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Wei-Ling Yuan, Shang-yong Yuan, Xiao-hui Deng, Cai-xia Gan, Lei Cui, and Qing-fang Wang

application can pose potential adverse environmental and health concerns ( Deng et al., 2012 ; Jing et al., 2007 ) such as groundwater pollution by NO 3 - -N, NH 3 , and N 2 O volatilization into the atmosphere ( Fan et al., 2010 ; Shi et al., 2010 ; Wang

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John M. Skelly, Don D. Davis, and Dennis R. Decoteau*

An Air Quality Learning and Demonstration Center has been developed within the Arboretum at Penn State Univ.. The Center provides opportunities where students (of all ages) and teachers (grade-school through to classes within the Univ.) can learn about air quality as one of our most important natural resources. A seasonally interactive display of air quality monitoring instrumentation, self guided walkways through gardens of air pollution sensitive plant species, innovative techniques for demonstrating the effects of air pollutants on plants, displays of recent research findings, industry supported displays of pollution abatement technologies, and a teaching pavilion are within the Center. A Pennsylvania Dept. of Environmental Protection air quality monitoring station with ozone, sulfur dioxide, nitrogen oxides, carbon dioxide, PM < 2.5 u mass and speciation samplers, and a complete meteorological station provide data on the immediate environmental parameters. These data are relayed to an LCD crystal display board that has been mounted on the outside of the monitoring building; visitors are able to see the various measures of the air quality on a real time basis. Pannier type fiberglass display panels provide understandings of the various facets of air pollution formation and transport phenomena, air quality monitoring methods, the functions of open-top chambers, foliar symptoms expressed by pollution sensitive plants within the bioindicator gardens, and the impacts of pollution on agricultural and forested ecosystems. Handicapped accessible walkways lead visitors throughout the Center to the Teaching Pavilion that easily accommodates 80 persons. The pavilion is equipped with drop down curtains, electric power, and internet connections.

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Lloyd L. Nackley, Elias Fernandes de Sousa, Bruno J.L. Pitton, Jared Sisneroz, and Lorence R. Oki

al., 1996 ). Excessive irrigation creates pollution, is expensive, and promotes disease. Nutrient-laden runoff from nurseries and greenhouses can be a significant environmental concern for both ground and surface water pollution ( Majsztrik and Lea

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Carolyn DeMoranville

contributor to the nutrient pollution, a limit is set on the amount of N or P that can leave the farm and move into the impaired water body. Therefore, in addition to considerations of crop need, nutrient management, particularly that for N and P, must include

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Janet C. Cole, Vicki L. Stamback, and Charlie Gray

Few data are available to indicate the chemical concentration of runoff from nursery operations, and, to our knowledge, no model systems have been developed to gain such data. This paper describes such a model system, in which nursery production beds have been designed to collect and quantify runoff water and contaminant concentrations so that management practices may be identified to decrease potential pollution problems.

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Martin M. Maboko and Christian P. Du Plooy

Africa, with at least 10% to 15% of water and nutrients that leach from the rooting zone with a potential risk of pollution. Further studies need to be conducted on reduced fertilizer application on different growth media, whereas investigating the

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Ashley A. Thompson and Gregory M. Peck

Chesapeake Bay, where agricultural N has become an environmental pollutant. In an effort to reduce N pollution, the Environmental Protection Agency has enacted Total Maximum Daily Load limits on the amount of N that may enter the Chesapeake Bay Watershed

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C. M. Geraldson

During the 1970s a mulched gradient concept was adapted by the Florida vegetable industry and the average yield of tomatoes was doubled. Currently, because of potential water restrictions and society's increasing concerns about environmental pollution, a containerized gradient concept is being evaluated. Containers, media and nutrient/water balance are major components being evaluated to maximize water use efficiency and minimize pollution and, at the same time, maintain or increase the existing competitive excellence. Three seasons of results indicate tomato yields equivalent to those produced commercially; water use has averaged 4 liters/plant/day (about 1/5 to 1/10 that used commercially; and leaching, fumigation and plastic mulches have been eliminated. The concept as a sustainable production system is considered commercially feasible.

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A.K. Alva

Nitrate pollution of surfacial aquifer is fairly widespread in deep sandy soil areas of Central Florida. Since citrus is a predominant crop in this area, despite lack of conclusive evidence suggesting citrus fertilization as the source of nitrate pollution, investigations are in progress to develop Best Management Practice (BMP) recommendations for N fertilization of citrus in an effort to improve N use by the trees and to minimize potential nitrate leaching. Our ongoing studies on both young and mature trees have demonstrated that the use of improved fertilizer formulations and programmed application schedules have facilitated to decrease the rate of N application considerably without any adverse impact on tree growth and/or fruit production while minimizing nitrate leaching below the rootzone. Our approach involves developing BMP recommendations on the basis of iudicious irrigation management and generating database on N removal by the fruits, annual N contribution to the trees by mineralization of organic N, and N losses including leaching, denitrification, etc.

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Nihal C. Rajapakse, Roy E. Young, Margaret J. McMahon, and Ryu Oi

The interest in using nonchemical alternatives for growth control of horticultural crops has recently increased due to public concerns for food safety and environmental pollution. Several research teams around the world are investigating alternative growth control measures, such as genetic manipulation, temperature, water and nutrient management, mechanical conditioning, and light quality manipulation. This review discusses the recent developments in light quality manipulation as a nonchemical alternative for greenhouse plant height control.