Evaluation of a Soil Incubation Method to Characterize Nitrogen Release Patterns of Slow- and Controlled-Release Fertilizers

Abstract Several technologies have been proposed to characterize the nutrient release patterns of slow- release fertilizers (SRF) and controlled-release fertilizers (CRF) during the last few decades. These technologies have been developed mainly by manufacturers, and are product-specific, based on the regulation and analysis of each SRF and CRF product. Despite previous efforts to characterize SRF and CRF materials, no standardized, validated method exists to assess their nutrient release patterns. However, the increased production and distribution of these materials in specialty and nonspecialty markets requires an appropriate method to verify product claims and material performance. A soil incubation column leaching procedure was evaluated to determine its suitability as a standard method to estimate nitrogen (N) release patterns of SRFs and CRFs during 180 days. The influence of three soil/sand ratios, three incubation temperatures, and four soils on method behavior was assessed using five SRFs and three CRFs. In general, the highest soil/sand ratio increased the N release rate of all materials, but this effect was more marked for the SRFs. Temperature had the greatest influence on N release rates. For CRFs, the initial N release rates and the percentage N released/day increased as temperature increased. For SRFs, raising the temperature from 25 to 35°C increased initial N release rate and the total cumulative N released, and almost doubled the percentage released/day. The percentage N released/day from all products generally increased as the texture of the soil changed from sandy to loamy (Iowa>California>Pennsylvania>Florida). The soil incubation technique was demonstrated to be robust and reliable for characterizing N release patterns from SRFs and CRFs. The method was reproducible, and variations in soil/sand ratio, temperature, and soil had little effect on the results.

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Statistical Correlation of the Soil Incubation and the Accelerated Laboratory Extraction Methods to Estimate Nitrogen Release Rates of Slow- and Controlled-Release Fertilizers

Journal of AOAC International ◽

10.5740/jaoacint.13-004 ◽

2014 ◽

Vol 97 (3) ◽

pp. 677-686 ◽

Cited By ~ 3

Author(s):

L Carolina Medina ◽

Jerry B Sartain ◽

Thomas A Obreza ◽

Emily Leary ◽

William L Hall ◽

...

Keyword(s):

Controlled Release ◽

Extraction Method ◽

Nutrient Release ◽

Extraction Methods ◽

Statistical Correlation ◽

Official Method ◽

Soil Incubation ◽

N Release ◽

Production And Distribution ◽

Release Curve

Abstract Several technologies have been proposed to characterize the nutrient release patterns of enhanced-efficiency fertilizers (EEFs) during the last few decades. These technologies have been developed mainly by manufacturers and are product- specific based on the regulation and analysis of each EEF product. Despite previous efforts to characterize nutrient release of slow-release fertilizer (SRF) and controlled-release fertilizer (CRF) materials, no official method exists to assess their nutrient release patterns. However, the increased production and distribution of EEFs in specialty and nonspecialty markets requires an appropriate method to verify nutrient claims and material performance. Nonlinear regression was used to establish a correlation between the data generated from a 180-day soil incubation-column leaching procedure and 74 h accelerated lab extraction method, and to develop a model that can predict the 180-day nitrogen (N) release curve for a specific SRF and CRF product based on the data from the accelerated laboratory extraction method. Based on the R2 > 0.90 obtained for most materials, results indicated that the data generated from the 74 h accelerated lab extraction method could be used to predict N release from the selected materials during 180 days, including those fertilizers that require biological activity for N release.

