Browsing by Author "Olufayo, A.A."

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    A semi-empirical model for estimating surface albedo of wetland rice field
    (International Commission of Agricultural Engineering, 2007) Oguntunde, Phillip G.; Olukunle, O.J.; Ijatuyi, O.A.; Olufayo, A.A.
    Surface albedo plays a vital role in the evapotranspiration component of the wetland rice water balance. This paper examines the influence of the phenological stages of rice (Oriza sativa) field on observed albedo at a tropical site (Ghana) during the year 2002, with a view to parametrizing a simple albedo model suitable for inclusion in models to estimate evapotranspiration in wetland rice cropping systems. Crop management was similar for the two planting dates used in this study. Measurements were taken from 10 m x 10 m plots within rice fields. Four phenological stages were distinguished: emergence, vegetative, flowering and physiological maturity. Surface albedo (α) was measured and simulated, using a calibrated semi-empirical model, at solar zenith angles of 15°, 30°, 45°, 60°, and 75°. Leaf area index (LAI) and crop height (h) were also monitored. Generally, albedo increases from emergence to flowering for both planting dates but slightly decreases after flowering. The correlation coefficient (r) between α and LAI equals 0.985 and the correlation coefficient between α and h equals 0.908. The composed albedo model adequately predicted the observed albedos with an overall r = 0.946 and mean bias error (MBE) of 0.002. The extinction coefficient of the rice crop albedo was estimated as 0.75. Data presented are valuable inputs in agricultural water management, rice production models, and especially as vital sub-routine inputs in calculating evaporation and transpiration from wetland rice.
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    Water use efficiency of Manihot esculenta crantz under drip irrigation system in south western Nigeria
    (European Journal of Scientific Research, 2009) Olanrewaju, O.O.; Olufayo, A.A.; Oguntunde, Phillip G.; Ilemobade, A.A.
    Field experiments was conducted at Teaching and Research Farm, Federal University of Technology, Akure between November 2006 and November 2007 to find out the water use efficiency under drip irrigation system and effect on the growth and yield of Cassava (Manihot esculenta Crantz). A popular hybrid of cassava TMS 30572 was tried as a test crop. The soil of the experimental site was moderately drained, loamy sand. The experiments were laid out in a 4 X 4 X 2 randomised complete block design (RCBD) consisting of 4 treatments, 4 replicates and 2 varieties using a spacing of (1m x 0.8m) for mechanical harvesting. The results indicated that the highest moisture content was recorded at depth of 40cm during the late stage of tuber development and the highest biomass yield was recorded under full irrigation treatment than in other treatments. The yield of cassava ranged from 21.87 to 14.13 t ha-1 in all the treatments except for the control that has 8.45 t ha-1 while the water use efficiency ranged from 19.18 to 23.63 kg ha-1mm. Irrigation through full treatment registered the highest mean tuber yield of 21.87 t ha-1 while the least tuber yield was associated with the control treatment. The height and stem diameter of cassava also responded higher under full treatment of available water. This study demonstrated that medium irrigation (60% AW) could be best option in terms of water efficiency. Water Use Efficiency of Manihot Esculenta Crantz Under Drip Irrigation System in South Western Nigeria