FACULTY OF SCIENCE
Permanent URI for this communityhttps://repository.ui.edu.ng/handle/123456789/266
Browse
2 results
Search Results
Item Estimation of bare soil surface temperature from air temperature and soil depth temperature in a tropical station(2011) Adeniyi, M.O.; Nymphas,E.F.Soil surface temperature has critical influence on climate, agricultural and hydrological activities since it serves as a good indicator of the energy budget of the earth’s surface. Two empirical models for estimating soil surface temperature from air temperature and soil depth temperature were developed. The coefficient of determination (R2) of soil surface temperature from the air temperature model ranged from 0.92 - 0.99, while the mean absolute error (MAE) and root mean squared error (RMSE) ranged from 0.5 - 2.48 and 0.77 - 2.630C respectively. For the soil depth model, the R2 value ranged from 0.75 - 0.96, MAE ranged between 1.05 and 4.94, while RMSE ranged from 1.28 - 5.25. Both models performed well on days of year (DOYs), under similar prevailing weather conditions during the model training period.Item Neural network regression for modelling the effects of selected soil physico-chemical properties on adsorption(Nigeria Statistical Society, 2017) Udomboso, C. G.; Nzelu, N.; Olu-Owolabi, B. I.Heavy metals in soils have been known as soil pollutants, to constitute serious economic importance as their accumulation has led to reduced agricultural production and quality of life. In the present paper, we studied the adsorption behaviour of selected heavy metals in soils, due to some physico-chemical properties. The soil under study was obtained from the River Benue Basin in the middle belt region of Nigeria. The heavy metals considered included lead (Pb), zinc (Zn), copper (Cu), and cadmium (Cd), while the physico-chemical properties included hydrogen ion concentration (pH), percentage goethite, percentage humic acid, time, and sorbate concentration. Estimation of the effects was carried out using the statistical neural network at α = 0.05, while the cubic spline was used to interpolate within values and extrapolate forecasted values. Results show that rates of adsorption differ across properties. In all physical properties, except humic acid, Cd is most adsorped at AIC of 0.067, 0.079, 0.002, and 21.137 (all at p<0.05). For humic acid, most adsorped is Zn at AIC of 5.692 (p<0.05). These call for effective soil management system in Nigeria, which is expected to yield reliable data on soil behaviour, as well as concerted effort in eradicating (or reducing) the presence of these pollutants.