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Optimization and Validation of an Accelerated Laboratory Extraction Method to Estimate Nitrogen Release Patterns of Slow- and Controlled-Release Fertilizers

Journal of AOAC International ◽

10.5740/jaoacint.12-482 ◽

2014 ◽

Vol 97 (3) ◽

pp. 661-676 ◽

Cited By ~ 3

Author(s):

L Carolina Medina ◽

Jerry B Sartain ◽

Thomas A Obreza ◽

William L Hall ◽

Nancy J Thiex

Keyword(s):

Controlled Release ◽

Extraction Method ◽

Nutrient Release ◽

Portion Size ◽

Effect Of Temperature ◽

Extraction Temperature ◽

Test Portion ◽

N Release ◽

Slow Release Fertilizers ◽

Controlled Release Fertilizers

Abstract Several technologies have been proposed to characterize the nutrient release and availability patterns of enhanced-efficiency fertilizers (EEFs), especially slow-release fertilizers (SRFs) and controlled-release fertilizers (CRFs) during the last few decades. These technologies have been developed mainly by manufacturers and are product-specific based on the regulation and analysis of each EEF product. Despite previous efforts to characterize EEF materials, no validated method exists to assess their nutrient release patterns. However, the increased use of EEFs in specialty and nonspecialty markets requires an appropriate method to verify nutrient claims and material performance. A series of experiments were conducted to evaluate the effect of temperature, fertilizer test portion size, and extraction time on the performance of a 74 h accelerated laboratory extraction method to measure SRF and CRF nutrient release profiles. Temperature was the only factor that influenced nutrient release rate, with a highly marked effect for phosphorus and to a lesser extent for nitrogen (N) and potassium. Based on the results, the optimal extraction temperature set was: Extraction No. 1—2:00 h at 25°C; Extraction No. 2—2:00 h at 50°C; Extraction No. 3—20:00 h at 55°C; and Extraction No. 4—50:00 h at 60°C. Ruggedness of the method was tested by evaluating the effect of small changes in seven selected factors on method behavior using a fractional multifactorial design. Overall, the method showed ruggedness for measuring N release rates of coated CRFs.

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Plant Growth and Leachate Electrical Conductivity and pH as Influenced by Controlled-release Fertilizer Blends and Coating Technologies

HortTechnology ◽

10.21273/horttech03767-17 ◽

2017 ◽

Vol 27 (5) ◽

pp. 639-643 ◽

Cited By ~ 1

Author(s):

Carey Grable ◽

Joshua Knight ◽

Dewayne L. Ingram

Keyword(s):

Trace Elements ◽

Controlled Release ◽

Polymer Coating ◽

Ornamental Plants ◽

Nutrient Release ◽

Dry Weight ◽

Polymer Coatings ◽

Release Rates ◽

Shoot Dry Weight ◽

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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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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Nitrogen Release Characteristics of a Bag Controlled Release Fertilizer

Research in Ecology ◽

10.30564/re.v2i1.1205 ◽

2019 ◽

Vol 2 (1) ◽

Author(s):

Yi Zhong ◽

Renyi Gui ◽

Zhuangzhuang Qian ◽

Shunyao Zhuang

Keyword(s):

Controlled Release ◽

Evaluation Method ◽

Ammonia Volatilization ◽

Slow Release ◽

Ammonia Emission ◽

N Leaching ◽

Nitrogen Release ◽

N Release ◽

Slow Release Fertilizers ◽

Controlled Release Fertilizers

Slow release fertilizers are designed to enhance crop yield and minimizing the loss of nitrogen (N) to environment. However, N release in leaching and loss in ammonia emission from bag controlled release fertilizers have not been previously evaluated under the standardized conditions in soil. Accordingly, a laboratory study was conducted to evaluate the characteristics of N release from a bag controlled fertilizer with 1, 3, 5 and 7 rows of hole (B-1, B-3, B-5, B-7) and a kraft bag without hole (B-W). The results showed that the amount of N leaching of B-1, B-3, B-5, B-7 and B-W were significantly lower than urea fertilizer without bag (U). The maximum N release from the fertilizers followed the order: U (83.16%) > B-7 (54.61%) > B-5 (54.02%) > B-W (51.51%) > B-3 (48.87%) > B-1 (38.60%) during the experimentation. Compared with U treatment, ammonia volatilization losses were significantly decreased by B-1, B-3, B-5, B-7 and B-W treatments. Based on N release and loss, a suitable bag with holes should be considered in practice when using the bag controlled fertilizer to meet an environment good objective. The evaluation method merits further study combined with field experiment.

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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 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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