Interrelationship between Bush Fallow and the Physical and Chemical Properties of “Acid” Sands in Southeastern Nigeria

Abstract

Soil productivity and crop yield have declined in traditional farming systems due to reduction in bush fallow period, resulting from demographic and economic changes. But quantitative data on the current age of the fallow and relationship between length of bush fallow and soil properties are scarce. This paper reports the practicability of the bush fallow system and its effect on the physical and chemical properties of “acid” sands in Akwa Ibom State, Southeastern Nigeria. The results show that the bush fallow period is now drastically reduced, and about 30% of the farmers cultivate their lands after a 4-year fallow, 26% after 1-year fallow, while 13% cultivate after a 3 and a 7-year fallow. The soils were sandy in texture and bulk density averaged less than 1.40g/cm³ among the fallow ages. Non-capillary porosity averaged more than 40% among the fallow ages. Hydraulic conductivity varied from moderately rapid to rapid. Available water capacity was generally lower than 7cm water/cm depth. Water stable aggregates >2 mm diameter were low, averaging less than 30% among the fallow ages. The soils were slightly acidic, and organic carbon content was generally low averaging between 1.90% and 2.24% among the fallow ages. Effective CEC was lower than 6 cmol/kg, and base saturation was higher than 50%. The fallow ages were statistically similar in the measured parameters. Management practices that will enhance soil productivity have been suggested.

Nigerian Journal of Soil Research Vol.5 2004: 32-43