Effect of five municipal waste derived composts on a cereal crop
Agricultural soils were amended with five mixed feedstock (four source segregated and one mechanical biological treatment) municipal waste derived composts to investigate the effect on a cereal crop over two years. Composts were applied at two rates to contain either 250 or 500 kg nitrogen ha-1 and compared to a control which received no fertilizer. In year one, three of the composts increased barley yield (by up to 21%), compared to the control (no compost and no fertilizer) and two reduced it (by up to 33%). Application of the municipal waste derived compost resulted in greater nitrogen concentration in the grain and 1000 grain weight but reduced nitrogen uptake and yield. Application of composts had no significant effect on levels of lead, nickel and cadmium in the barley grains. Levels of soil potentially toxic elements were not significantly increased by application of the composts. In year two, all composts gave comparable or greater wheat yields in comparison to the control.