scholarly journals Controlled-Release Fertilizers for Florida Citrus Production

EDIS ◽  
1969 ◽  
Vol 2004 (2) ◽  
Author(s):  
Tom Obreza ◽  
Bob Rouse

In the new age of Florida citrus production, Best Management Practices to protect water quality are being considered across the state. Growers have been encouraged to carefully consider nitrogen (N) fertilizer rates, application schedules, and irrigation management in their groves. Nitrogen sources have received little attention because most managers are accustomed to using water-soluble fertilizers like ammonium nitrate, ammonium sulfate, and urea. Synthetic controlled-release fertilizers (CRFs) have existed commercially for more than 35 years, but other than use in young-tree fertilizer blends, Florida citrus growers have avoided them due to high cost and lack of production experience. This document is SL-214, a fact sheet of the Soil and Water Science Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Published: January 2004. https://edis.ifas.ufl.edu/ss433

EDIS ◽  
2006 ◽  
Vol 2006 (14) ◽  
Author(s):  
Thomas A. Obreza ◽  
Robert Rouse ◽  
Edward A. Hanlon

SL-243, an 11-page fact sheet by T.A. Obreza, R. Rouse, and E.A. Hanlon, advises crop advisers, fertilizer dealers, citrus producers and other parties interested in citrus fertilization practices about the advances in fertilizer technology in the past ten years. Published by the UF Soil and Water Sciences Department, July 2006.


2010 ◽  
Vol 20 (1) ◽  
pp. 67-73 ◽  
Author(s):  
Thomas A. Obreza ◽  
Arnold Schumann

Florida citrus (Citrus spp.) producers must improve water and nutrient use efficiency to remain sustainable as they face increasing urbanization, plant disease, and environmental awareness. Producers have traditionally used water-soluble nitrogen (N) and phosphorus fertilizer sources with calendar-based irrigation, but they are slowly integrating enhanced efficiency fertilizers into nutrient management plans and converting to sensor or evapotranspiration-based irrigation scheduling. Recent research has improved the understanding of the citrus grove N budget, which has led to development of appropriate best management practices (BMPs) that will maintain production while protecting the environment. BMPs that have been shown to decrease N loss to groundwater include applying the appropriate fertilizer rate, splitting fertilizer applications, converting to fertigation, and improving irrigation scheduling.


2005 ◽  
Vol 15 (1) ◽  
pp. 36-46 ◽  
Author(s):  
Eric H. Simonne ◽  
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.


1993 ◽  
Vol 11 (4) ◽  
pp. 206-208
Author(s):  
T. Yeager ◽  
R. Wright ◽  
D. Fare ◽  
C. Gilliam ◽  
J. Johnson ◽  
...  

Abstract Container nursery bed runoff, reservoirs or ponds that contained runoff, wells, and surface water discharged from the property or at the property border were sampled at approximately 6-week intervals during April–October 1990 in Alabama, Florida, New Jersey, North Carolina, Ohio, and Virginia. Runoff from container beds averaged 8 and 20 ppm NO3-N, respectively, for nurseries using controlled-release fertilizers (CRF) and controlled-release fertilizers supplemented with solution fertilizers (CRFSS). Average NO3-N levels for runoff collection ponds, property borders, and wells were each less than 10 ppm, the drinking water limit, regardless of fertilizers used. However, ppm NO3-N for some samples exceeded the drinking water standard. In general, these data indicate reason for concern and nursery operators need to implement best management practices.


EDIS ◽  
2021 ◽  
Author(s):  
Lauren Marie Diepenbrock ◽  
Davie M. Kadyampakeni ◽  
Larry W. Duncan

Reviewed March 2021. There are no changes in recommendation from 2020.


2019 ◽  
Vol 37 (4) ◽  
pp. 113-119
Author(s):  
Kayla R. Sanders ◽  
Jeffrey S. Beasley ◽  
Edward W. Bush ◽  
Stacia L. Conger

Abstract Nutrient leaching during nursery container production can have negative effects on plant growth and the environment. The objective of this study was to evaluate effects of fertilizer source at two irrigation depths on nutrient leaching during coleus [Plectranthus scutellarioides (L.) Codd] ‘Solar Sunrise' container production to develop best management practices. Coleus received no fertilizer, a controlled-release fertilizer (CRF), or a water-soluble fertilizer (WSF) applied at 0.30 kg N and P per m3 (0.02 lb per ft3) and were irrigated at 1.9 or 3.8 cm.day−1 (0.7 or 1.5 in.day−1) for 56 days after planting (DAP). Leachate was analyzed every 7 DAP for inorganic N and dissolved total P (DTP). At 56 DAP, root biomass, leaf quality, and plant growth index were similar between CRF and WSF treatments at both irrigation depths. Highest inorganic N and DTP losses occurred within 21 DAP. Application of WSF resulted in higher cumulative N and DTP losses compared to CRF applications. Coleus irrigated at 3.8 cm.day−1 and fertilized with WSF resulted in higher DTP losses compared to CRF applications regardless of irrigation depth. Reducing irrigation reduced inorganic N leaching for each fertilizer source. Application of CRF provided consistent growth while curbing nutrient losses across both irrigation depths compared to WSF. Index words: controlled-release fertilizer, water-soluble fertilizer, nursery producers, best management practices. Chemicals used in this study: Micronutrients mix (Micromax®); controlled-release fertilizer (Osmocote® Classic); water-soluble fertilizer (Grower's Special). Species used in this study: Coleus [Plectranthus scutellarioides (L.) Codd] ‘Solar Sunrise'.


HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 498c-498
Author(s):  
A. Fares ◽  
A.K. Alva ◽  
S. Paramasivam

Water and nitrogen (N) are important inputs for most crop production. The main objectives of nitrogen best management practices (NBMP) are to improve N and water management to maximize the uptake efficiency and minimize the leaching losses. This require a complete understanding of fate of N and water mass balance within and below the root zone of the crop in question. The fate of nitrogen applied for citrus production in sandy soils (>95% sand) was simulated using a mathematical model LEACHM (Leaching Estimation And Chemistry Model). Nitrogen removal in harvested fruits and storage in the tree accounted the major portion of the applied N. Nitrogen volatilization mainly as ammonia and N leaching below the root zone were the next two major components of the N mass balance. A proper irrigation scheduling based on continuous monitoring of the soil water content in the rooting was used as a part of the NBMP. More than 50% of the total annual leached water below the root zone was predicted to occur in the the rainy season. Since this would contribute to nitrate leaching, it is recomended to avoid N application during the rainy season.


2003 ◽  
Vol 48 (7) ◽  
pp. 191-196 ◽  
Author(s):  
P.J. Goyne ◽  
G.T. McIntyre

The Cotton and Grains Adoption Program of the Queensland Rural Water Use Efficiency Initiative is targeting five major irrigation regions in the state with the objective to develop better irrigation water use efficiency (WUE) through the adoption of best management practices in irrigation. The major beneficiaries of the program will be industries, irrigators and local communities. The benefits will flow via two avenues: increased production and profit resulting from improved WUE and improved environmental health as a consequence of greatly reduced runoff of irrigation tailwater into rivers and streams. This in turn will reduce the risk of nutrient and pesticide contamination of waterways. As a side effect, the work is likely to contribute to an improved public image of the cotton and grain industries. In each of the five regions, WUE officers have established grower groups to assist in providing local input into the specific objectives of extension and demonstration activities. The groups also assist in developing growersÕ perceptions of ownership of the work. Activities are based around four on-farm demonstration sites in each region where irrigation management techniques and hardware are showcased. A key theme of the program is monitoring water use. This is applied both to on-farm storage and distribution as well as to application methods and in-field management. This paper describes the project, its activities and successes.


1994 ◽  
Vol 12 (4) ◽  
pp. 181-186
Author(s):  
Melinda C. Shiflett ◽  
Alex X. Niemiera ◽  
Carol E. Leda

Abstract The objective of this study was to determine how a mid-season CRF (controlled release fertilizer) reapplication to container-grown Ilex crenata ‘Helleri’ Thunb. affected growth, substrate solution N content, and the amount on N leached compared to a single early season CRF application (control). ‘Helleri’ holly liners were initially fertilized (March 7) with an 8 to 9 month CRF, Osmocote 18N-2.6P-9.9K (18-6-12), or a 12 to 14 month CRF, Osmocote 17N-3.1P-9.9K (17-7-12). A subset of plants received a CRF reapplication (half rate) of the respective Osmocote formulation on July 19, August 2, or August 16. In addition, 12 plants received a water soluble fertilizer solution (WSF) with each irrigation starting on July 19. All effluent was collected and analyzed for N. Substrate solution N and electrical conductivity (EC) levels (via the pour-through method) and foliar N concentrations were determined every two weeks. Throughout the experiment, plants were irrigated with an irrigation amount that resulted in an ≈ 0.25 leaching fraction (LF). Plant width was determined on November 1. Plant width values were higher for the first and second reapplication and WSF treatments for both formulations than the control. However, in terms of commercial size grades, plants of all treatments were in the same grade. Thus, there was no economic advantage to reapplying CRF. We concluded that CRF reapplication was not necessary when substrate solution N and foliar N values were ≥ 20 mg N/liter and ≥ 2.3%, respectively. Irrigating at a LF of 0.2, the mid-season CRF application increased the amount of N lost from containers by 42% compared to a single, early season CRF application.


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