Sycamore Farms, owned and operated by Mike Moore, also cooperated in this program. Mike has tried three mixtures for his compost:
- Dairy manure and vegetable culls (radishes and carrots that were low quality)
- Dairy manure, vegetable culls, and gin trash (material resulting from cotton ginning process that cannot be used)
- Gin trash
 Sycamore Farms, mixture #2 |
At the time of field application, samples of the compost were taken to measure C:N ratio. Measurements of the first mixture were taken. The second mixture had an initial ratio of 14:1 and an ending ratio in the range of 8:1 to 11:1. The third mixture had an initial C:N ratio of 19:1 and an ending ratio of 8:1. The beginning and ending ratios are low in comparison to what the literature recommends. However, other tests show that the end product was of good quality. |
The microorganism population counts, phototoxicity, conductivity, and pH measurements indicate that the gin trash mixture only was the best mixture (Tables 3 and 4).
The microorganism counts in the first mixture were low in all categories except anaerobic bacteria and pseudomonads. Although the anaerobic counts were close to typical range, their populations in comparison to the anaerobic bacteria indicate a moisture content much to high. Therefore, the turning frequency of the compost was too low to compensate for the high moisture content of the dairy manure, radishes and carrots. The same is true of the second mixture. The results of the third mixture indicate the turning frequency was appropriate to allow for aeration throughout the compost windrow.
Yeasts and molds and actinomycete populations were not detectable in the first mixture. Both of these groups were greater in number with more woody (carbonaceous) material. Both groups were within typical range for the second and third mixtures.
The addition of gin trash increased (slightly) the carbon content of the material.
In all three cases, nitrogen-fixing bacteria were not detectable. This was expected because all three mixtures had low C:N ratios, therefore did not need additional nitrogen for decomposition.
The phototoxicity tests indicate that the first and second mixtures were not mature when tested. the third mixture showed little potential to harm plants. Conductivity was high enough in the first and second mixtures to cause some plant injury. In the third mixture, conductivity was in a good range for established plants. No pH measurement was taken for the second mixture. However, the first and third measurements were both slightly alkaline.
Table 3. Composting gin trash only had the best results.
| Parameter | Mixture 1 | Mixture 2 | Mixture 3 |
|---|---|---|---|
| Aerobic Bacteria | 6.7E+07 | 2.5E+07 | 6.3E+08 |
| Anaerobic Bacteria | 2.3E+07 | 3.8E+07 | 7.0E+06 |
| Yeasts & Molds | not detectable | 3.0E+03 | 4.9E+03 |
| Actinomycetes | not detectable | 1.1E+05 | 6.3E+05 |
| Pseudomonads | 1.3E+02 | 2.2E+03 | 7.7E+04 |
| Nitrogen-Fixing Bacteria | not detectable | not detectable | not detectable |
| Mixture | Phototoxicity* | Conductivity | pH |
|---|---|---|---|
| Mixture 1 | 53% | 19.7 | 8.6 |
| Mixture 2 | 17% | 15.0 | No data |
| Mixture 3 | 79% | 2.51 | 8.2 |
In summary, three mixtures were used for composting at Sycamore Farms. The first two mixtures had excessive moisture levels. The first mixture had excessive nitrogen levels as well. The third mixture, although having a low C:N ratio by most standards, resulted in a good quality compost.