In the fall of 2012, I was still working part time with Iowa State and the newly seeded athletic fields built the previous year were in need of attention for weak, spotty growth. Dr. Dave Minner, myself, and Brent Cunningham (of rec services at ISU) all went over what took place during field construction (an outside contractor built the fields) to try and determine why the newly seeded grass wasn’t growing like it should. The one thing that stuck out to us was the use of compost from the ISU dairy farms that hadn’t been tested prior to application. Using compost is a great way to build soil structure and organic matter, however, if it isn’t completely composted, it can contain high levels of soluble salts harmful to turfgrass growth.
We took a handful of soil samples and sure enough, there were high levels of K, Mg and Na, some of which can hinder plant growth if in high enough amounts. Further, if Mg is found in high enough amounts (> 12%), it can have negative, dispersive impacts on soil due to molecular differences when compared with Ca. We think of Ca as the main building block and Mg as a secondary structural component, required in much lesser amounts.
I was also working part time with Calcium Products during this time knew this field would be a perfect fit for a SuperCal SO4 pelletized gypsum application to reduce the levels of K, Na and Mg in the soil, restore proper cation balance and allow the harmful salts to be leached out. Calcium Products donated gypsum to the school to be applied at a rate of 10 lbs/1000 sq ft. to the two fields.
Recently I was able to visit ISU to see how the fields were progressing after the SO4 was applied this spring. Brent has been very happy with how the fields have progressed after the SO4 application and a modification to his fertility program, which included mostly nitrogen applications since other nutrients were in sufficient amounts, according to our soil tests. I almost couldn’t believe they were the same fields I was on last fall!
Thanks to Brent for cooperating with us on this project. We will take soil samples again this fall and see how the soil chemistry is progressing and likely continue with maintenance applications of SuperCal SO4 in the coming years. Take a look at some photos ‘before’ and ‘after’ the SuperCal SO4 application and modification of fertility.
Fig. 1. A picture taken 6/13/12 showing more spotty growth and areas with no grass growing.
Fig. 2. A picture taken one year after the previous picture, 6/26/13, showing healthy, lush turfgrass, almost ready for play.Fig. 3. A picture taken 7/11/13 showing how healthy the grass looks, thanks to the SuperCal SO4 application and modified fertility program.