An Evaluation of Greenwaste Compost for the Production of Forage Maize (Zea maysL.)

Results of a three year trial (1995-7) investigating the effect of greenwaste compost on forage maize (Zea mays) production are presented. The trial was carried out on a free draining brown cambisol with a silt loam texture in South West England. The compost was produced in open windrows and sourced primarily from garden residues. Compost was applied at rates of 0, 15, 30 and 50 t ha−1, with and without mineral fertilizer (125 kg N, 27 kg P, 56 kg K) to 48 m2 plots. Treatments were replicated three times in adjacent blocks, with treatment positions allocated on a random basis. Crop yields and meteorological conditions were recorded each year, and soil conditions monitored after the third application of compost. Crop yield, which varied from year to year, showed a positive response to fertilizer, and showed an additional response to compost even when fertilizer was applied. Over the three years of the experiment, the additional fresh weight yield response at 50 t ha−1 greenwaste compost was 30.9 t ha−1, which represented a 75 percent increase relative to the untreated control and 20 percent increase on the fertilizer only treatment. Three annual applications of compost at 50 t ha−1 resulted in a significant increase in organic matter and extractable potassium and magnesium, and a significant decrease in pH. The implications of these results for forage maize nutrition and production are discussed.