SportsTurf provides current, practical and technical content on issues relevant to sports turf managers, including facilities managers. Most readers are athletic field managers from the professional level through parks and recreation, universities.
Issue link: https://read.dmtmag.com/i/442256
www.stma.org January 2015 | SportsTurf 15 the trenching process for the 2-inch per- forated drain pipe covered by pea gravel then about 1 foot of coarse sand to the existing grade of the field, once com- pacted. All of the existing soil was removed to an offsite location and replaced by the new pea gravel and sand. Once the 2-inch drains were con- nected to the main trunk line, the process began of installing the 2-inch slit drains perpendicular to the newly installed per- forated lines and the field's natural slope, consisting of 2-inch slits, 8 inches deep on 20-inch centers, filled with the same coarse sand as covering the pipe. All back filling of sand was completed in lifts and the addition of water while compacting was a key element in reducing settling after construction. Once installation was completed we ran irrigation for several days to flush the sys- tem, then soil tests from the outfield were compared to tests from a little more than 2 years earlier. Key factors of soil chemistry and nutrient availability are ECe (a direct measure of salinity through electrical con- ductivity), levels of sodium in parts per million and Cat ion percent saturation. As a result of being able to flush the soil water system into drainage, even with what by potable standards is high sodium irrigation water: ■ The relative salinity was reduced by 88%. ■ Sodium is high in our water and has three detrimental effects. One being it domi- nates the Cat ion sites so aggressively other nutrients aren't available to the plant; second it can cause the soil to lose a desirable struc- ture effecting water movement resulting in poor root structure; and third its dissolu- tion into the water reduces root uptake of moisture. Sodium concentrations after one summer of flushing were reduced by 78%. ■ Finally, Cat ion saturation percent- age measures plant nutrients with similar charges relative to one another and it requires a healthy balance of nutrients. Cations such as potassium, magnesium and calcium are necessary for healthy plant growth and sodium competes for the same soil nutrient holding sites. The sodium percentage relative to 2 years ago was reduced by 50%. In aggregate, very positive signs the soil chemistry system is moving in a beneficial direction as a result of leaching the unde- sirable elements from the soil into the new drainage system. It would preferable to have good drain- age installed at installation and here are key thoughts on drainage construction: Have all soil partials reviewed to make sure they work well together so the sand doesn't infiltrate into the gravel or the gravel doesn't clog the perforated pipe. Sock, a fabric covering for perforated pipe, is not recommended. The distance between pipe and sizing of main drain pipe should be well thought out; if you are going to go to this expense and field down time don't try to save a few dollars by stretching the distances between lateral drains or under sizing pipe. If you must wait for drainage or are thinking of installing into an existing field, plan on 3 months of having the field out of commission and know that the field likely will need seed or sod, so take that into consideration during the budget- ing process. This was very disruptive and the loss of field use was painful for our program but due to years of intensive fertilizer use, poor quality irrigation water due to evapotranspiration left behind increasing levels of sodium, a poorly functioning drainage system, and virtually no percolation into the underlying native soil our challenges in poor physical and chemical properties of the soil preve nted us from growing a healthy turf. ■ ST Ron Hostick CSFM, CGM is the Manager of Landscape Services at California Polytechnic State University San Luis Obispo. The project described in this article was completed while he was the lead groundsworker for athletic areas at San Diego State University, on Smith Field at Tony Gwynn Stadium. The installation was completed during June 2013; the contractor was Green One Industries.