A Rapid Technique for Prediction of Nutrient Release from Polymer Coated Controlled Release Fertilizers

Although controlled-release fertilizers (CRFs) have been used in container-grown ornamental plants for decades, new coating technologies and blends of fertilizers coated for specific release rates are being employed to customize fertility for specific environments and crops. A study was conducted in the transitional climate of Kentucky to determine the nutrient release rates of three controlled-release blends of 8- to 9-month release and growth response of ‘Double Play Pink’ japanese spirea (Spiraea japonica) and ‘Smaragd’ arbovitae (Thuja occidentalis). Fertilizer 1 (16N–3.5P–8.3K–1.8Mg + trace elements) and Fertilizer 2 (18N–3.1P–8.3K–1.8Mg + trace elements) were prototype blends with different experimental polymer coatings. Fertilizer 3 was a blend of 18N–2.2P–6.6K–1.1Ca–1.4Mg–5.8S + trace elements, which combined 100% resin-coated prills with a polymer coating. Fertilizer 4 was commercially available 15N–3.9P–10K–1.3Mg–6S + trace elements. Fertilizer 3 released its nutrients earlier in the 12-week study than the other three fertilizers and resulted in lower shoot dry weight in both species. The new polymer coating technologies show promise for delivering a predicted release rate and are appropriate for container production of these woody shrubs in Kentucky. An interesting side note of this experiment was that leachate pH measurements across treatments averaged 1.2 units lower for arbovitae (6.3) than for japanese spirea (7.5) at week 12. It was assumed that chemical and/or biological reactions at the root/substrate interface in arbovitae moderated pH increases over the study.

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Nitrogen Release Properties of Controlled-release Fertilizers during Tomato Production

HortScience ◽

10.21273/hortsci.49.12.1568 ◽

2014 ◽

Vol 49 (12) ◽

pp. 1568-1574 ◽

Cited By ~ 2

Author(s):

Luther C. Carson ◽

Monica Ozores-Hampton ◽

Kelly T. Morgan ◽

Jerry B. Sartain

Keyword(s):

Controlled Release ◽

Nonlinear Regression ◽

Nutrient Release ◽

Nitrogen Release ◽

Data Logger ◽

Tomato Crop ◽

Tomato Production ◽

N Release ◽

Soil Temperatures ◽

Controlled Release Fertilizers

Determination of nutrient release duration from controlled-release fertilizers (CRFs) or soluble fertilizers encapsulated in polymer, resin, or sulfur covered fertilizer coated with a polymer differs among manufacturers, but may be determined as 75% to 80% nitrogen (N) release at a constant temperature (e.g., 20 to 25 °C). Increases or decreases in temperature compared with the manufacturer release determination temperature increase or decrease CRF N release; thus, coated fertilizer may release more rapidly than stated during the fall season when soil temperatures in seepage-irrigated tomato (Solanum lycopersicum) production can reach 40.1 °C. The objectives of this study were to evaluate N release duration of CRFs by measuring N release from CRFs incubated in pouches under polyethylene mulch-covered raised beds and to determine the CRF duration suitable for incorporation into a fall tomato fertility program. In 2011 and 2013, 12 and 14 CRFs from Agrium Advanced Technologies, Everris, Florikan, and Chisso-Asahi Fertilizer were sealed in fiberglass mesh pouches (12.7 × 14 cm) that were buried 10 cm below the bed surface in a tomato crop grown using commercial production practices. A data logger collected soil temperature 10 cm below the bed surface. Pouches were collected and N content was measured eight times through two fall seasons. A nonlinear regression model was fit to the data to determine N release rate. During the 2011 and 2013 seasons, minimum, average, and maximum soil temperatures were 21.2 and 19.2, 25.7 and 23.5, and 32.2 and 27.7 °C, respectively. Seasonal total CRF N release was between 77.6% and 93.8% during 2011 and 58.3% and 94.3% in 2013. In 2011, PCU90 and in 2013, PCU90 and PCNPK120 had the highest seasonal total percentage N release (PNR) and FL180 had the lowest in both years. A nonlinear regression fit N release from CRF with R2 = 0.85 to 0.99 during 2011 and 0.49 to 0.99 during 2013. Nitrogen release from all CRFs was faster than the manufacturer’s stated release, probably as a result of high fall bed temperatures. A CRF or CRF mixture containing CRFs of 120- to 180-day release duration may be recommended, but the CRFs must release greater than 75% N during the season.

