Transdermal clonidine was approved by the US (J Clin Hypertens. 2005;7:558-562)

Research compared handheld and mobile data acquisitions of soil moisture [volumetric water content (VWC)], soil compaction (penetration resistance), and turfgrass vigor [normalized difference vegetative index (NDVI)] of four natural turfgrass sports fields using two sampling grid sizes (4.8 × 4.8 m and 4.8 × 9.6 m). Differences between the two sampling grid sizes were minimal, indicating that sampling with handheld devices using a 4.8 × 9.6 m grid (120–130 samples) would achieve results similar to the smaller grid size. Central tendencies and data distributions varied among the handheld and mobile devices. Moderate to strong correlation coefficients were observed for VWC and NDVI; however, weak to moderate correlation coefficients were observed for penetration resistance at three of the four locations. Kriged maps of VWC and NDVI displayed similar patterns of variability between handheld and mobile devices, but at different magnitudes. Spatial maps of penetration resistance were inconsistent due to device design and user reliability. Consequently, mobile devices may provide the most reliable results for penetration resistance of natural turfgrass sports fields.

No abstract

The present study was conducted to explore the spatiotemporal relationship between several plant and soil properties on two natural turfgrass sports fields comprised of native and sand-capped soils before and after irrigation. Minimal differences in strength of relationship and spatical variability among field properties occurred from before to after irrigation at both fields. A number of significant relationships between field properties were observed overall, although significance did not always result in comparable spatial distributions. Additionally, significant relationships on the native soil field were not always significant on the sand-capped field. Results exemplify that a single, typical irrigation event will not noticeably change the strength of relationship or spatial distribution between field properties. Furthermore, the strength of relationship and its influence on spatial variability between field properties can be site-specific, and soil type plays an important role in this phenomenon. This information is valuable to conduct precision turfgrass management practices for potential improvement in the uniformity of multiple field properties, and also to aid in efficient subsequent sampling for future spatial map creation.

Understanding the role of clipping biomass in nutrient budgets of turfgrass systems is critical to improving N use efficiency (NUE). The objective of this study was to evaluate the effect of mowing frequency on clipping tissue characteristics, N mineralization (NMin, %), and NH 3 volatilization (AV, %) from decomposing 'TifTuf' bermudagrass [Cynodon dactylon (L.) Pers. × Cynodon transvaalensis Burtt Davy] clippings applied to the soil surface. Turfgrass clippings were collected from two research facilities in Athens, GA, at 3-, 7-, 10-, and 14-d mowing intervals (MIs). A subsample of clippings from each plot was ground and analyzed using near-infrared spectroscopy to determine tissue characteristics. Soil from each location was packed into polyvinyl chloride cylinders, treated with grass clippings on the surface or left unamended, and incubated for 90 d. Cumulative evolved NH 3 was trapped, and inorganic N was extracted from each cylinder and analyzed colorimetrically after 90 d. Rates of NMin varied significantly across treatments and locations, making it difficult to generate informed recommendations for reducing N fertilization based on MI. Although dry yield (g m -2 ) and tissue characteristics (carbohydrates, cellulose, and lignin) were found to be significant parameters in predicting NMin, no clear relationship was established between MI and tissue characteristics in this study. More frequent mowing appeared to support more vigorous turfgrass growth through greater net clipping yield and may also decrease AV as a function of smaller clipping yield for unique mowing events. Mowing more than one time per week may be more N-use efficient and promote healthier turfgrass systems overall.