A 3-year study was conducted in Auburn, Ala., on an established hybrid bermudagrass [Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt-Davy `Tifway'] stand maintained at a 2.54-cm mowing height. Treatments were level of soil traffic applied via a weighted golf cart to produce turf and soil that received varying amounts of traffic. Dormant bermudagrass was overseeded with perennial ryegrass (Lolium perenne L.) each October, which remained until May of each year. Spectral data were collected monthly using a multispectral radiometer. Percent reflectance data were acquired over 512 discrete wavelengths in visible (VIS) and near-infrared (NIR) ranges. Quarterly data collection included soil penetrometer and bulk density measurements to a depth of 15 cm. After 2 years of traffic, both soil penetrometer and bulk density data indicated statistically significant increases in soil compaction. In general, as traffic increased there were also increases in percent reflectance in the VIS range. Data were subject to temporal variation, however, as values changed with the date of sample collection. The NIR reflectance data provided little consistent correlation to measurements of soil compaction. Use of NIR and VIS radiometry to evaluate turf stress showed some potential, but temporal variation must be considered.
E.A. Guertal and J.N. Shaw
J.C. Rodriguez, D.J. Cantliffe, N.L. Shaw and Z. Karchi
In the spring of 2001 and 2002, different combinations of media (coarse perlite, medium perlite, and pine bark) and containers (polyethylene bags and plastic pots) were used for hydroponic production of `Galia' muskmelons (Cucumis melo L.) to determine their effect on fruit yield and quality, and their influence on costs of production. Marketable yields obtained for `Gal-152' in the spring 2001 and 2002 were 25.5 kg·m–2 and 39.0 kg·m–2 respectively. When data were combined for 2001 and 2002, fruit yield and fruit quality were unaffected by any combination of media and container. Average soluble solids content was generally greater than 10° Brix. It was determined that the use of pine bark media and plastic pots instead of perlite and bags would save $18,200 per year (two crops)—a feasible option for reducing costs of producing `Galia' muskmelons in greenhouses using soilless culture without loss of yield and fruit quality.