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372 Nitrogen and Phosphorus Release from Controlled-release Fertilizers while Overwintering Nursery Stock under Plastic

HortScience ◽

10.21273/hortsci.35.3.456d ◽

2000 ◽

Vol 35 (3) ◽

pp. 456D-456

Author(s):

Andrew Ristvey ◽

John Lea-Cox

Keyword(s):

Controlled Release ◽

Variable Temperature ◽

Nutrient Release ◽

Phosphorus Release ◽

Early Spring ◽

Late Winter ◽

Nitrogen And Phosphorus ◽

Major Loss ◽

Few Data ◽

Controlled Release Fertilizers

Nutrient release patterns from several different controlled-release fertilizers (CRF) were studied during the overwintering period of a long-term nutrient uptake, leaching, and loss study of Azalea (Rhododendron) cv. `Karen' and Holly (Ilex cornuta) cv. `China Girl', under sprinkler and drip irrigation. In Maryland, diurnal winter temperatures can vary from ≈10 °C to above 15 °C. Most growers, therefore, cover frames with opaque plastic for cold protection from November through April. This is also the period when many growers apply CRFs on those plant species that take more than 1 year to produce. Few data are presently available on the release patterns of CRFs under variable temperature conditions in late winter/early spring. We hypothesized that substrate temperatures warmer than 15–16 °C will result in CRFs releasing nutrients at a time when root systems are inactive, with a major loss of nutrients with the first few irrigations in Spring. This 105-day study quantified nitrogen (N) and phosphorus release patterns from four brands of CRF (Osmocote, Nutricote, Scotts High N, and Polyon) with 270- and 360-day release rates, under these conditions. Each CRF was top dressed onto blocks of 18-month-old holly or azalea (n = 112) in 11.5-L (3-gal) containers, at a (low) rate of 6.1 g N per container. Ten randomly selected pots from each treatment were sampled every 15 days using two sequential leachings of distilled water, for a target leaching fraction of 25%. Leachates were recovered and analyzed for nitrate and orthophosphate concentrations. Ambient canopy temperatures were recorded continuously with remote temperature (HoBo) sensors from which degree days above 15–16 °C were calculated and correlated with CRF release patterns.

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Nutrient Release from Controlled-release Fertilizers in Acid Substrate in a Greenhouse Environment: I. Leachate Electrical Conductivity, pH, and Nitrogen, Phosphorus, and Potassium Concentrations

HortScience ◽

10.21273/hortsci.41.3.780 ◽

2006 ◽

Vol 41 (3) ◽

pp. 780-787 ◽

Cited By ~ 22

Author(s):

Donald J. Merhaut ◽

Eugene K. Blythe ◽

Julie P. Newman ◽

Joseph P. Albano

Keyword(s):

Electrical Conductivity ◽

Controlled Release ◽

Nutrient Release ◽

Low Fertility ◽

Plant Production ◽

Production Cycle ◽

Permissible Levels ◽

Phosphorus And Potassium ◽

Acid Substrate ◽

Controlled Release Fertilizers

Release characteristics of four types of controlled-release fertilizers (Osmocote, Nutricote, Polyon, and Multicote) were studied during a 47-week simulated plant production cycle. The 2.4-L containers containing a low-fertility, acid-based substrate were placed in an unheated greenhouse and subjected to environmental conditions often used for production of azaleas and camellias. Leachate from containers was collected weekly and monitored for pH, electrical conductivity, and concentrations of NH4+ N, NO3–N, total P and total K. Leachate concentrations of all nutrients were relatively high during the first 10 to 20 weeks of the study, and then gradually decreased during the remaining portion of the experiment. Differences were observed among fertilizer types, with Multicote often resulting in higher concentrations of N, P, and K in leachates compared to the leachates from the other fertilizer types during the first half of the study. Concentrations of NO3– and P from all fertilizer types were often above permissible levels as cited in the federal Clean Water Act.

