Effect of composts and inorganic fertilizers on spring wheat growth and N uptake

The nutrient availability of composts has to be known for their safe use in crop production. A field study was carried out to assess the effect of a spring application of composts and inorganic fertilizers on spring wheat (Triticum aestivum L. 'Messier') growth and N uptake in eastern Quebec (Canada). The experiment was conducted in 1994 and 1995 on two different soils: a Kamouraska clay (Orthic Humic Gleysol) and a Saint-Andre sandy loam (Fragic Humo-Ferric Podzol). Four composts were applied at rates of 0, 90, 180 and 360 kg total N ha−1. Inorganic fertilizers were applied at rates of 0, 50, 100 and 200% of wheat N, P or K requirements. Treatments in which inorganic fertilizers (IN) were added to composts were also included. Grain yield was increased by N rates whereas composts alone at 90 kg total N ha–1 resulted in lower yields than the control in the first year on the sandy loam. Commercial composts resulted in higher yields than dairy manure composts. Wheat showed no significant response to P and K ...