Evaluation of Fresh and Year-Old Solid Waste Composts for Production of Wildflower and Grass Sods on Plastic

Source of compostable materials and length of composting or aging affect quality of composts and their suitability as media for crop growth. In this experiment, year-old and fresh composts of mixed municipal solid wastes (MSW), agricultural wastes (chicken manure and cranberry pomace), and autumn leaves were evaluated for their capacities to support production of turfgrass and mixed wildflower sods. Composts were laid in 5-cm-thick layers on plastic in outdoor plots. Germination, stand establishment, biomass production, and flowering responses of grass or wildflowers were assessed for each medium. Seed germination and stand establishment were sensitive to factors present in fresh, apparently immature composts of mixed MSW or autumn leaves. Subsequent plant growth was reduced in these compost largely due to poor establishment of stands. The limiting factors were identified as excessive ammonium in the fresh MSW compost and inadequate total N in the leaf compost. Aging of the composts increased their value in sod production by lowering the concentrations of ammonium in the MSW compost and by increasing the concentration of N in the leaf compost. Agricultural compost was N-rich but low in ammonium, and aging of this compost had a lesser effect on plant growth than with the other composts. Flowering of annual wildflowers in the first season and early flowering biennial and perennial wildflowers in the second season was greater in the mixed MSW or agricultural compost than in leaf compost. Bloom of late flowering species was unaffected or only slightly affected by the source of compost in the second season. The results of this experiment show that a fully mature compost is required for production of high quality sods.