Turfgrass Soils:  Identification and Correction

By Chad Burke—Limestone Springs Golf Course

On Monday, March 4^th and Tuesday, March 5^th the GCSAA sponsored a seminar at the Sheraton Perimeter Park South titled Physical Problems with Turfgrass Soils; Identification and Correction.  The instructors for this seminar were Dr. Paul Rieke from Michigan State University and Dr. Robert Carrow of the University of Georgia.  Topics of discussion included identification of soil problems, management approaches to these problems, and managing common soil problems in the field.

       To begin the discussion of identifying soil problems the instructors first reviewed what makes up a soil.  They went on to discuss how these “ingredients” of soil influence or determine such properties as soil texture, soil structure, bulk density, and particle density.  For example soil texture refers to the amount of sand, silt, and/or clay in soil.  Soil structure refers to how these particles are arranged within the soil.  Bulk density and particle density are both lab tests used to determine the amount and size of pores in a soil.  This as we know will determine how well a soil will drain.

      Topics of discussion in management approaches included soil modification, cultivation, drainage, water management, chemical management, and soil water and gas management.

      Soil modification was sub categorized in to partial and complete modification.  Partial modification dealt with modifying an existing soil with any number of soil amendments, both organic and inorganic.  The most common method of partial soil modification is topdressing.  Complete soil modification is when a soil is removed from a site and a new man-made soil is imported. (i.e. USGA green)  The goal of soil modification is to improve soil structure.

       Cultivation was the second management approach discussed.  Cultivation is defined as a mechanical method for tillage with out destruction of the turfgrass site.  The main objective of soil cultivation is to create macropores.  Once this is achieved one will increase gas exchange between the soil and the atmosphere, increase infiltration and percolation, thus increasing rooting.  Methods of cultivation discussed were solid and hollow tine aerification, verticutting, spiking, slicing, and the use of the hydroject.  The instructors also went in to some of the pros and cons of each of these methods.

       The instructors touched briefly on drainage, as another management practice used to correct or avoid physical problems is a soil.  Obviously the goal of drainage is to remove excess from either the soil surface or soil profile.  With proper drainage one lessens the chance for black layer, compaction, thatch, and algae, just to name a few.

         Irrigation management is another crucial element in correcting and avoiding soil physical problems.  Improper irrigation management causes excessively wet or dry areas.  This will affect soil moisture as well as soil temperatures, soil aeration, and the potential for hydrophobic soil conditions.  The key to good irrigation management is a good irrigation system.  Proper head spacing and placement as well as a system that allows flexibility are things that must be considered when designing and choosing an irrigation system.

         All of the above mentioned practices have the common goal of removing excess water and increasing oxygen levels in a soil.  When these methods are not possible, there are some other tools that can be used to increase soil oxygen.  Some we discussed were the use of subsurface aeration and the use of fans.

         In conclusion, I feel the instructors did an excellent job of discussing a wide variety of soil conditions as well as a broad spectrum of management practices to combat these conditions, without ever getting too specific or technical.  I would strongly recommend this seminar to anyone.