ABSTRACT:The effect of Ipomea asarifolia on physico -chemical properties of the soils at Usmanu Danfodiyo University, Sokoto main campus, in the Sudan Savanna of Nigeria was investigated. The study determined the effect of the plant on some physical and chemical properties of soils, found out the nutrient retention ability of the plant in the soils and the variation of the effect with distance within the plants canopy. A total of 48 samples were collected from four different sites within Usmanu Danfodiyo University main Campus; VC complex area, University stadium area, Behind new library area and opposite IBB centre area and four distances from the plant (control, plant base, 0.5 m and 1 m from the plant base). Samples were collected for use in a randomized complete block design (RCBD) experiment with three replicates. Soil pH, Organic C, CEC, total N, available P, K, Ca and Mg concentrations were determined, particle size analysis was also carried out. The results were subjected to analysis of variance (ANOVA), where significant F values were obtained, the means were separated by Duncan multiple range tests (DMRT). The difference among the sites and the distances were found to be statistically significant (P < 0.01) for the chemical properties determined. The soils of the University stadium area had the highest CEC and total N; 4.28 g kg -1 and 0.41 g kg -1 respectively, while the soils of the IBB centre area had the least organic carbon, CEC, and available phosphorus; 3.23 g kg -1, 2.00 cmol kg -1 , 9.00 mg kg -1 respectively, with the effect almost following the order; University stadium area > VC complex area > New library area > IBB centre area. On the other hand, the effect on all the parameters was found to decrease with distance from the plant with the base of the plant having the highest organic C, CEC, total N, available P and exchangeable K, Ca and Mg; 6.83 g kg , 0.21, 0.38, and 0.45 cmol kg -1 respectively. The effect was attributed to the accumulation of organic matter around the plant and its ability to prevent erosion by both water and wind thus retaining nutrients making it a suitable cover crop for soil fertility improvement.

The increasing negative effects of hydro carbon fossil fuels on the environment has called for quest for alternative source of energy. Among the renewable energy sources, biogas has been evaluated as one of the most effective, efficient and environmentally benign sources of energy. This study evaluates the flammability of biogas produced from cow dung compared with firewood. The experiment was conducted batch wise in mixing ratio 1:1 at mesophilic temperature under 25 days retention time. Weighing balance was used to measure the cow dung and firewood. Biogas production and firewood flammability were measured using combustibility test in seconds using stopwatch. The total gas yield was burnt and recorded 5,088 seconds (1hour 24.8mins), on average 1kg of cow dung produces biogas that burns for 636 seconds (10.6mins), the gas burnt with clear blue flame revealing the effectiveness of water scrubbing method, while the 8kg of firewood was burnt 8,208 seconds (2hours 28mins). On average 1kg of wood fuel burns for 1,026 seconds (17.1 mins). Comparing the result in term of flammability and efficiency, Biogas could be used as waste management option, generate light and run vehicles and at the same time replace the use of firewood which produces toxic gases that are harmful to health, thus biogas is more efficient.

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