Combined waste resources as compound fertiliser to spring cereals

There is increasing awareness of the need for efficient nutrient recycling in food production. Therefore, a pot experiment was conducted to contribute to the development of alternative compound fertilisers with balanced nutrient ratios for cereal production. We compared the (1) fertilisation effects and (2) effects on soil chemistry of four organic nitrogen (N)-and phosphorous (P)-rich waste-based products (WBPs), applied with or without potassium (K)-rich bottom wood ash (BWA). WBPs and BWA were applied at two rates (80 kg N ha(-1) + 35 kg K ha(-1) and 160 kg N ha(-1) + 70 kg K ha(-1)) to spring barley (Hordeum vulgare) in year one and spring wheat (Triticum aestivum) in year two, and the effects were compared with those of commercial mineral and organic compound fertilisers. The K fertilisation effects of BWA were masked by the soil's ability to provide plant-available K during both years of the experiment. Plant-available N was, therefore, the growth-limiting factor for barley in year one, when there were no differences in grain yield between treatments with and without K-rich BWA. The mineral fertiliser equivalent of WBPs was 64-118% for N uptake in barley grain, but can be expected to be lower under field conditions. During year two, wheat yield was determined by the plant availability of P and N. Meat-rich meat and bone meal caused P deficiency at the lower application rate as a result of alkaline soil conditions, whereas the P in BWA appeared to be almost as plant-available as soluble mineral P.