University of Florida (Tom Yeager)
Fertilization schedules and fertilizers used in the nursery industry were developed to maintain high levels of constant nutrition in the container. In addition, container substrates hold a limited amount of water and frequent irrigation is needed. Thus, nutrients are likely to leach from containers and be transported in runoff from the nursery site or to ground water. The research program proposes to determine how production inputs, such as irrigation application rates and amount, fertilizer application rates and amount, plant spacing, ambient environment, and plant shape impact outputs, such as plant growth, runoff volume, and nutrient concentrations in runoff. These data or the relationship of inputs to outputs will be used to develop recommendations for optimization of inputs that result in minimum nutrient loss in runoff or to ground water from the outdoor or greenhouse production area.
Concentrations of nutrients in greenhouse and outdoor production nursery runoff water can exceed federal standards. Nutrients in runoff and the volume of runoff water are influenced largely by production inputs, but this relationship is not defined in a concise manner and usable format for nursery operators to use in making management decisions. These relationships of inputs to outputs are being quantified through a series of large-scale experiments where plants are grown under different input regimes and outputs measured. The relationship of inputs to outputs will be modeled so that “what if” scenarios can be tested. The advantage of the model is that a nursery operator can determine the predicted output before implementing the practice (inputs), such as applying fertilizer or altering the spacing of plants.
Data from this research will be important for quantification or verification of the impacts that BMPs used in the nursery have on the natural environment surrounding the nursery and will enable nurseries to cost effectively comply with federal Total Maximum Daily Loading standards being established for nutrient runoff. This will be important as public pressures increase to minimize or verify impact on the environment. Additionally, being able to predict environmental impacts from production practices currently used or proposed by the nursery will save money on inputs and provide information needed when applying for cost share funds available for improving irrigation efficiency or when complying with voluntary incentive programs, such as the statewide BMP effort.