World Journal of Agricultural Research, 2017, Vol. 5, No. 2, 88-93 Available online at http://pubs.sciepub.com/wjar/5/2/4 ©Science and Education Publishing DOI:10.12691/wjar-5-2-4 Evaluation of Expanded Black Cotton Soil as a Hydroponics Medium Samwel Nyakach 1,* , Japheth O. Onyando 1 , Seth F.O. Owido 2 1 Department of Agricultural Engineering, Egerton University, Njoro, Kenya 2 Department of Crops, Horticulture and Soils, Egerton University, Njoro, Kenya *Corresponding author: nyakachsam@gmail.com Abstract The traditional system of producing crops using soil (geoponics) is currently facing major challenges resulting in food deficits. An alternative is the adoption of soil-less culture (hydroponics) which is regarded as key in increasing production of vegetables, herbs and ornamentals. The study aimed at preparing a hydroponic medium from black cotton soil and rice husks. This involved moulding, firing and size reduction. The aggregates were evaluated based on dry bulk density and saturated hydraulic conductivity. The optimal conditions for preparing the medium was found to be at 750°C, 30 minutes and 9:1 for firing temperature, time and ratio of black cotton soil to rice husk (on a weight basis). This process resulted in 33% reduction in bulk density from 1.43 g cm -3 to 0.954 g cm -3 while the saturated hydraulic conductivity improved from 0.333*10 -5 cm s -1 to 0.00385 cm s -1 , a value that lies between the ranges of Sandy Loam and Loamy Sand. The process improved black cotton soil into a light weight aggregate medium with reduced bulk density, loose and friable aggregates, easy to drain and having moderate permeability to permit water and nutrient movement. The medium is therefore better suited to grow potted plants under indoor or outdoor conditions. Keywords: hydroponics, aggregate medium, bulk density, saturated hydraulic conductivity Cite This Article: Samwel Nyakach, Japheth O. Onyando, and Seth F.O. Owido, “Evaluation of Expanded Black Cotton Soil as a Hydroponics Medium.” World Journal of Agricultural Research, vol. 5, no. 2 (2017): 88-93. doi: 10.12691/wjar-5-2-4. 1. Introduction The term hydroponics is derived from two Greek words; hydro meaning water and ponos meaning working, thus literally meaning ‘water working’. In practical use, it means growing plants in a water and nutrient solution without soil or ‘soil-less culture’. Soil has simply been the holder of plant nutrients, a place where plant roots traditionally live and a base of support for the plant structure. If the nutrients are availed to plants in other ways, then soil would not necessarily be required thereby limiting its accompanying negative characteristics such as unfavourable compaction, poor drainage, degradation [1]. The technology can be traced back to 1936 when the word 'Hydroponics' was coined by Dr. W.F. Gericke [2]. Commercially, the technology is currently adopted in most countries (mainly in the Western world) to grow vegetables, herbs and ornamentals. Among the leading countries in adoption of the technology are Israel, England, Australia, Netherlands, Spain and Canada [2,3]. In Africa, it has been adopted in countries such as South Africa and Kenya. 1.1 Advantages and Limitations of Hydroponics The following are some of the reasons for the preference towards hydroponics [1,3,7]: 1. Plants grow up to 50% faster than in soil because they have easy access to nutrients and water; 2. Plants become ‘vacation proof’ and ‘neglect resistant’; 3. Nutrients are directly available to plants and do not get bound up; 4. Little or no pesticides are necessary because plants start from disease free medium; 5. Smaller containers can be used because roots can grow without being root bound; 6. Gardening is possible where it would not be normally e.g. rocky areas; 7. Less labour is required because there is no digging or weeding; 8. Better quality products and higher yield due to increased control over growing conditions. However, the technology also experiences some limitations. These include: 1. High initial capital expenditure especially when combined with controlled environment agriculture; 2. It requires considerable degree of management skills; 3. Because of the costs involved, it is appropriate for high value crops; 4. Yields may reduce when the temperature of the solution increases. 1.2. Hydroponic Systems Common hydroponic systems include aquaculture or aquaponics, aggregate culture and aeroponics. Most