Physical fertility of degraded acid sands in South-eastern Nigeria

Abstract

We evaluated the physical fertility of degraded and undegraded acid sands in Akwa Ibom State, South-eastern Nigeria. The soils were similar in texture, being predominantly sandy, averaging 90.1% in degraded and 89.9% in undegraded soil. Bulk density averaged 1.50g/cm3 and 1.45g/cm3, while macropores averaged 0.215cm3/cm3 and 0.228cm3cm3 respectively. Saturated hydraulic conductivity averaged 1.43m/d in degraded and 3.25m/d in undegraded soil. Water stable aggregates (WSA) > 2.0mm diameter averaged 31.6% in degraded and 51.2% in undegraded soil, while plant available water capacity averaged 5.94cm/cm and 10.3cm/cm, respectively. Organic C average 0.80% in degraded and 1.59% in undegraded soil. The respective average values of the infiltration characteristics are: sorptivity, 18.0mm min-½and 20.6mm min-½; transmissivity, - 3.0mm min-1 and 2.57mm min-1; infiltration rate at 1 minute, 9.0mm min-1 and 13.0mm min-1, and at 2h, 5.42mm min-1 and 8.33mm min-1; and cumulative intake 650.0mm and 884.0mm. The lower values of the measured properties in degraded compared with undegraded soil indicate the loss of physical fertility in the former. Nigerian Journal of Soil Science Vol. 15 2005: 102-108