A laboratory scale method was used to produce pellets from cassia tora stems with pelletizing temperature conditions of 30, 45, 60, 75, 90, 105 and 120oC under a pressure of 50, 70, 90,120 and 140 MPa. A total of 30 pellets were produced under each condition of production. The physical and chemical properties of the pellets were investigated. The pellets produced under 75oC and 90 MPa were found to have durability 90 %. A Bulk density range of 617 to 619 kgm-3 was measured for all the produced pellets irrespective of production conditions. The pellets produced in the range of 50 MPa/30oC-140 MPa/120oC were found to have a moisture content ranging between 7.18- 9.6 %. Ash content of 4.2 % was achieved using both Thermogravimetry (TGA) and CEN/TC 335 standard. The gross calorific value of the pellet was determined to be in the range of 17.89-18.1 MJ/kg. TGA results also indicates low moisture and ash content and the process of pyrolysis occurred at 137-550oC at 10oC/min heating rate. The activation energies and reactivities determined from TG/DTG curve are 72.01, 106.81 and 88.67 kJ/mol and 1.76 E+19, 5.1 E+06 and 3.92 E+05 for step I, II and III respectively. A water boiling experiment was carried out to evaluate the cooking efficiency of the pellets compared to fuel wood, kerosene and liquefied natural gas (LPG). The energy intensities and energy cost of 1.2, 0.78, 0.56 and 1.36 kJ/g of water and 0.2, 0.7, 0.4 and 0.2 Nigerian Naira (N) were calculated for fuel wood, kerosene, LPG and the pellets respectively. vii An economic analysis of fuel pellet production from Cassia tora stems has been carried out for conditions found in Kano state, Nigeria. The total production cost, for a base case scenario of 5t/h and operating for 270 days a year, is £4/tonne (1094.5 Naira/ton) of pellets. A ‘Willingness to pay’ analysis was also performed using the Contingent Valuation Technique. A structured contingent valuation questionnaire was administered to 420 randomly selected households in the Kano metropolis and Chi-square analysis was conducted on the data collected. The results of the analysis, at a 5 percent (0.05) confidence level, showed that p-values were less than 0.05 (0.05>p) for all the responded variables. It is confirmed, from the analysis, that an inadequate supply of energy is a statistically significant problem in Kano state and households significantly use fuel wood for domestic energy applications. The results also indicated the willingness of households to switch to a new product and were willing to pay a mean amount of £5 (1361.5 Naira) for a ton of the fuel pellets. Properties of the cassia tora pellets were found to be comparable with other biomass fuel pellets. It is recommended that policy and investment should be geared towards fuel pellet production in Nigeria, to address problems of energy poverty and environmental deterioration, and provide a means for further economic development.

The lack of forage resources in the Sahelian region of Mali is a major constraint to food production and food sufficiency. Madiama commune is located in northern Mali, in the Niger Delta region. Three separate experiments were conducted to investigate ways to improve pasture resources and productivity. The first experiment (2003) was designed to investigate the influence of sheep grazing tethered at two different residual heights on botanical composition, forage biomass and animal performance. Young sheep weighing approximately 18-24 kg were tethered for a certain period of time depending on residual canopy height. Two treatments 3 or 6 cm residual height were each replicated 4 times. Animals were rotated based on canopy height and each tethered animal followed an 8 paddock rotation. Measurements included forage biomass, plant diversity, animal performance, and botanical composition. The forage species found on these pastures were primarily Schoenfeldia gracilis, Panicum laetum, Setaria palludefusca, Eragrostis turgida, Eragrostis tremula, Zornia glauchidiata, Tephrosia pedicellata, and Cynodon spp. Accumulated seasonal forage biomass increased while forage quality declined as the growing season progressed. Treatment had only a slight effect on animal weight gains (1 to 3kg season-1). These results suggest that residual height may not affect livestock gain. The second experiment was designed to investigate the potential of Cassia tora (C. tora) which is an invasive weed in the region as a supplemental feed for livestock. Cassia tora was harvested within the Madiama commune and ensiled with or without additives (water and or honey/sugar) for 60 or 90 days. Harvest occurred at the vegetative stage in year 1 and mature growth stage in year 2. Prior to placing the chopped material in the bags for ensiling, sub-samples of fresh C. tora were obtained for dry matter (DM) and chemical analysis (NDF, ADF, CP, IVDMD and TDN). In year 1, the ensiled material/fresh material across treatments and locations had NDF varying from 48 to 56 %/ 56 to 57%, ADF from 34 to 41 %/40 to 42%, CP from 9 to 10 %/9 to 23%, and IVDMD from 53 to 64 %/52 to 54%. In year 2, CP averaged twice as much as year 1 with significantly less fiber probably due to the fact that harvest occurred at the vegetative stage. Addition of water or sugar/honey improved the nutritive values of the ensiled material. These results suggest that C. tora can be a reliable feed source during the dry season. A greenhouse experiment was conducted using various P sources (Tilemsi phosphate rock (TPR), North Carolina phosphate rock (NCPR), Aluminum phosphate (AlP), Iron phosphate (FeP), and Triple superphosphate (TSP) and rates (0, 20, 40, 60, and 80 mg P kg-1 soil). Plants were grown for 10 wks, harvested and separated into above and below ground plant parts. The root and plant material were dried, ground and analyzed for elemental P. The result showed variable P solubility and uptake by the plant. Overall, addition of P resulted in an increase in above ground biomass as well as root mass compared with the untreated control. Field and greenhouse experiments showed that in the Sahel region of Africa where feed resources are scarce 8 out of 12 months a year, anything we can do to increase pasture resources and animal productivity while maintaining a healthy ecosystem, could improve the quality of life in the community. / Ph. D.