Mulching effect of plant residues with chemically contrasting compositions on maize growth and nutrients accumulation

Effects of application of prunings of three woody species (Acioa barteri, Gliricidia sepium and Leucaena leucocephala), maize (Zea mays L.) stover and rice (Oryza sativa L.) straw as mulch on maize were studied on an Alfisol in southern Nigeria in 1990 and 1991. Maize dry matter and grain yield were higher with applications of plant residues and N fertilizer in both years. Addition of Leucaena prunings gave the highest maize grain yield in both years. Compared to the 1990 results, Acioa showed the least grain yield decline among the mulch treatments in 1991. Nutrient uptake was enhanced by applications of plant residues. Leucaena prunings had the highest effect in both years and increased the mean N, P, and Mg uptake by 96%, 84%, and 50%, respectively, over the control. Addition of Acioa prunings increased K and Ca uptake by 59% and 92%, respectively, over the control. High quality (low C/N ratio and lignin level) plant residues enhance crop performance through direct nutritional contributions, whereas low quality (high C/N ratio and lignin level) plant residues do so through mulching effects on the microclimate. Intermediate quality plant residues have no clear effects on crop performance.