Comparison of three land evaluation systems in capability assessment of soils of coastal plains sand in Southeastern Nigeria

Abstract

Land evaluation systems vary in approach and have not always produced good results outside regions where they were originally conceived. To test the extent of their agreement, Land Capability Classification (LCC), Fertility Capability Classification (FCC), and Suitability Rating were combined in physically evaluating soils of Coastal plains sand, Imo State, Nigeria, using data from 20 pedons. With respect to LCC, soils of inland valleys were limited mainly by wetness, which had 2 out of 6 profiles of the unit classified beyond the arable. The well-drained upland soils, all of which fell within the arable classes, were subject to sheet and rill erosion. By standards of FCC, soils were limited by ‘g’ - water logging; e - low ability to retain nutrients; i - potential fe - toxicity; k - low nutrient capital reserves. Based on suitability rating, soils potentials for agriculture varied from poor to good. Results of LCC and FCC correlated significantly (r = 0.771), but none of these correlated with suitability ratings of the soils. Use of the international systems should be augmented with further soil tests some of which may be got from other comparable systems so as to capture other locally important environmental details. Subjecting factors identified by FCC to suitability rating improved evaluation procedure. Land use in the location did not strictly consider the capability of the land. Cultivating rice to the wet soils or draining them, contour cultivation on slopes, adequate fertilization of soils are recommendations to improve land management.