Dr. Craig D. Stanley

Extension: Soil and Water Science

Dr. Stanley’s overall program involves research and Extension activities to develop improved water and nutrient management practices that encourage water conservation and minimize impacts on ground and surface water quality for horticultural crop production.

This program has focused on providing solutions to the horticultural producers through increased options for maximizing productivity while protecting valuable water resources.

In addition, Dr. Stanley has worked closely with state agencies, such as the Southwest Florida Water Management District, the Florida Department of Agricultural and Consumer Services, and the Florida Department for Environmental Protection, to provide science-based information that can be used for regulatory purposes.

Global Situation 

Natural resources (water, flora, and fauna) contribute significantly to Florida's economy and are important components of the quality of life for many residents and tourists.

At least half of the respondents to a 1999 survey indicated that prevention of water pollution (72%), protecting the marine environment (64%), and conservation of wildlife habitat and endangered species (50%) were "high priority" educational program needs for their communities. However, many issues threaten these valuable assets.

Florida ranks third among states in the number of plants and animals federally listed as being in danger of becoming extinct, and half of all Florida's non-marine vertebrates are declining in number.

Problems caused by invasive, non-native species in Florida, which also rank as some of the most severe in the country, threaten wildlife, habitats, and ecosystems. Because Florida is also one of the most rapidly growing states, expanding agriculture and urbanization contribute unique challenges to natural resource conservation and ecosystem function.

Global Rationale 

The objectives of UF/IFAS Extension activities and programs are intended to promote the continued existence, function, and sustainable use of Florida's natural resources for the benefit of Florida—both today and in the future.

These objectives are met by providing science-based information to people, which:

  1. Develop policies that affect natural resources in Florida
  2. Implement education, management, conservation and restoration actions that influence natural resources and ecosystems in Florida
  3. Consume, enjoy, or otherwise benefit from the existence of natural resources and functional ecosystems in Florida

PRG-1293: Water and nutrient management to minimize detriment impact on surface and groundwater resources Program Situation

Protecting natural water resources (surface or subsurface) continues to increase in importance as increased pressure and competition for use occurs in Florida.

Population growth has created a major impact on the availability (physical or regulatory) of water to agricultural producers. This, coupled with highly visible incidents of nitrate or phosphorus loading into surface water, has increased public awareness of the possible water resource contaminants by irresponsible water and nutrient management by agriculture.

Florida has initiated a BMP implementation program that encourages growers to improve management practices by granting a “presumed compliance” status to growers who adhere to certain BMP’s and can document their use. This presumed compliance gives growers protection against legal action by the state in the event that excessive nutrient loading occurs while they're using these BMP’s.

This is a voluntary program and such has influenced the degree to which growers will participate. This project is aimed at determining the effectiveness of current practices and giving strawberry producers enough information to encourage participation in the program without major alteration of their operations.

Local Situation 

Florida's growers produce the majority of the nation's winter crop fresh strawberries.

With more than 7,000 acres dedicated to strawberries, the Hillsborough County's Plant City-Dover area has long been known as the Winter Strawberry Capitol of the World.

The farm value from strawberries was $140 million in 2002-03, up from $38 million 20 years ago. During that time, strawberry acreage has increased 40 percent, up from 5000 acres.

Strawberry producers are among the most unique agricultural producers in the state and most aggressive in adopting technological improvements.

They were one of first commodities to utilize plastic-mulched raised-bed culture in the 1960's. This allowed for soil sterilization, eliminating weeds, nematodes, soil borne insects and disease. The black plastic raised soil temperature for winter production and inhibited future weed germination. It also kept the berries out of the sand and reduced evaporative moisture loss.

Unfortunately, the plastic mulch also eliminated the possibility of augmenting fertility during the production cycle. Since Florida's strawberry production is during the winter, growers needed to freeze protect on occasion with overhead irrigation.

By its very nature, this procedure wet the beds and leached nutrients from the beds during freeze protection. Since there was no way to determine beforehand the number of freezes to come during a berry deal, growers would tend to fertilize on the high side, so there would be adequate fertility for the berry crop during the entire season.

The advent of microirrigation (drip) allowed growers to place a measured amount of water and fertility at the root zone to mirror the plants needs without over-fertilizing or moisture loss through evaporation.

Drip irrigation has reduced the amount of water needed to produce a crop of strawberries by about half and has reduced the industry's rate of fertility by a third. More than 95 percent of the strawberry industry has embraced this technology.

However, because strawberries arrive as bare root transplants the plants must be established by overhead irrigation. Additionally, the growers still must utilize overhead irrigation for freeze protection as needed. This requires the growers to have both overhead and drip irrigation systems.

To reduce groundwater pumped from the aquifer, over 45 percent of the state's acreage collects surface tailwater from the fields and reuses it. The water conserved through these practices is well documented. As an industry, strawberries are using less water than they did twenty years ago, with forty percent more acreage. However, there is little information on the quality of the water in groundwater, in tailwater, or in surface water discharged from the farm during a storm event.

Dr. Craig D. Stanley

Associate Center Director and Professor, Soil and Water Science