Physical Characteristics of Thatch as a Turfgrass Growing Medium
1980
Hurto, K. A. | Turgeon, A. J. | Spomer, L. A.
Where a substantial thatch layer exists, new roots and stem growth from plant crowns occurs, at least initially, within the thatch. In some turfs, very little rooting may occur in the soil underlying the thatch. Therefore, under these conditions it appears that the thatch serves a greater role as a plant-holding matrix and a growth medium while the soil's role decreases. The objective of this study was to determine the bulk density, total porosity, moisture characteristics, and organic matter contents of thatch and surface soils of thatched and thatch-free Kentucky bluegrass (Poa pratensis L.) sites. The evaluation methods included: 1) the core method for measuring bulk density; 2) air pycnometric determination of total porosity; 3) a modified pressure plate procedure utilizing Tempe cells for determining moisture extraction curves; and 4) organic matter content on the basis of weight loss upon ignition. Bulk density of thatch was significantly lower than soil, but varied between thatch samples depending on the amount of soil within the thatch. Total porosity of thatch samples was not significantly different, but was greater than soil porosity. Moisture retention of thatch at low water potentials was less than the surface soil from thatch-free sites, indicating that most of these pores are macro-size pores. This study suggests that cultural practices, such as irrigation, may need to be modified to sustain aesthetic turf where thatch is a predominant component of the edaphic environment.
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