ENVIRONMENTALLY COMPATIBLE CONTAINER PLANT PRODUCTION PRACTICES

Abstract

Environmentally compatible production are conscious efforts to design and retrofit nursery container growing areas to improve irrigation and nutrient efficiency and reduce exposure of ground and surface water supplies to contaminated effluent. Irrigation of ornamental crops in containers can be a very inefficient, using large quantities of water and fertilizer. Irrigation and fertilizer efficiencies are directly related. Even with controlled release fertilizers, improving irrigation efficiency improves nutrient efficiency and reduces water volume and nutrients leaving production beds. Increasing efficiency can be accomplished in many ways. Grouping plant species and container sizes into blocks with similar water requirements improves efficiency. Redesigning overhead sprinkler systems to accomplish uniform distribution across growing beds or replacing worn nozzle orifices can significantly improve irrigation. Low volume / low pressure systems distribute water directly into containers and apply less water in a specific amount of time than overhead sprinkler application and therefore conserves water. Applying irrigation in short cycles rather than long cycles improves wetting in substrates and conserves electrical energy, water and reduces nutrient leaching from containers. Creating microclimates in nurseries to optimize light or reduce container temperatures, disease pressure and crop stress can improve water and nutrient efficacy. Flow of runoff from nursery growing areas must be engineered to slow velocity, filter and contain effluent. Strategies are site specific. Capture, containment and re-cycling of irrigation water has been a common practice in many nurseries in the U.S., as a means to provide adequate water supplies. In areas with sandy soils, some nurseries have developed closed systems where drainage channels and collection basins are lined to prevent nitrogen movement from runoff into shallow ground water. Vegetative filter strips adjacent to beds and containment basins have been installed at nurseries as management practices for reducing contaminants in effluent before water enters recycle irrigation supplies. Routing runoff into wetland plant production areas to mitigate nutrients before recycling irrigation has been implemented in some nurseries. In North Carolina, new rules for the Neuse River Basin, a nutrient sensitive watershed, mandate that agricultural businesses in the watershed develop plans to reduce nitrogen loading into the river by 30% within the next five years. Nurseries and greenhouses will be required to implement best management or maintain 15 m riparian buffer zones adjacent to streams and rivers. The North Carolina nursery industry will employ the Southern Nursery Associations Best Management Practices Guide as a format for reducing nitrogen loss from nurseries.