A lysimeter study was conducted at the Ohio State University Turfgrass Research Center, Columbus, to investigate NO3‐N leaching losses from fertilized turfgrass. Nitrogen fertilizer treatments were applied to ‘Baron’ Kentucky bluegrass (Poa pratensis L.) seeded and sodded turf established on a Miamian silt loam (fine, mixed, mesic Typic Hapludalf). Treatments included two N sources, urea and resin‐coated urea (RCU); and Two fertilization programs, one that emphasize spring and summer applications (SSF) and the second program that included a late season application (LSF). Both the SSF‐ and LSF‐fertilization programs received 218.2 kg N ha−1 yr−1. The NO3‐N leachate concentrations from seeded turfgrass exceeded those from sodded turf for the first 3 mon. As the turf matured, NO3‐N losses from sod exceeded NO3‐N from the seeded plots. Leachate concentrations were 1.1 and 3.5 mg NO3‐N L−1 for seed and sod turf, respectively, from April 1990 through March 1991. Less rooting in the sodded plots resulted in greater N loss. Annual NO3‐N losses were not affected by N source. During the winter of 1991, significantly (P = 0.05) higher percolate NO3‐N concentrations were recorded from urea‐treated plots (3.66 mg NO3‐N L−1) vs. RCU (2.10 mg NO3‐N L−1), however. Similarly, N programs did not result in annual differences in percolate concentration, but differed during the winter of 1991. Concentrations were 3.37 and 2.39 mg NO3‐N L−1 for LSF and SSF, respectively. The NO3‐N leaching losses from all treatments exceeded the maximum concentration limit (MCL) early in the study. These high concentrations were caused by soil disturbance during establishment. During the 2nd yr, NO3‐N leaching results were more representative of typical turfgrass situations with mean annual flow‐weighted NO3‐N concentrations well below the MCL. Different N sources and fertilizer programs did not result in greater NO3‐N percolate losses compared to unfertilized turfgrass plots.

The spectral quality of solar radiance affects plant growth and development. The purpose of this study was to assess the spectral quality of deciduous shade, coniferous shade, building shade, and full sun in a natural environment common to turfgrass growth throughout a day and throughout a growing season. A spectroradiometer was used to acquire solar spectra in these four environments. Acquisitions were made on an hourly basis from 0730 to 1930 h, biweekly, from vernal equinox to autumnal equinox at The Ohio Turfgrass Foundation Research and Educational Center and from 10 April to 1 July 1997 at The Ohio State University campus. Data were tested for variation in spectral quality between morning hours and afternoon hours in full sun and among full sun and deciduous, coniferous, and building shade. Results indicated that changes in spectral quality occurred between morning and afternoon periods in full sun, but total (red + blue) photosynthetically active irradiance was not affected. Measurements indicated that a deciduous tree and a conifer tree filtered significantly more high activity (red + blue) quanta than a building. Blue irradiance relative to total irradiance increased and red irradiance decreased with increasing shade density. Significant differences were detected between full sun, tree shade, and building shade for blue photoreceptor potential (blue photon flux/far‐red photon flux) and phytochrome potential (red photon flux/far‐red photon flux). Results indicated that relationships among blue, red, and far‐red irradiance that influence many plant responses were affected by both shade source and shade density.

Low‐input sustainable turf (LIST) management represents a resource‐efficient option in maintaining uniform, persistent turf. What species are best suited to such management needs to be established. To this end, 12 hardy species were evaluated for 3 yr in Illinois, Indiana, Iowa, Michigan, Missouri, Ohio, and Wisconsin: crested wheatgrass [Agropyron desertorum (Fisch. ex Link) Schult. ‘Fairway’, ‘Ephraim’, and ‘Ruff’], streambank wheatgrass [Agropyron riparium Scribn. & Smith ‘Sodar’; syn. Elymus lanceolatus (Scribn. & J.G. Smith) Gould subsp. lanceolatus], Canada bluegrass (Poa compressa L. ‘Reubens’), hard fescue [Festuca ovina var. duriuscula (L.) Koch ‘Durar’; syn. F. lemanii T. Bastard], sheep fescue (F. ovina L. ‘Covar’ and common), tall fescue (F. arundinacea Schreb. ‘Alta’), bulbous bluegrass (P. bulbosa L.), alpine bluegrass (P. alpina L.), redtop (Agrostis alba L. ‘Reton’; Agrostis gigantea Roth), roughstalk bluegrass (P. trivialis L. ‘Colt’), colonial bentgrass (Agrostis tenuis Sibth. ‘Exeter’; syn. Agrostis capillaris L.), and buffalograss [Buchlöe dactyhides (Nutt.) Engelm. ‘Texoka’ and ‘NE‐315’]. AH were field‐established and compared at three mowing heights: 3.8 cm, 7.6 cm, and no mowing. Quality ratings were based on uniform persistence. Tall fescue and common sheep fescue were the best and most broadly adapted to LIST. In Iowa, hard fescue, Canada bluegrass, and crested wheatgrass also did well. Colonial bentgrass was best adapted in Missouri. Redtop and roughstalk bluegrass grew better in a north‐south area from Wisconsin through central Illinois to Missouri. The buffalograsses excelled in Ohio and southern Illinois. Over all species, the 7.6‐cm mowing height allowed the best turf quality. Specifically, tall fescue, colonial bentgrass, redtop, and common sheep fescue performed best at the 7.6‐cm mowing height. Covar sheep fescue, hard fescue, Canada bluegrass, and Fairway crested wheatgrass could not maintain persistent stands under the 3.8‐cm mowing height. No mowing resulted in intermediate levels of quality with all species. A 7.6‐cm mowing height would be appropriate for testing species in LIST within the seven‐state region used in this study.

