Rootzone Modification Cancel The title field is required!

1. Heath Puckett

   

   0 posts
   
   11/3/2011 8:11 PM

   We recently submitted undisturbed core samples for physical testing to help identify our greens drainage issues. Well....the sand is too fine, and fails to meet USGA specs. They hold too much water/not enough oxygen, AND a hard oxidized iron layer has developed at the sand/gravel interface impeding the flow of excess water out of the system.
   Just another challenge to growing bentgrass in the South...
   
   Recommendations include utilizing a coarser sand in our topdressing and cultivation procedures to improve aeration porosity, and consider rebuilding them in the future .
   But, my question is HOW coarse of a sand should be used to remediate this problem??
   
   I already use a sand source with over 75% medium and coarse fractions combined. But, since the greens fail to meet USGA guidelines anyway, should I disregard USGA specs, and consider a material with an even higher % of larger particle sizes to backfill aeration holes?
   
   We are pretty aggressive with our core aerification program, although will try to aerify more based on this recent knowledge. I've proposed a drill and fill in the spring, and recommended purchasing a Vertidrain. I have considered incorporating Profile, but the costs are a concern...may consider a blend.
   Convert to Champion? Hmmm...
   Any thoughts or suggestions are appreciated.

   
   
   
   
2. Andy Jorgensen

   

   1 posts
   
   11/4/2011 6:11 AM

   Heath,
   
   We use a USGA straight construction sand during aerification as these particles are coarser than our normal topdressing sand. If your current blend meets USGA specs, then why switch? Consider the methods you are using to get that mix into the profile and modify them. Try to increase the amount of soil removed and amount of new sand put back into the profile by additional aerifications or increasing tine size. The best method I have seen is to core aerify with large(5/8" and larger) tines as deep as possible, clean up cores, water to knock the soil that is bridging the aerification holes down, topdress, let the sand dry completely, then broom until all holes are completely filled. You have to be careful using a tow behind broom too much and may want to consider sending guys out with a cart full of sand and push brooms to hit any areas that aren't completely filled.
   
   The drill and fill method works as well, but is pretty expensive mainly due to the labor involved and the kiln dried sand you have to use. Same with DryJect. Both work great though.
   
   My North course is mainly push-up soil with pockets of clay. They were very inconsistent when I got here. We started a program of using 3/4" x 10" tines on a Soil Reliever twice a year. During this program, we were using about 25-30 tons of sand (slightly more than a truckload) per acre. We would also deep-drill between coring regimes. After the first three years of doing this, the greens became more consistent in drainage and soil profile and now drain very well. At first I was convinced they needed a complete rebuild in order for them to improve. Now I'm looking at just regrassing since we got the soil straight. Recover time during this process isn't much longer than a normal aerification, maybe an extra week.

   
   
   
   
3. Satterwhite Kerry

   
   11/4/2011 7:11 AM

   What lab did you use? A bridging coefficient can be determined by the particle size of your sand and a recommendation can be made on the PSA of a sand that would work with your existing growing medium. I have used Turf Diagnostics and Design in Kansas in the past for these types of issues.

   
   
   
   
4. Jeffrey Scott

   

   8 posts
   
   11/4/2011 9:11 AM

   What lab you use is quite irrelevant. What is really worth investigating is to find the qualified consultant who can interpret the lab data and will work with you through the QC process to find the correct material to fix the problem the FIRST time.

   
   
   
   
5. Heath Puckett

   

   0 posts
   
   11/4/2011 1:11 PM

   Andy, we switched topdressing suppliers three years ago from a finer sand to a coarser sand after testing them (both of which were within USGA specifications). Haven't received clarification from the lab yet on a more specific definition of "coarser" in regards to their recommendations...
   
   That's why I've considered an alternative coarser material to backfill aeration holes that would still be compatible with our current greensmix...if such a product exists that isn't located too far away. I doubt it would work in drill and fill or dryject machines though....that's where the Profile may be considered.
   
   
   Any recommendations for a good consulting firm? USGA Agronomists? ISTRC? We've already invested the money to have them tested once....not sure if management will go for a "second opinion" from another lab, but can't hurt to ask. I want to be aggressive in addressing this problem, and avoid creating any more problems later on down the road.
   
   Thanks again.

   
   
   
   
6. Jeffrey Whitmire

   

   0 posts
   
   11/4/2011 5:11 PM

   Heath,
   
   I have used both Tifton Turf Labs in Georgia and Hummell in New York for a similar situation in the past. I was pleased with both.

   
   
   
   
7. Bill Atkin

   

   0 posts
   
   11/9/2011 7:11 AM

   Ideally your root zone will be half pore space, pore space would be half capillary and half non-capillary. The non-cap is air pores, they are the smallest of the pore space. Larger sand components will hold more water than air, if the drainage in the sub strata is good it will accelerate water movement that may result in improved infiltration and leaching, if drainage is not good they may hold more water. Which has the greater amount of air space a room full of basketballs or pingpong balls?