POTENTIAL FOR MUNICIPAL COMPOST TO REDUCE INORGANIC FERTILISER USE IN CROP PRODUCTION SYSTEMS

A 3-year field trial was established in 2009 in Canterbury, New Zealand, to assess effects of different rates of mature municipal compost (0, 25, 50 t/ha) in combination with different rates of nitrogen (N) fertiliser (urea at 0, 33, 67, and 100% of standard rate) on crop production and soil and environmental parameters in an arable cropping rotation. Where N-fertiliser was applied with compost, the dry matter yield of the first maize silage (Zea mays) crop was greater than where equivalent N-levels were applied as compost or fertiliser alone. This apparent synergistic effect did not occur in the following wheat (Triticum aestivum) crop. Applications of compost did not lead to an increase in the leaching of nitrates.