Situated at the northern end of the historical Florida Everglades is the 280,000-ha tract of land called the Everglades Agricultural Area (EAA). This land was diked, canalized, and drained in the early 1900s to encourage the production of primarily sugarcane, vegetables, sod, and rice on its Histosols. The phosphorus in drainage water from the EAA is believed to be causing undesirable changes to the ecosystem in areas subject to legislated environmental protection. Phosphorus (P) load reduction “Best Management Practices” (BMPs) are being developed and implemented in the EAA to reduce agricultural production impacts on the wetland areas. The BMPs can be categorized as fertilizer, water management, or particulate control related, and can be applied effectively across the EAA. Ten farms, representative of the EAA soils, rainfall, crops, farm size, geographic location, and water management practices, were used in the study. The farms were monitored under pre-BMP conditions for 1 to 3 years. By Jan. 1995, seven of the 10 farms were operating under project-designed BMP packages that included only the fertilizer and water management options. Depending on the method used for adjusting for hydrologic variability between years, calculated P load reductions ranged from 25% to 60% between 1994 and 1995.
F.T. Izuno, R.W. Rice, and L.T. Capone
Eric H. Simonne and Monica Ozores-Hampton
With the development and implementation of best management practices (BMP), extension educators are facing a new and unexpected combination of challenges and opportunities. Because the BMP mandate requires a combination of research, demonstration, and outreach, it may affirm the relevance of the land grant mission in the 21st century, engage universities in interagency alliances, and help rediscover the wonders of the proven extension method. The extension approach to water and nutrient management needs to shift from “pollute less by applying less fertilizer” to “pollute less by better managing water.” Applied research is leading to advances in areas such as nutrient cycles and controlled-release fertilizers. At the same time, universities need to walk a fine line between education and regulation, address perennial issues of overfertilization, and consider the reformulation of recommendations that are now used in a quasi-regulatory environment. A combination of education, consensus, and novel approaches is needed to adapt the rigor of research to a multitude of growing conditions and risks of nutrient discharge in order to comply with U.S. federal laws and restore water quality.
Carolyn J. DeMoranville
In Massachusetts, cranberry (Vaccinium macrocarpon) bogs were historically developed in existing wetlands and new plantings are now established in mineral soils that are converted into constructed wetlands. To streamline the interaction between cranberry farming and wetlands protection, the state has defined “normal agricultural practices” that are exempt from wetlands regulations under certain circumstances. As part of that process and to qualify for the exemption, farmers are required to have a conservation farm plan and demonstrate the use of best management practices (BMPs) on their farms. The University of Massachusetts Amherst Cranberry Experiment Station (UMass Cranberry Station) was engaged to bring together the U.S. Department of Agriculture, Natural Resource Conservation Service (NRCS) and cranberry industry representatives to define BMPs specific to cranberry farming practices. Initially, the documents were reviewed by scientists and regulators for soundness of science and rigor of environmental protection. A grower committee reviewed the proposed BMPs to determine if the BMPs could be implemented on real farms. The next stage of the project consisted of defining areas where more research was needed to formulate good BMPs. In particular, research projects were initiated to study nitrogen and phosphorus nutrition. This research has become the basis for nutrition BMPs, national cranberry nutrition guidelines, and standards used by NRCS for cranberry nutrient management plans. The cranberry BMP project has continued with a regular cycle of revision and additions based on grower-identified needs for horticultural and environmental guidance. This connection to the growers, along with the regulatory link, accounts for the widespread adoption of BMPs in the cranberry industry. Local NRCS estimates that 75% to 80% of Massachusetts cranberry growers have current conservation farm plans that include BMP implementation.
Donald J. Merhaut, Lea Corkidi, Maren Mochizuki, Toan Khuong, Julie Newman, Ben Faber, Oleg Daugovish, and Sonya Webb
, organochlorine, and organophosphorus pesticides) across the second-tier priority areas ( Table 1 ). Table 1. Percentage of acreage within the Calleguas Creek and Santa Clara watersheds where best management practices (BMPs) were implemented to mitigate benchmark
Eric H. Simonne and Chad M. Hutchinson
Best management practices (BMPs) for vegetable crops are under development nationwide and in Florida. One goal of the Florida BMP program is to minimize the possible movement of nitrate-nitrogen from potato (Solanum tuberosum) production to surface water in the St. Johns River watershed without negatively impacting potato yields or quality. Current fertilizer BMPs developed for the area focus on fertilizer rate. Controlled-release fertilizers (CRF) have long been a part of nutrient management in greenhouse and nursery crops. However, CRFs have been seldom used in field-vegetable production because of their cost and release characteristics. Nutrient release curves for CRFs are not available for the soil moisture and temperature conditions prevailing in the seepage-irrigated soils of northern Florida. Controlled-leaching studies (pot-in-pot) in 2000 and 2001 have shown that plant-available nitrogen (N) was significantly higher early in the season from ammonium nitrate, calcium nitrate and urea compared to selected CRFs. However, N release from off-the-shelf and experimental CRFs was too slow, resulting in N recoveries ranging from 13% to 51%. Cost increase due to the use of CRFs for potato production ranged from $71.66 to $158.14/ha ($29 to $64 per acre) based on cost of material and N application rate. This higher cost may be offset by reduced application cost and cost-share pro-grams. Adoption of CRF programs by the potato (and vegetable) industry in Florida will depend on the accuracy and predictability of N release, state agencies' commitment to cost-share programs, and CRFs manufacturers' marketing strategies. All interested parties would benefit in the development of BMPs for CRFs.
