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Author(s): Agbai Williams P., Kosuowei Mouna T., Efenudu Ufuoma I..

Volume/Issue: Volume 5 , Issue 1 (2022)

Abstract:

The study aimed to determine the effect of different land-use systems on soils in Yenagoa and Southern Ijaw Local Government Area of Bayelsa State. Four land use types were considered namely Fallow land, virgin land, oil palm plantation, and plantain plantation. Soil samples were randomly collected at three depths (0-15, 15-30, and 30-45cm) from three locations in the respective land-use types. The samples were bulked and prepared for the determination of some chemical properties. Core sampling was done to determine bulk density, porosity, and saturated hydraulic conductivity. A double-ring infiltrometer was used to determine the infiltration rate and cumulative infiltration. Sorptivity and transmissivity were determined from Philip’s infiltration model. The research revealed that the soils were acidic with a pH range of 4.4-4.7. There were differing levels of organic matter amongst the lands, the progression was Virgin (43.33g/kg)> oil palm plantations (34.67g/kg)> fallow land (23.33g/kg)> plantain plantations (14.67g/kg). The sand fraction dominated the various land-use systems, having loamy sand in the plantain plantation, sandy loam in the oil palm plantation and fallow land, and a range of sandy loam to sandy clay loam in the virgin land. Cumulative and infiltration rates were measured at an interval of 1, 3, and 5 minutes. The infiltration rate was slowest at the oil palm plantation (PPT) with an average cumulative infiltration of 36.3cm, and highest at the virgin land (VVL) at 67.4cm. The average cumulative infiltration of 42.2cm and 53.3cm were in the plantain plantation (OPT) and Fallow land (FFL). VVL>FFL>PPT>OPT was the progression from highest to lowest. Bulk density across the four land-use types did not exceed the critical level of 1.63g/cm3. The highest gravimetric moisture content of 25% was found in the virgin land > oil palm plantation (24%) > (fallow land) 21.6% > plantain plantation (20.3%). The virgin land had the highest sorptivity (64.5 cm/hr) while the oil palm plantation had the lowest (39.9 cm/hr) - VVL (64.5cm/hr) >FFL (55.6 cm/hr) >PPT (43.1 cm/hr) > OPT (39.9 cm/hr). Transmissivity was lowest (2.4 cm/hr) in the plantain plantation and highest (4.0cm/hr) was in the fallow land. Oil palm plantation and virgin land had transmissivity of 3.7 and 2.8cm/hr. The research showed that there were considerable impacts of land use on infiltration capacity. Soils of natural vegetations would easily support irrigation activities due to their organic matter content and should, therefore, be conserved or utilized with conservative measures, while cultivated lands should be improved regularly.

Keywords:

Land-Use Types, Infiltration Rate, Cumulative Infiltration, Sorptivity, Transmissivity

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