Beginning C/N: 29:1 |
Materials, from Turf Paradise Race Course, include horse manure and straw. For one racing season (September through April) Sunfresh Farms receives approximately 9,000 tons of compostable material. For the first six to eight weeks the windrow is turned on average twice per week. Next, the composting process slows to infrequent turning for another two months to ensure that no nitrogen will be removed from the soil after field application. |
Initial testing of the compost suggests the material from Turf Paradise does not need additional material. The ratio of horse manure to straw is suitable for the compost process. Microorganism populations of six functional groups were tested (below). Five of the six functional groups showed strong population. Nitrogen fixing bacteria were low which was expected due to the high nitrogen content of the manure.
| PARAMETER | RESULT |
|---|---|
| Heterotrophic Bacteria (Aerobic) | 1.5E+07 |
| Anaerobic Bacteria | 1.7E+06 |
| Yeasts and Molds | 4.2E+02 |
| Actinomycetes | 8.5E+03 |
| Pseudomonads | 9.9E+03 |
| Nitrogen Fixing Bacteria | below detection limits |
Arnott Duncan, owner and manager of Sunfresh Farms, reports that the most important factor in the arid southwest is water. Therefore, he schedules turning according to moisture content. At approximately 60% moisture, he will turn the windrows and add water.
Arnott has estimated that the cost of the composting process is approximately $10-$11 per ton. Most of the material is composted during the winter months. Composting during the summer months is more expensive because high temperatures lead to increased water use in the process. For the compost process to be cost effective, the financial benefits must be higher than the process costs. This analysis is beyond the scope of the program.