Controlled release of nitrogen-source fertilizers by natural-oil-based poly(urethane) coatings: The kinetic aspects of urea release

Urea fertilizer is a major source of nitrogen, which is one of the essential nutrients for plant growth. Due to its uncontrollable release, this chemical can be wasted easily by leaching and volatilization that can adversely cause the contamination to the environment. In this work, a controlled-release material for urea fertilizer has been prepared by using degradable polylactic acid. Unlike other conventional controlled-release system, the resulting material is able to provide an efficient supply of urea fertilizer, without causing further contamination to the environment from residue material, as polylactic acid can be degraded in the environment. Micron-size particles of polylactic acid coated urea were prepared by employing atomizing technique. Effect of the preparation conditions; urea/PLA composition, PLA concentration, and pressure of atomizing gun on the particle size of material are investigated. The urea release rate of these samples is then studied by employing UV-Visible spectrophotometer. In addition, the effect of preparation conditions on shape and morphology of sample is determined by using Scanning Electron Microscope (SEM).

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Effect of Nitrogen Source and Timing on Highbush Blueberry Performance

HortScience ◽

10.21273/hortsci.27.12.1265 ◽

1992 ◽

Vol 27 (12) ◽

pp. 1265-1267 ◽

Cited By ~ 6

Author(s):

Eric J. Hanson ◽

Jorge B. Retamales

Keyword(s):

Controlled Release ◽

Dissolution Rate ◽

Nitrogen Source ◽

Vaccinium Corymbosum ◽

Nitrogen Fertilizers ◽

Highbush Blueberry ◽

Single Application ◽

Highbush Blueberries ◽

Controlled Release Fertilizers ◽

Leaf N

`Bluecrop' highbush blueberries (Vaccinium corymbosum L.) received various N fertilizer treatments for 5 years. Treatments were evaluated by measuring berry yields and leaf N levels annually and bush size after 5 years. Nitrogen fertilizers increased yields and leaf N levels compared with nonfertilized controls. Split applications of urea (half applied at budbreak, half at petal fall) resulted in 10% higher yields than the same amount in a single application at budbreak. Urea and two controlled-release fertilizers (CRF) with different dissolution rates (3 to 4 months, 8 to 9 months) resulted in similar yields and leaf N levels when compared at the same rate of N. The dissolution rate of the CRF materials did not affect yields or leaf N levels.

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Synthesis and Characterization of Controlled-Release Urea Fertilizer from Superabsorbent Hydrogels

Indonesian Journal of Chemistry ◽

10.22146/ijc.44230 ◽

2020 ◽

Vol 20 (3) ◽

pp. 616

Author(s):

Salih Muharam ◽

Afria Fitri ◽

Lela Mukmilah Yuningsih ◽

Yulia Mariana Tessa Ayudia Putri ◽

Isnaini Rahmawati

Keyword(s):

Controlled Release ◽

Ph Control ◽

Superabsorbent Hydrogel ◽

Urea Fertilizer ◽

Urea Release ◽

Controlled Release Urea ◽

Carboxy Methyl ◽

Controlled Release Fertilizers ◽

Superabsorbent Hydrogels

It is very important to develop controlled-release fertilizers to ensure efficiency and environmental protection. This study aims to make a superabsorbent hydrogel-based controlled-release urea fertilizer. Superabsorbent hydrogels were prepared from the cellulose of corn cobs cross-linking with epichlorohydrin, and then an amount of urea as a fertilizer was stored inside the hydrogels (GEL-A). The GEL-A functionalization with carboxy-methyl was also carried out in this study to improve the hydrophilicity of hydrogels (GEL-B). GEL-A and GEL-B were immersed in water at a certain pH and temperature range and the urea concentration released from the hydrogels was monitored by a spectrophotometer. The results showed that the urea released by GEL-A and GEL-B was not much different. Respectively, the urea efficiency of GEL-A and GEL-Bwas around 5.29% and 5.56% for 180 min. The urea released from both hydrogels was not significantly affected by changes in the temperature of the solution. Urea release was influenced by pH, and the rate of urea release of GEL-B was faster than GEL-A, so pH control was needed in the application of this slow-release fertilizer.

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Matriks Pengontrol Pelepasan Urea Berbasis Karagenan: Pengaruh Konsentrasi Glutaraldehid

Jurnal Teknik Kimia Indonesia ◽

10.5614/jtki.2019.18.1.3 ◽

2020 ◽

Vol 18 (1) ◽

pp. 17

Author(s):

Sperisa Distantina ◽

Mujtahid Kaavessina ◽

Fadilah Fadilah

Keyword(s):