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Determination of Nitrogen, Phosphorus, and Potassium Release Rates of Slow- and Controlled-Release Fertilizers: Single-Laboratory Validation, First Action 2015.15

Journal of AOAC International ◽

10.5740/jaoacint.15-0294 ◽

2016 ◽

Vol 99 (2) ◽

pp. 353-359 ◽

Cited By ~ 3

Author(s):

Nancy Thiex

Keyword(s):

Controlled Release ◽

Nutrient Release ◽

Official Method ◽

Release Rates ◽

Expert Review ◽

Expert Review Panel ◽

Phosphorus And Potassium ◽

Single Laboratory ◽

Controlled Release Fertilizers

Abstract A previously validated method for the determination of nitrogen release patterns of slow- and controlled-release fertilizers (SRFs and CRFs, respectively) was submitted to the Expert Review Panel (ERP) for Fertilizers for consideration of First Action Official MethodSM status. The ERP evaluated the single-laboratory validation results and recommended the method for First Action Official Method status and provided recommendations for achieving Final Action. The 180 day soil incubation-column leaching technique was demonstrated to be a robust and reliable method for characterizing N release patterns from SRFs and CRFs. The method was reproducible, and the results were only slightly affected by variations in environmental factors such as microbial activity, soil moisture, temperature, and texture. The release of P and K were also studied, but at fewer replications than for N. Optimization experiments on the accelerated 74 h extraction method indicated that temperature was the only factor found to substantially influence nutrient-release rates from the materials studied, and an optimized extraction profile was established as follows: 2 h at 25°C, 2 h at 50°C, 20 h at 55°C, and 50 h at 60°C.

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A comprehensive review on biodegradable polymers and their blends used in controlled-release fertilizer processes

Reviews in Chemical Engineering ◽

10.1515/revce-2014-0021 ◽

2015 ◽

Vol 31 (1) ◽

Cited By ~ 50

Author(s):

Zahid Majeed ◽

Nur Kamila Ramli ◽

Nurlidia Mansor ◽

Zakaria Man

Keyword(s):

Controlled Release ◽

Biodegradable Polymers ◽

Crop Yields ◽

Nutrient Release ◽

Polymer Coatings ◽

Classification Criteria ◽

Methodological Issues ◽

Comprehensive Review ◽

Modeling Data ◽

Controlled Release Fertilizers

AbstractBiodegradable polymer-coated controlled-release fertilizers (PC-CRFs) are essential means to reduce cost, improve marketability, conserve land fertility, achieve high crop yields and combat climate challenges. It is known that about 15–30% of any fertilizer packed in a PC-CRF does not get released due to the concentration gradient difference across the polymer coatings. To release the trapped fertilizer(s), it is desired that polymer-based coatings should biodegrade after the fertilizer is completely released into the soil. This review has aimed to provide a comprehensive account for various biodegradable polymers/blends derived either from natural or synthetic sources which are cited in the literature for PC-CRFs. In addition, this review covers the discussion on their classification criteria, trends in the processes of fertilizer coatings, methodological issues for their biodegradation assessment, coating attributes that affect the biodegradability and an outlook into their biodegradation kinetic models that involve enzymes and microbial processes. It also concludes that experimental as well as modeling data are insufficient to assess the biodegradation contribution of the overall nutrient release in PC-CRFs.

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Mathematical modelling of controlled release fertilizer

Malaysian Journal of Fundamental and Applied Sciences ◽

10.11113/mjfas.v13n4-1.878 ◽

2017 ◽

Vol 13 (4-1) ◽

pp. 372-374

Author(s):

Sayed Ameenuddin Irfan ◽

Radzuan Razali

Keyword(s):

Controlled Release ◽

Release Rate ◽

Plant Uptake ◽

Molecular Diffusion ◽

Finite Difference Methods ◽

Nutrient Release ◽

Ionic Diffusion ◽

Difference Methods ◽

Uptake Of Nutrients ◽

Controlled Release Fertilizers

Controlled release fertilizers (CRFs) are essential for sustainable agriculture system. CRFs are designed to maintain the constant optimum release rate of nutrients from the coated granule. This increase the plant uptake of nutrients hence reduces the soil pollution and decreases the crop expenditure. In the literature, the maximum studies have been done by considering the molecular diffusion as the only phenomenon responsible for nutrient release from CRFs. The molecular diffusion model is solved mostly by using the variable separable methods and Laplace transform as well as finite difference methods by different researchers. The release of NPK (nutrient) depends on both molecular diffusions which are expressed by Fick’s second law of diffusion and ionic diffusion, due to the electrolytic behavior of NPK in the soil. In this work, an analytical solution is presented. The obtained solution helps to find the effect of granule coating thickness, nutrient release rate, pH of the soil and temperature of the soil on the nutrient release profiles.

