Masters Theses

Date of Award


Degree Type


Degree Name

Master of Science


Landscape Architecture

Major Professor

Lloyd M. Callahan

Committee Members

D.B. Williams, W.L. Parks


The purpose of this study was to determine the influence and degradation rate of several commercial and indigenous forms of organic matter in soil mixtures for golf greens. The study included both physical and chemical determinations.

A greenhouse study was conducted to compare bentgrass (Agrostis sp.) responses and disease incidence, media leachate volumes, pH of leachates, and temperatures of media. Samples were tested in a laboratory to determine particle size distribution, organic matter, porosity, bulk density, percolation rate, and cation exchange capacity.

The indigenous organic materials of pine bark, oak sawdust, sewage sludge, cotton chop, and soybean chop compared favorably with the commercial forms of Michigan and sphagnum peats as organic amendments.

There was no apparent serious problems with acidity resulting through the process of decomposition of the media tested.

All of the test media met USGA specifications for porosity and bulk density.

The USGA mix was the only test media to meet USGA recommendations for percolation. All of the other media exceeded the maximum level recommended by the USGA. However, it is known that percolation rates often decrease considerably with time.

No significant amounts of silt and clay were added as a contaminant by the organic amendments tested, except for sewage sludge. Sphagnum peat and pine bark demonstrated the greatest resistance to decomposition throughout the study. Sewage sludge, corn chop, and cotton chop experienced some decomposition during the first 26 weeks, but tended to resist decomposition thereafter. Michigan peat, soybean chop, and oak sawdust decomposed slightly at 26 and 52 weeks. Corn chop provided only a low amount of easily digestible organic matter.

All of the organic amendments showed an increase in cation exchange capacity with pine bark and oak sawdust showing the greatest increase with time.

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