Using composts to improve turf ecology
As the Superintendent at North Shore Country Club in Glenview, IL, I became interested in applying compost as a soil amendment after reading about research suggesting it’s many agricultural benefits…Posted Jan 28, 2009
Phase II: Implementation
Based on favorable results after 2 seasons of field evaluation of compost topdressing, we implemented the strategy on all our fairways. During our normal coring of fairways, the process involves the following steps:
- Coring with hollow tines,
- Breaking up the soil cores with a vertical mower,
- Topdressing with compost,
- Mixing the soil with compost as it is matted into the surface with a section of chain-link fence,
- Blowing the remaining tufts of turf and thatch into rough via a three-point hitch blower,
- Picking up debris in the rough with an out-front rotary mower fitted with a bagging attachment,
- Irrigate the area well.
We have been coring fairways like this for several years. Adding the extra step of compost topdressing has not significantly impacted the workload. The cleanup is about the same and we can still get our targeted 9 holes (15 acres) done in one day. (Note: Part of our IPM cultural program is poling, by dragging a chain over the fairways each morning to remove leaf moisture and guttation. This process also manages earthworm casting buildup).
Phase III: Results
The results so far are much the same as in the test plots: improved turf density and color; rapid healing of cored turf; Dollar spot (Sclerotinia homoeocarpa) suppression; increased earthworm castings; and thatch reduction have been observed. We continue to monitor the impacts of compost use on turf and maintain computerized spreadsheets to evaluate our results. In time and continued applications, we hope to document improved soil structure and suppression of other diseases.
Selecting quality compost is key
Selecting quality compost is very important; you have to do your homework. Compost products are not yet standardized, so the challenge is in obtaining consistent, high quality compost. The procedure we use to assure the compost we obtain is optimal for our turf involves a series of tests. We analyze chemical, physical and biological activity.
In the chemical analysis we look for:
- Carbon : Nitrogen ratio <20:1, best at 15:1
- pH at 6.5 – 8.5
- None to trace amounts of ammonium, sulfide and nitrite
- Low concentrations of soluble salts, especially sodium
We strive towards elemental balance and recommended ratios favoring the high side of potassium and calcium. Biosolids need to meet US EPA’s Part 503 technical rule for biosolids. All biosolids tested for coliform and other diseases. Biosolids composted properly have been heated sufficiently to kill viruses, coliform and other diseases. Metals in biosolids are often high and should be considered.
Physically we look for:
- Fine texture < or = 1/8”
- Light, crumbly structure, parent material non-visible
- Moisture at 30-40%
- Dark brown to black in color (caution, dark black compost might indicate the compost was too hot)