Mitigating nutrient leaching with a sub-surface drainage layer of granulated tires.

Markets for scrap tires have expanded since the early 1990s with the development of value-added applications such as tire-derived fuel and crumb-rubber-amended asphalt. Granulated tires have also displayed the ability to adsorb volatile organic compounds, indicating that the rubber material can be a useful filter media. Sand-based root zones, typically used for golf course putting green and athletic field construction, lack sufficient cation exchange capacity to restrict nitrogen and phosphorus migration through the root zone and into sub-surface drainage systems. Therefore, the adsorptive properties of tire rubber for retaining nitrogen and phosphorus were studied when applied as a distinct sub-surface drainage or intermediate layer in golf course putting greens. A statistically significant reduction in the concentration of nitrate in leachate was achieved by replacing traditional pea gravel with equally sized granulated tires for the drainage layer media, although the mechanism of nitrate mitigation remains unclear. The results indicate that using granulated tires as a drainage layer or fill material beneath sand-based root zones does not compromise the function of the profile or quality of the vegetation while creating an environmentally beneficial and value-added option for scrap tire reuse.

Improvements in horizontality performance as a function of type of training.

90 undergraduates with low spatial perceptual ability were assigned to one of three groups of control, learner-guided instructions, and tutor-guided instructions. The groups differed in amount and type of spatial training administered in a laboratory setting. Participants completed horizontality and vertically spatial perceptual tasks immediately after pretesting and again one month later. Both groups given training showed more accurate performance at posttest than at pretest. In addition, the learner-guided instruction group outperformed the tutor-guided instruction group and control group at posttest and on novel but related tasks. Gender differences in posttest performance favoring males (n = 35) were obtained in the tutor-guided performance group and control group but not in the learner-guided instruction group. The number of hints the latter needed during training was predictive of posttest performance. Implications for assessment and remediation of undergraduates' spatial perceptual abilities are discussed.