Monday, November 13, 2006 - 10:00 AM

Organic Matter Accumulation in High Sand Content Root Zones.

Tim Vanloo, John N. Rogers III, and James R. Crum. Michigan State University, 640 East Jolly, Lansing, MI 48910

As organic matter accumulates in high sand content root zones the proportion of macroporosity decreases.  This decrease in macropore space can affect water movement within the root zone and decrease turfgrass rooting, leading to issues with turfgrass wear tolerance and performance.   Many cultural practices can help prevent the problems caused by accumulated organic matter, but the factors contributing to accumulation are not clear.  The objectives of this study were to evaluate organic matter accumulation based on root zone type and mowing practice.  A secondary objective was to compare which organic matter analysis method (loss on ignition, Walkley-Black, and Mebius methods) produced the most consistent results on high sand content root zones containing small percentages of organic matter.  The experiment was conducted at the Hancock Turfgrass Research Center at Michigan State University in East Lansing, MI.  The experimental design was a RCBD in a 2 x 2 factorial, with two root zones (well-graded sand and approximately 90 % well graded sand plus 10 % silt and clay) and two mowing practices (clippings removed and clippings mulched and returned).  Soil samples where collected from the experimental plots at three depths (0-2.5cm, 2.54-5.1cm, and 5.1-7.6cm) at 5 months, 17 months, and 22 months after seeding.  Results from the loss on ignition method indicate that organic matter accumulates in the top 2.54cm of the soil at a greater rate than samples at 2.5-5.1cm and 5.1-7.6cm depths, regardless of root zone type.  Results also indicate that mowing practice does not have an affect on the accumulation of organic matter in either root zone.