The widespread incidence of soil erosion in the tropics has been identified, though few studies have dealt with specific problems of decline in crop productivity associated with soil loss. An understanding of the influence of surface soil loss on crop yield is necessary in order to find out their effects on performance of crops. Effects of surface soil loss on maize (Zea mays L) seed yield, plant height and leaf area index (LAI) were investigated in poultry and meteorological locations in South Eastern Nigeria. The soil loss depths were 0 cm (control), 3 cm and 6 cm. There were very significant correlations at P = 0.01 (r = 0.94, 0.96 and 0.94) between soil loss depths and leaf area index, (LAI), plant height and seed yield and also at P = 0.01 (r = 0.95, 0.94 and 0.94) between soil removal and LAI, plant height and seed yield in poultry and meteorological sites respectively during the study periods. The significant reductions in these crop parameters due to surface soil loss were because of the reductions of the organic matter (2% and 18%) contents due to soil removal which affected the yield parameters. In comparison with 0 cm (control) at poultry site, yield reductions following 3 cm and 6 cm soil removal were 23% and 55% respectively. Corresponding yield reductions in meteorological locations were 50% and 95%. There were also 6% and 29% reductions in plant height following 3 cm and 6 cm surface soil loss, respectively, while at the meteorological location there were 20% and 85% reductions in plant heights due to 3 cm and 6 cm top soil removal. Leaf area index was also reduced, for there were 43% and 62% reductions at poultry locations and 42% and 94% in meteorological location due to 3 cm and 6 cm top soil removal respectively. The generally poor maize yield on eroded soils, even with NPK fertilizer amendments alone means that this treatment may not restore productivity on eroded areas.
Keywords: surface soil loss, erosion effects, leaf area index, seed yield, plant height, productivity reduction, south eastern soils
Nigeria Journal of Soil Research Vol. 6 2005: 1-8