Physical and Chemical Properties of Four Contrasting Soils under Different Land Use System

This study was undertaken to evaluate the physical and chemical properties of four contrasting soils under two land use systems. The land use types considered were fallow and cultivated. Four soils from Nsukka Hill (Entisol), Nsukka poultry site (Ultisol), Eha-Amufu (Inceptisol) and Ikem (Inceptisol) in Nsukka area of south eastern Nigeria were used for the study. Soil samples from the 0-25cm depth were collected from cultivated and adjacent fallow lands in the four different locations. The soil samples were air-dried at room temperature and then sieved through a 5.00mm sieve. Two hundred and fifty grams (250g) of the sieved sample were further sieved through 2mm sieve and use for the determination of physical and chemical properties of the soils. The result of the study showed that soils under continuous cultivation have low value in all the parameters assessed compared to the adjacent fallow soils. Continuous cultivation decreased the concentration of organic matter (OM), from 2.08-1.87% nitrogen (N), 0.3-0.17% and phosphorous (P) 4.30-3.80mgkg-1 content in all the soils studied. The pH of the soils measured in water and KCl showed low values in cultivated soils with the range 4.10-4.50 and 3.50-3.70 respectively as against fallow soils 4.60-4.90 and 3.20-4.50 respectively. Exchangeable bases, cat ion exchange capacity (CEC) and Base saturation (BS) of the soils decreased following cultivation except for K in Ikem soils, CEC in Nsukka Ultisol and BS in Ikem Inceptisol. Cultivation increased the exchangeable Al3+ and H+ in the Nsukka Entisol and thus increased the acidity. The result of this study is evidence that continuous cultivation causes depletion of soil nutrients and generally affects the physical-chemical properties of soils. This can be remedied through appropriate management practices based on organic residue incorporation, if agricultural productivity and environmental harmony are to be sustained in these soils for future generation.