Published online by Cambridge University Press: 03 October 2008
Low levels of zinc are reported in flooded rice grown on alkaline clay soils in the Lake Chad basin, north-east Nigeria. Zinc was added at 0, 5, 10 and 20 kg/ha to sample plots. For the untreated plots, the mean levels of zinc in young rice leaf and ‘available’ zinc in the supporting soil, using the alkaline extractant method of Trierweiler and Lindsay (1969), were 18·2 and 0·33 ppm respectively; corresponding mean levels for plots with 20 kg/ha added zinc were 36·5 and 1·54 ppm. There is a correlation between the two variables of r=+0·61 (P<0·01). Levels of nitrogen, phosphorus, potassium, magnesium and calcium in the rice leaf are also reported.