Maintaining high quality surface and groundwater supplies is a nntional Concern. Nitrate is a widespread contaminant of groundwater. Nibogenous fertilizer applied to turfgrass could pose a threat to groundwater quality. However, a review of the fate of N applied to turfgrass is lacking, but needed in developing management systems lo minimize groundwater contamination. The discussion of the late o i N applied io iurfgsrass is developed around plant uptake, atmospheric loss, soil storage, leaching, and runoff. The proportion ofthe fertilizer N that is taken up by the turfgrass plant varied from 5 to 14% of applied N. Uptake was a function of N release rate, N rate and species of grass. Atmospheric loss, by either NH, volatilh t i o n or denitrification, varied from 0 to 93% of applied N. Volatilization was generally 4 6 % of applied N and can be reduced substpntially by irrigation after application. Denitrification was only found to be significant (93% of applied N) on fine-textured, saturated, warm soils. The amount orfertilizer N found in the soil plus thatch pool varied as a function of N source, release rate, age of site, and clipping management. With a soluble N source, fertilizer N found in the soil and thatch was 15 to 21% and 21 to 26% of applied N. respectively. with the higher values reflecting clippings being returned. Leaching losses for fertilizer N were highly influenced by f e r i i l i r management practices (N rate, source, and timing). soil texture, and irrigation. Highest leaching losses were reported at 53% , The discussion of the fate of N applied lo turfgrass will cover the five major categories of the N cycle: plant uptake, atmospheric loss, soil storage. leaching, and runoff. As illustrated in Fig. I, N can be found in both organic and inorganic forms in the turfgrass HE IMPORTANCE of maintaining high-quality sur-T face and groundwater supplies cannot be overstated. Groundwater accounts for 86% of the total water resources in the contiguous USA and provides Dep. ofFloricullure and Ornamcntal Honiculture. 20 Plant Sckmcs Bldg., llhaca. N Y 14853.
Nutrients in surface and ground water can affect human and aquatic organisms that rely on water for consumption and habitat. A mass-balance field study was conducted over two years (July 2000-May 2001) to determine the effect of nutrient source on turfgrass runoff and leachate. Treatments were arranged in an incomplete randomized block design on a slope of 7 to 9% of Arkport sandy loam (coarseloamy, mixed, active, mesic Lamellic Hapludalf) and seeded with Kentucky bluegrass (Poa pratensis L.) and perennial ryegrass (Lolium perenne L.). Three natural organic (dairy and swine compost and a biosolid) and two synthetic organic nutrient sources (readily available urea and controlled-release N source sulfur-coated urea) were applied at rates of 50 and 100 kg N ha(-1) per application (200 kg ha(-1) yr(-1)). Runoff water collected from 33 storms and composite monthly leachate samples collected with ion exchange resins were analyzed for nitrate (NO3- -N), phosphate (PO4(3-) -P), and ammonium (NH4+ -N). Nutrient concentrations and losses in both runoff and leachate were highest for the 20-wk period following turfgrass seeding. The NO3- -N and NH4+ -N losses declined significantly once turfgrass cover was established, but PO4(3-) -P levels increased in Year 2. Turf's ability to reduce nutrient runoff and leachate was related to overall plant growth and shoot density. The use of natural organics resulted in greater P loss on a percent applied P basis, while the more soluble synthetic organics resulted in greater N loss.
Current soil bulk densitometric techniques lack the precision to detect three‐dimensional changes in density in a nondestructive manner. The x‐ray transmission computed tomography (CT) scanner was evaluated as a tool to determine soil bulk density. This scanner is an advanced tool in diagnostic radiology used to obtain a nondestructive cross‐sectional representation of the human body. Typical accuracy and precision for CT scanners are known for materials like human tissue with a linear attenuation coefficient near water. Machine response was evaluated near the upper limit of the measurement range where denser materials, such as soil, are located.Scanner analyses of soil and glass bead‐air filled sphere samples that varied in bulk density from 0.14 to 1.64 g/cm3 revealed that a positive linear response occurred with increasing density. For the Metea sandy loam soil (Arenic Hapludalfs), this CT scanner was found to have precision in the order of 19 mg/cm3. Spatial resolution or the ability to distinguish between two objects in the scanning plane was found to range from 1.25 by 1.25 by 2 mm3 to 6.4 mm in diameter by 2 mm. The greater resolution was obtained when density within the sample varied greatly. Errors in data can occur as a result of certain machine artifacts; however, many of these can be avoided by relatively simple methods.It was concluded that the CT scanner can be used to determine soil bulk density with good three‐dimensional spatial resolution. This is a potentially promising tool for research in the areas of compaction, soil management, and cultivation.
Moving to smart factories presents specific challenges that can be addressed through a structured approach focused on people, processes, and technologies.
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