The soil-land use system in a sand spit area in the semi-arid coastal savanna region of Ghana:development, sustainability and threats

The development and sustainability of a horticultural system at the Keta sand spit in south-eastern Ghana is described and discussed. The main crop is shallot grown on pure sandy soils in a semi-arid climate. It is a cash crop system highly dependent on a substantial input of manure and irrigation water from a shallow aquifer. The investigation comprises soil profile descriptions and analyses on the dominant soil type on the sand spit, measurement of electrical conductivity of well water and in the soil, crop experiments and interviews of farmers for local knowledge. The findings show that the farmers have developed a very intensive horticulture system on soils with low nutrient contents and low water holding capacity, and in a climate with a long drought period and a short period of about 3 months where percolation takes place recharging the fresh water lens.West African Journal of Applied Ecology Vol. 13 2008: pp. 132-14

Influence of the inter tropical discontinuity on Harmattan dust deposition in Ghana

The Harmattan is a dry dust-laden continental wind, and in the boreal winter Harmattan dust plumes affects many West African countries, including Ghana. When the Harmattan is strongest the southern part of Ghana is affected by the Inter Tropical Discontinuity (ITD). In this study, we investigate if the ITD functions as a barrier, preventing long transported Harmattan dust to settle south of, and below, it. This is done by analyzing a Harmattan dust outbreak, mapped using Earth observation (EO) data from the Spinning Enhanced Visible and Infrared Imager (SEVIRI) onboard the Meteosat Second Generation (MSG) platform, coupled with data from West African AERONET stations, and comparing these observations with wind data from NOAA's Air Resources Laboratory (ARL) program and the mineral suite of samples from seasonal dust deposits in north and south Ghana. In northern Ghana traces of minerals indicate a weak influence of particles from an arid environment, which is found consistent with the mapped dust plumes and NE wind directions. In southern Ghana the mineral composition show no sediments of an arid origin, the mapped dust plumes is less intense, and the surface wind directions and wind mass trajectories are more varying with lower wind speeds. Based on the results of this study it is concluded that dust deposited, or measured near ground, in the Harmattan period under the ITD, and south of it, does not contain material from the Chad Basin due to the local winds conditions