soil map (SRI, 1997). A digitized base map of the district was prepared with the following overlays: soil map on a scale of 1:250,000, contours from the Survey Department of Ghana, rivers and streams, roads and settlements. Several transects were selected on each soil unit for soil and land use observation and recording. Soil observation was carried out along each transect to ensure that the various soils along the catena or the slope were captured. In the field, the co-ordinates of each observed point was recorded by means of Global Positioning System (GPS). Profile pits were dug, described and sampled for laboratory analyses. The observed points were plotted on the base map in the Arc-GIS software. 2.0 PHYSICAL ENVIRONMENTAL CONDITIONS 2.1 Climate There are two rainy and two dry seasons. The southern part receives an average annual rainfall of 55”(1397 mm) and the northern part about 45” (1143 mm) (Asare, 1961). This is to indicate that the district falls within two climatic zones namely the moist semi-deciduous forest to the south around Seikwa and the Guinea savanna to the north. The rainfall pattern appears to be similar with major rainy season from April to mid July and minor rainy season from mid August to October. The main dry season is from November to March while the minor is mid July to August. The south is differentiated from the north by the amount of rainfall and humidity which is higher in the former. 2.2 Vegetation and land use The northern part of the district supports Guinea Savanna Woodland and the southern part, Mixed Derived Savanna – Forest Vegetation (Asare, 1961). The former consists mainly of mixed tall and high tufted grasses, with frequent trees usually below a girth of 30”. The dominant grasses are Hyparrhenia sp., Andropogon gayanus and in frequently cultivated areas, Imperata cylindrical. The common trees are Terminalia sokodense, Lophira lanceolata, and Hymenocardia acida. In the Derived Savanna, Andropogon tectorum and Sarcocephalus esculentus are common. The river valleys sometimes support fringing thicket and there is a fringing forest along the large streams and rivers. 2.3 Releief and drainage The topography is gently undulating in the savanna area and gently undulating to gently rolling in the Derived Savanna area. The western half is dominated hill ranges and the eastern part by dissected plateau 2.4 Geology The area is underlain by Upper and Lower Birimian (mid-Pre-Cambrian), Tarkwaian (Upper Pre- Cambrian) formations (Asare, 1961). The Birimian is intruded locally by granites. The Birimian is made up mainly of greenstones and schist with quartz veins; the Tarkwaian of conglomeratic schists and quartzites. 3.0 THE SOILS OF THE AREA 3.1 Introduction The soils are developed under the Moist Semi-Deciduous Forest in the south and the Guinea Savanna to the north. The soils in the south are developed over the Lower Birimian phyllite which belongs to the Bekwai – Oda Compound Association. The soils in the Savanna occur on fairly well drained summits, upper and middle slopes. They are reddish brown to brown in colour. They are of three (3) kinds (Asare, 1961). 1. Shallow iron pan soils 2. Gravelly soils 3. Deep, non-gravelly soils Generally, the soils of the Tain District are grouped into the following soil associations (Map 2), 1. Sampa Association 2. Banda Association 3. Debibi Association 4. Drobo Association 5. Foamang Association 6. Bekwai – Oda Compound Association 7. Dumboli Association Each soil association has a combination of the three kinds of soils indicated above but in varying proportions. 3.2 Description of the soils 1. SAMPA ASSOCIATION The area is underlain mainly by phyllites with quartz veins. Two terrain units were identified within this soil association. They are 1. The generally undulating topography with slopes generally between 2 – 8% 2. The moderately steep rolling topography with slopes between 8 and 16%. Soils of the Sampa association are summarized in a table in the appendix. The summary is adapted from the draft report on ‘Soils of the Tain River Basin’. The soils described occur over both category of topography. They are grouped as Upland and Lowland soils UPLAND SOILS Peneplain drift soils Soils encountered on the summits and upper slopes are Duadaso series. Duadaso series (Haplic Lixisol) The soil is deep (140 cm), well drained and non-gravelly occurring on summits and upper slopes. The profile consists of brownish grey to grayish brown sandy loam topsoil of about 15 cm thick. The underlying subsoil is light yellowish brown, sandy clay loam to sandy clay to a depth of about 140 cm where incipient iron pan may be encountered. A shallow profile with ironpan at 82 cm was encountered. Concretionary soils Morle series (Pinthosol) Morle series is a gravelly, moderately shallow soil occurring on upper slopes. The topsoil is 0 – 17 cm dark grey silt loam with very few ironstone concretions. The underlying subsoil up to about 60 cm is brown to yellowish brown clay containing abundant small and large irregular ironstone concretions. Ironpan is encountered at 60 cm. Wenchi series (Plinthic Leptosol) Wenchi series is a shallow ironpan soil occurring on summits and upper slopes. It consists of 0 – 30 cm of gravelly topsoil overlying a thick sheet ironpan. Where erosion is severe, the sheet ironpan is exposed on the surface. This soil only occurs in small patches. It is unsuitable for cultivation. Sampa series (Plinthosol) Sampa series is a deep (>120 cm), well drained, concretionary soil found on upper slopes. The profile consists of a silty clay loam topsoil, about 10 cm thick, which is underlain by strong brown to yellowish red silty clay loam, containing many to abundant ironstone concretions and quartz gravel to depths of over 110 cm. Nsawkaw series Nsawkaw series is a soil containing abundant quartz gravel. It normally occurs on middle slopes. The topsoil consists of silty clay with very few fine quartz gravel. The underlying subsoil is clay which contains abundant fine and coarse quartz gravel. The quartz increases from few to abundant down the profile with few ironstone concretions. Sedentary and gravelly soils Drobo series Drobo series is deep, well drained, gravelly soil found on upper slopes. The topsoil consists of 15 cm thick of dark brown silty clay loam with few quartz gravel and ironstone concretions. The underlying subsoil is reddish brown silty clay loam with many to abundant quartz gravel and few ironstone concretions to about 80 cm. From 80 cm downwards, the quartz gravel is significantly reduced to few with traces or patches of decomposed rock to 120 cm depth. Debibi Debibi series is the brown drainage associate of Drobo series. It normally occurs on middle slopes. Like Drobo series, Debibi consists of about 120 cm of gravel, mainly quartz which merges into decomposing phyllite. The profile consists of brown, silty clay loam with few quartz gravel and iron concretions in the top 0 – 15 cm.