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Reuben B. Beverly, Wojciech Florkowski, and John M. Ruter

3 Department of Horticulture, Coastal Plain Experiment Station, Tifton, GA 31793. This project was supported in part by funding from the Pollution Prevention Assistance Division of the Georgia Department of

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S.K. Braman, J.G. Latimer, and C.D. Robacker

partially funded by the Pollution Prevention Assistance Division of the Georgia Department of Natural Resources.

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Wojciech J. Florkowski, Carol D. Robacker, Joyce G. Latimer, and S. Kristine Braman

partial funding from the Pollution Prevention Assistance Division of the Georgia Dept. of Natural Resources.

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P. Diane Relf and David McKissack

The Virginia Gardener Nutrient Management Education Program addressed non-point, urban-runoff pollution of Virginia's streams, estuaries, and groundwater, and included a calendar aimed at alerting the garden consumer to the connection between overfertilization and water pollution. Over 15,000 calendars were requested.

A survey of calendar recipients was conducted. 1500 persons were chosen at random, a subsequent address check confirmed adequate distribution among the regions of the state. The response rate was 28%. Responses indicated that 91.3% of those surveyed had changed their garden practices in some way because of the calendar. 90% of the respondents indicated that the calendar had shown them a connection between proper gardening techniques and water quality, with 82.2% indicating the calendar had been moderately to greatly successful in showing them this connection.

The 1989 Virginia Gardener Calendar was an effective method of educating garden consumers about the connection between water quality and nutrient runoff, and cultural practices which lessen the need for fertilizer in the home garden.

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Susan D. Day, Paula Diane Relf, and Marc T. Aveni

A multi-faceted extension education program to reduce consumer contributions to nonpoint source pollution by encouraging proper landscape management was initiated in Prince William County, Va., and funded through the USDA-extension service. The program now is being replicated in several counties in Virginia, primarily in the Chesapeake Bay watershed. The program recruits participants through educational field days, advertisement and other means. Educational techniques include one-on-one assistance from Master Gardener volunteers and the use of Extension publications developed for this program. Publications developed include The Virginia Gardener Easy Reference to Sustainable Landscape Management and Water Quality Protection—a concise reference of Virginia Cooperative Extension landscaping recommendations that includes a calendar for recording fertilizer and pesticide applications, IPM, and other maintenance activities. The Virginia Gardener Guide to Water-wise Landscaping, was recently added to supplement the program in the area of water conservation. In Prince William County, over 700 people have participated. Most of those who complete the program report being more satisfied with their lawn appearance and spending less money. Participation also resulted in consumers being more likely to seek soil test information before applying fertilizer. Other effects include greater participation in leaf composting and grass clipping recycling and greater awareness of nonpoint source pollution.

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David A. Grantz and Larry E. Williams

1 To whom reprint requests should be addressed. Dept. of Botany and Plant Sciences and Statewide Air Pollution Research Center, Univ. of California, Riverside. 2 Dept. of Viticulture and Enology, Univ. of California, Davis. The cost of

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Richard C. Rosecrance, Steve A. Weinbaum, and Patrick H. Brown

Contributions of nitrogen (N) fertilizer applications to nitrate pollution of groundwater is an increasing public health concern. In an effort to improve N fertilizer efficiency, a study was initiated to determine periods of tree N demand in mature, alternate bearing pistachio trees. Seasonal patterns of nitrogen accumulation in the branches (i.e. fruit, current year wood, one year old wood, and leaves) and roots were monitored monthly.

Branches from heavily fruiting trees contained almost six times more nitrogen than branches from light fruiting trees by September; a result of the large amount of N accumulated in the fruit. Nitrogen accumulated in the branches during the Spring growth flush and nut fill periods in both heavy and light fruiting trees. Root nitrate and total N concentrations, however, peaked during the Spring growth flush and subsequently decreased during nut fill. The relationship between tree N demand and the capacity for N uptake is discussed.

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C. M. Geraldson

The gradient concept, which has been used to provide nutritional stability in a field orientated full-bed mulch production system, is being evaluated as a component in a containerized concept. Conceptionally, the nutrient/water Input must be synchronized with removal. A built-in water table and a time-clock regulated microirrigation procedure were evaluated as water sources. A reservoir of soluble N-K banded at the media surface was used to maintain and evaluate the nutritional gradient. Container design, choice of media, plant populations and even dual containers are being evaluated and selected to enhance the functional efficiency of the concept. Yields of 6.8 to 13.6 kgs of marketable, above average quality tomatoes per plant have verified the feasibility of the concept. The containerized gradient concept using minimal water with minimal pollution and using the gradient approach to allow a maximum productivity with minimal management, has the potential to become a globally sustainable production system.

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R. Scott Johnson, Harry Andris, and Shanti Handley

Foliar urea sprays offer an alternative to soil applied fertilizers which could greatly reduce the potential for nitrate pollution of groundwater, The approach in the past has been to apply relatively small doses of urea in order to minimize leaf phytotoxicity. Our approach is to apply relatively large doses in the fall when leaf phytotoxicity is not a serious concern. Results on peach trees in the field indicated rapid uptake of foliar applied solutions of 4.3 to 8.8% urea (w/w) (2.0 to 4.0% N). About 80-90% of the urea was absorbed by the leaf within 24 hours. Leaf N levels suggest the majority of this urea was translocated from the leaf into the tree within 1 week despite damage to the leaf. There were no negative effects on flowering, fruit set and production in the following year as long as a very low biuret formulation of urea was used.

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Guanghua Zheng

There was a remarkable growth in China's greenhouse horticulture during the past decade. In 1989, the greenhouse area in China was 22,000 ha, but this figure reached up to 350,000 ha in 1999, about 16 times as large as that in 1989. Currently, the main greenhouse design used for commercial production is the energy conservation type—solar greenhouse—and many growers use eco-organic soilless culture for production. The substrates used for vegetable production are perlite, vermiculite, peat, coal cinder, sand, coir, sunflower stem, and sugar cane stem. Dry solid organic manure is mixed into the substrates before conducting cultivation, and then only water is for irrigation. Growing vegetables in this way improved quality, increased market value, and decreased environmental pollution.