Creeping bentgrass (Agrostis palustris Huds.) turf exposed to shade during morning hours may decline more readily than similar turf exposed to afternoon shade. This study compared the quality and physiological responses of creeping bentgrass turf exposed to morning shade with turf exposed to afternoon shade and evaluated responses of the same species exposed to varying shade densities during the same period. Semipermanent shade structures were placed on a creeping bentgrass range maintained at a 6.4-mm height. Structures provided 6 h of morning shade or 6 h of afternoon shade during the summer solstice. Each structure was covered with either 80 or 100% shade cloth and replicated three times. Control treatments of full sun and perpetual shade were also included. Treated turf was evaluated monthly for color, density, root mass, pigment concentrations, and total nonstructurai carbohydrates (TNC). Regardless of response tested, no significant variation was found between plots receiving morning shade and afternoon shade or between plots in 80 and 100% shade. Canopy temperature, in comparison with air temperature, was 7% greater in morning shade than in afternoon shade, but the relationship between canopy temperatures in full sun and shade did not change during the day. Perpetual shade caused a 38% decrease in color and a 33% decline in density but treatments receiving 6 h of shade did not vary from the full sun treatment. Concentrations of chlorophyll a (46%) and b (50%), neoxanthin (31%), violaxanthin (44%), lutein (34%) declined in perpetual shade compared with full sun. Violaxanthin concentration was influenced by photosynthetic photon flux, suggesting its potential use as a shade stress indicator. S HADE is considered detrimental to turfgrass growth and development. Reduced levels of photosynthetic irradiance result in thinner, more delicate leaf blades (Dudeck and Peacock, 1992) prone to mechanical injury and disease infection. Under shaded conditions, carbohydrate availability is limited due to decreased photosynthetic production and results in reduced stem and root growth, reduced tillering, and poor shoot density. Trees, smaller plants, and structures providing shade also reduce air circulation and increase relative humidity, causing leaf surfaces to remain wet with dew for many hours. These wet leaf surfaces combined with reduced evapotranspiration create a microclimate conducive to disease development. Physiological turfgrass features such as pigment concentrations (Possingham, 1980; Wilkinson and Beard, 1975) and carbohydrate reserve (Voskresenskaya, 1972; Burton et al., 1959) may be affected by shade stress. A reduction in the ratio of

Two field studies, a seeded study and a golf course study, were conducted to compare competition among creeping bentgrass, annual bluegrass, and roughstalk bluegrass when subjected to common weed control practices and foliar applications of iron and magnesium. A research site was selected for the seeded study and divided into 10 whole plots receiving irrigation at either 50 or 100% evapotranspiration deficit. Each whole plot was further divided into subplots receiving one of seven treatments: bensulide, ethofumesate, trinexapac-ethyl, foliar Mg, foliar Fe, foliar Mg plus foliar Fe, and control. The site was seeded to a mixture of creeping bentgrass, annual bluegrass, and roughstalk bluegrass in September 1995, and treatments began in March 1996. Annual bluegrass was reduced 29% in plots treated with foliar Fe and 65% in plots treated with foliar Fe plus foliar Mg. Roughstalk bluegrass was significantly reduced in seeded plots treated with foliar iron (50%), plant growth regulator (75%), and foliar iron plus foliar magnesium (100%). Annual bluegrass and roughstalk bluegrass proportions were not affected by irrigation regime. In a second study, the most effective treatment, foliar magnesium plus foliar iron, was tested on a working golf course fairway and on a practice putting green beginning April 1997 and ending November 1997. Treatments on the golf course fairway and practice putting green were ineffective due to the established, perennial nature of the annual bluegrass biotypes on these sites. Further research is required to improve the efficacy of nutritional treatments on these perennials.