Fescue growth as affected by municipal compost fertilizer blends

A growth chamber study with Sassafras soil (Typic Hapludults) was conducted to find combinations or blends of composts and fertilizers which would be equal to the inorganic N fertilizer requirement of tall fescue (Festuca aru ndinacea). Soil was amended with four rates of compost to provide 0, 16.7, 33, or 50 percent of the total 300 kg N ha(-1) applied. The remaining N, 10 0, 83.3, 67, or 50 percent was provided by NH4NO3. Composts used were a bio solids compost(BC) or a compost made from both biosolids and refuse(MC). Sh redded hardwood bark (B) and N fertilizer combinations were tested to deter mine the effect of the organic matter fraction in compost on fescue. All co mbinations were compared to 50 percent (N50) to 100 percent (N100) fertiliz er (300 kg N ha(-1) NH4NO3) application rates and to each other. Yield and N uptake from the N83 and N100 were equal. Fescue yields of blends were low er than N83 or N100. The 33 percent biosolids/refuse compost N:67 percent N H4NO3 (MC67) combination had equal N uptake to N83 or N100. Because compost N is only partially mineralizable during the first year, the equality of c ompost:fertilizer treatments to fertilizer alone suggests that other ingred ients than N are benefitting the fescue. Yield and N uptake from blends con taining shredded bark were equal to the N fertilizer alone treatments indic ating that there was no benefit to fescue from the bark (organic matter) ad dition in this study. The data suggest that some composts may substitute fo r a portion of the N requirement of crops.