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Nutrient Release from Controlled-release Fertilizers in Acid Substrate in a Greenhouse Environment: II. Leachate Calcium, Magnesium, Iron, Manganese, Zinc, Copper, and Molybdenum Concentrations

HortScience ◽

10.21273/hortsci.41.3.788 ◽

2006 ◽

Vol 41 (3) ◽

pp. 788-793 ◽

Cited By ~ 1

Author(s):

Eugene K. Blythe ◽

Donald J. Merhaut ◽

Julie P. Newman ◽

Joseph P. Albano

Keyword(s):

Controlled Release ◽

Cultural Practices ◽

Nutrient Release ◽

Greenhouse Production ◽

Production Program ◽

Manganese Zinc ◽

Calcium Magnesium ◽

Iron Manganese ◽

Acid Substrate ◽

Controlled Release Fertilizers

Leachate from containerized substrate containing one of four different controlled-release fertilizers (Osmocote, Nutricote, Polyon, or Multicote) were monitored for concentrations of Ca, Mg, Fe, Mn, Zn, Cu, and Mo during a 47-week period. Environmental and cultural practices simulated an unheated greenhouse production program typically used for low-nutrient-requiring crops such as azalea and camellia. Leachate concentrations of all nutrients were relatively high during the first 10 to 20 weeks of the study, and then gradually decreased during the remaining portion of the experiment. Few differences were observed among fertilizer types. Of the elements monitored, only Fe and Mn leachate concentrations were above critical levels specified in the Clean Water Act by the U.S. EPA.

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Rapid and Low-Cost Method for Evaluation of Nutrient Release from Controlled-Release Fertilizers Using Electrical Conductivity

Journal of Polymers and the Environment ◽

10.1007/s10924-018-1309-1 ◽

2018 ◽

Vol 26 (12) ◽

pp. 4388-4395 ◽

Cited By ~ 2

Author(s):

Eduardo Lopes Cancellier ◽

Fien Degryse ◽

Douglas Ramos Guelfi Silva ◽

Rodrigo Coqui da Silva ◽

Mike John McLaughlin

Keyword(s):

Electrical Conductivity ◽

Controlled Release ◽

Low Cost ◽

Nutrient Release ◽

Controlled Release Fertilizers

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Nutrient Release Characteristics From Four Types of Controlled-release Fertilizers

HortScience ◽

10.21273/hortsci.39.4.797a ◽

2004 ◽

Vol 39 (4) ◽

pp. 797A-797

Author(s):

Donald J. Merhaut* ◽

Joseph Albano ◽

Eugene K. Blythe ◽

Julie Newman

Keyword(s):

Controlled Release ◽

Nutrient Release ◽

Forest Products ◽

Nutrient Content ◽

Experimental Period ◽

Release Rates ◽

Calcium Magnesium ◽

The Media ◽

Iron Manganese ◽

Controlled Release Fertilizers

Release patterns of ammonium, nitrate, phosphorus, potassium, calcium, magnesium, iron, manganese and zinc were measured during an eleven month period for four types of Controlled Release Fertilizers (CRF): Apex 17-5-11, Multicote 17-5-11, Nutricote 18-6-8 and Osmocote 24-4-9. Rate of fertilizer incorporation was 2.3 kg/m3 of nitrogen. Media consisted of 50% composted forest products, 35% ¼%-3/4% pine bark and 15% washed Builder's sand. The media was also amended with 0.60 kg/m3 of dolomite. Fertilizer was incorporated into the media with a cement mixer and placed into 2.6-L black polyethylene containers. Containers were placed on benches outside. Air and media temperature were monitored throughout the 11-month period. Containers were irrigated through a ring-dripper system. Leachate was collected twice weekly. Leachate electrical conductivity, pH, and nutrient content were measured weekly. Significant differences in the nutrient release patterns were observed between fertilizer types throughout much of the experimental period. Release rates were significantly greater during the first 20 weeks of the study compared to the last 20 weeks of the study, regardless of the fertilizer type.

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