Jeffrey G. Williamson and Jonathan H. Crane
recently surveyed indicated they would implement best management practices (BMPs) under the Florida Department of Environmental Protection presumption of compliance incentive ( Migliaccio et al., 2006 ). However, 66% reported that they would not spend more
John C. Majsztrik and John D. Lea-Cox
Restoration efforts in the Chesapeake Bay recently intensified with the 2010 introduction of federal total maximum daily load (TMDL) limits for all 92 bay watershed segments. These regulations have specific, binding consequences if any of the six states or the District of Columbia fail to meet interim goals, including loss of federal dollars for various programs and increasing regulation of point sources, if non-point source (agricultural and urban) nutrient reduction goals are not met in the watershed. As part of the effort to better understand and account for non-point sources of pollution in the watershed, a team of agricultural experts from across the bay region was recently assembled, including the nursery industry. The goal of this panel was to inform stakeholders and policymakers about the inputs and management practices used across all Bay states. To increase both the precision and accuracy of loading rate estimates, more precise information should guide future iterations of the Chesapeake Bay model. A more accurate accounting of land area by operation type (e.g., greenhouse, container, and field) is a primary issue for the nursery and greenhouse industry, because the current Chesapeake Bay model relies on USDA agricultural census data, which does not separate container and field production, which have very different nutrient and irrigation practices. Field operations also typically account for a higher percentage of production area in each state, which may skew model results. This is very important because the type of operation (field, container-nursery, or greenhouse operation) has a significant impact on plant density, types of fertilizer used, and application rates, which combine with irrigation and water management practices to affect potential nutrient runoff. It is also important to represent a variety of implemented best management practices (BMPs) in the Chesapeake Bay model such as vegetated buffer strips, sediment ponds, controlled-release fertilizer, and accurately assess how these mitigate both nutrient and sediment runoff from individual operations. There may also be opportunities for growers who have implemented BMPs such as low-phosphorus slow-release fertilizers (SRF), precision irrigation, etc., to gain additional revenue through nutrient trading. Although there are currently some questions about how nutrient trading will work, this could provide additional incentives for further implementation of BMPs by both ornamental and other agricultural growers. It is possible that the TMDL process currently being implemented throughout the Chesapeake Bay will be used as a remediation process for other impaired estuarine water bodies, which have similar water-use regulations and issues. The lessons learned about the Chesapeake Bay model in general, and for the nursery and greenhouse industry in particular, will likely provide guidance for how we can be proactive in reducing environmental impacts and protect the economic viability of ornamental growers in the future.
Forrest T. Izuno, R.W. Rice, and L.T. Capone
F. Iriarte, J. Fry, and N. Tisserat
Bermudagrass turf quality is commonly reduced in the transition zone by Ophiosphaerella herpotricha, a root-infecting fungus that causes spring dead spot (SDS). Fungicides applied in autumn typically result in poor to moderate disease suppression. Earlier research has indicated that some cultural practices, including core aerification or fertilization with soil acidifying nitrogen fertilizers, may suppress SDS. Our objective was to evaluate several treatment combinations for reducing disease severity. Treatments were arranged in a split-plot design, with whole plots being aerification + verticutting, or no cultivation. Subplots within whole plots consisted of a factorial arrangement of azoxystrobin (one September application of at 0.6 kg·ha-1), trinexapac-ethyl (three summer applications at 6.1 kg·ha-1), and ammonium sulfate (three summer applications with N at 49 kg·ha-1). After 1 year of treatment, spring turf quality was improved in all treatments that included trinexapac-ethyl. Diseased area was reduced from 34% to 21% in plots receiving azoxystrobin + trinexapac-ethyl.
Eric Simonne, David Studstill, Robert Hochmuth, Justin Jones, and Cynthia Stewart
The Federal Clear Water Act and Florida legislation have mandated the clean-up of impaired water bodies. The BMP manual for vegetable crops lists the cultural practices that could maintain productivity while minimizing environmental impact. BMPs focus on increased fertilizer and irrigation efficiency, but growers must be involved in the demonstration and adoption process if this voluntary program is to be successful. Three commercial vegetable fields from farms recognized as leaders in fertilizer and irrigation management were selected to demonstrate how irrigation and fertilizer management are linked together and how management may prevent water movement below the root zone of melons grown with plasticulture. In Spring 2004, dye (Brilliant blue FCF) was injected into the irrigation water three times during the growing season and soil profiles were dug to determine the depth of dye movement. Similar results were found at all three locations as the dye moved below at an average rate of 1.9 to 3.6 cm per day. Water movement was greater early in the season as irrigation was applied for transplant establishment. These results suggest that some leaching is likely to occur on light-textured soils, even when sophisticated irrigation and fertilization practices are followed. Based on these observations, cooperators spontaneously proposed to use two drip tapes, reduce preplant fertilizer, use a 100% injected N/K program, and/or add organic matter to the soil as attempts to slow water movement below the root zone of their crops. This project shows that growers are more likely to try and adopt sustainable practices when they actively participate in the educational process than when production changes are mandated through legislation.