The objectives of the extension program are to use science-based information to
educate Florida growers about improved soil fertility and water management methods
through publications and presentations of research data and demonstrations of BMPs
so they will be able to sustain yields while protecting water quality.
Specific goals of the extension program encompassing citrus, vegetables, and sugarcane
are the teaching and demonstration of:
- nutrient-related BMPs,
- improved irrigation management and grower decision aids.
Competition of an increasing population for land and water resources has increased
concerns for the environmental health of the watersheds and water bodies throughout
Florida. Therefore, implementation of BMPs designed to maintain or improve water
quality is essential to the sustainability of Florida’s citrus, vegetable and sugarcane
industries. The implementation of these BMPs will greatly impact the local environment
in a positive way. However, BMPs may negatively impact crop production if growers
are not sufficiently educated on how the BMPs should be implemented. Thus, information
on irrigation and nutrient use efficiency is needed by growers to support implementation
of BMPs that will reduce agricultural impacts on the environment and at the same
time reduce production costs for commercially-viable yields.
In addition to environmental pressure, low commodity prices and high production
costs are requiring citrus, vegetable and sugarcane growers to closely examine all
production inputs. Fertilizer inputs are typically 30 to 35% of non-labor farm costs
depending on commodity. Due to leaching of N from sandy soils, N uptake efficiency
in Florida is relatively low (i.e. 40 to 60%) depending on the type of fertilizer,
application rate, timing, and placement. Improving N uptake efficiency is also a
priority of state environmental regulators. Implementation of practices that keep
N in the crop root zone and improve N uptake efficiency would increase growers profits
through greater efficiency of fertilizer inputs.
Another environmental issue in Florida is P loading to surface waters. Reduction
in P loading has become an important goal of selected BMPs. As with N, any improvement
in P use efficiency would also benefit the growers financially and help protect
the environment by reducing the leaching and runoff of surplus fertilizer nutrients
to Florida's limited and environmentally vulnerable water resources. To reduce the
impact of fertilizer applications on the environment, fertilizer and irrigation
practices must be evaluated. Application rate and timing of soluble fertilizers,
controlled release fertilizers, and irrigation scheduling (provided by soil moisture
sensors and models) are technologies that growers must implement to adhere to BMPs
and/or improve overall soil nutrient management.
The presence of two bacterial diseases (i.e. canker and Huanglongbing, or greening),
has created an interest in higher performing citrus grove designs and cultural systems.
These improved citrus production systems are based on higher tree densities and
drip fertigation to promote greater growth in the early years after planting. Increased
tree planting density and size will improve early productivity and increase returns
to offset potential losses from these diseases. A system of intensive irrigation
and nutrient management (i.e. open hydroponics, a.k.a. Advanced Production Systems)
should accomplish these goals and allow complete grove replacement as a result of
tree loss from disease with time on a more profitable basis. Drip irrigation and
fertilizer injection is currently used by a small percentage of vegetable growers
and not used at all by sugarcane growers. Using drip fertigation practices similar
to those being developed for citrus will conserve water and can potentially improve
nutrient use efficiency compared with current seepage irrigation practices.
Weather and climate data are important for many management decisions that impact
water and nutrient efficiency. Data from the Florida Automated Weather Network (FAWN)
have been under-utilized due to the lack of integrated tools available to growers.
The number, reliability and accuracy of tools and models available to growers as
decision aids must be improved with time if greater strides in improving nutrient
and water use efficiency are to be made. These decision aids will have to be robust,
easily integrated into current management structures, and user friendly. Collection
of weather data and other information for these decision aids must be seamless to
the growers and nearly effortless.