Controlled Release ◽

Mathematic Model ◽

Urea Concentration ◽

Urea Solution ◽

Chemically Modified ◽

Urea Content ◽

Urea Release

Abstrak. Pada penelitian ini, matrik hidrogel berbasis karagenan dibuat dan diaplikasikan untuk mengontrol pelepasan urea. Tujuan penelitian ini adalah mempelajari pengaruh konsentrasi glutaraldehid terhadap kecepatan pelepasan urea dan menyusun model kecepatan pelepasan urea. Film karagenan dimodifikasi secara kimiawi menggunakan ikatan silang atau crosslinking dengan glutaraldehid. Larutan karagenan 7 g/100 mL dicetak menjadi lembaran dan kemudian dikeringkan sehingga diperoleh lapisan film. Film direndam dalam larutan glutaraldehid dengan konsentrasi tertentu selama 2 menit dan dilanjutkan dipanaskan pada suhu 110oC selama 20 menit. Film yang dihasilkan dicuci dengan etanol dan dikeringkan. Pengisian urea ke dalam matrik film menggunakan metode difusi. Film kering direndam dalam larutan urea 0,074 g/mL selama satu jam dan selanjutnya dikeringkan. Kecepatan pelepasan urea dari film ke dalam media air dievaluasi berdasarkan data konsentrasi urea dalam cairan sebagai fungsi waktu. Berdasarkan hasil penelitian didapatkan bahwa semakin besar konsentrasi glutaraldehid (1-5%) menyebabkan urea yang tersimpan di dalam film semakin rendah. Model matematika yang diusulkan dapat mewakili peristiwa pelepasan urea dari film. Film berbasis karagenan yang dihasilkan berpotensi sebagai matrik pengontrol pelepasan urea. Kata kunci: crosslinking, glutaraldehid, hidrogel, karagenan, urea. Abstract. Controlled Release Matrices of Urea from Carrageenan: Effect of Glutaraldehyde Concentration. In this study, carrageenan-based hydrogel matrices were prepared and applied for urea controlled release. The aim of this work was to study the effect of glutaraldehyde concentration on the rate of urea release in water. Carrageenan films were chemically modified by crosslinking with glutaraldehyde. The films were prepared by casting the aqueous carrageenan 7 g/100 mL and then followed by drying. The films obtained were immersed in certain glutaraldehyde concentration for 2 min and then heated in the oven at 110oC for 20 min. The crosslinked films were washed using ethanol and then air-dried until the weight is constant. The dried films were immersed in a urea solution (0.074g/ml) for 1 hr and then dried. The rate of urea release was determined by measuring the urea concentration in water as a function of time of release. Results showed that higher glutaraldehyde concentration (1–5%) produced films with less urea content. The proposed mathematic model of urea release from the film can represent the rate of urea release. The prepared carrageenan-based film has the potential for controlling of urea release. Keywords: carrageenan, crosslinking, glutaraldehyde, hydrogel, urea. Graphical Abstract

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1035 CONTAINER ORNAMENTAL PRODUCTION IN AN ARTIFICIAL POTTING MIX

HortScience ◽

10.21273/hortsci.29.5.576f ◽

1994 ◽

Vol 29 (5) ◽

pp. 576f-576

Author(s):

Fred D. Rauch ◽

Paul K. Murakami

Keyword(s):

Controlled Release ◽

Nitrogen Source ◽

Nitrogen Sources ◽

Ammonium Nitrogen ◽

Dolomitic Lime ◽

Foliage Plants ◽

Controlled Release Fertilizers

Several trials have been conducted to determine the optimum amendment level for the production of container foliage plants in a 1:1, V:V, peat:perlite potting mix. Experiments with various controlled-release fertilizers have shown superior growth and quality with resin coated products in an artificial mix. This appears to correspond to the nitrogen source with those containing nitrate and ammonium nitrogen giving better results than those with other nitrogen sources, such as IBDU or urea. Trials with variable rates of dolomitic lime resulted in better or equal growth and quality of a variety of foliage plants without added lime even at pH levels of 4.0. These results suggest the recommendations for the production of container plants in mixes without soil need to be reviewed and perhaps revised.

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Synthesis of Biodegradable Mixing-Polymer as Coating Material for Controlled-Release Urea Fertilizer

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1152.43 ◽

2019 ◽

Vol 1152 ◽

pp. 43-51 ◽

Cited By ~ 2

Author(s):

Huu Trung Nguyen ◽

Van Dat Doan ◽

Van Dung Trinh

Keyword(s):

Controlled Release ◽

Low Cost ◽

Coating Material ◽

Urea Fertilizer ◽

Bonding Structure ◽

Physico Chemical ◽

Coating Method ◽

Urea Release ◽

Kinetics Of ◽

Controlled Release Urea

The biodegradable mixing-polymer as low cost, environmentally friendly coating material for controlled-release urea fertilizer was synthesized by borax crosslinked phosphated distarch phosphate (PDSP)/polyvinyl alcohol (PVA) and polyacrylic acid (PAA) via pan coating method. The physico-chemical characteristics of biodegradable mixing-polymer were confirmed by FTIR, TGA and SEM techniques. The kinetics of urea release were also carefully investigated in water and soil. It’s been found that a uniform layer with better bonding structure was created on surface of the mixing-polymer PDSP/PVA-PAA and the time released 70% urea reached 6 hours in water and more than 27 days in soil.

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Effect of Temperature on the Behavior of Slow Release Fertilizer from ENR-50/RH/Urea Composites

Materials Science Forum ◽

10.4028/www.scientific.net/msf.1021.308 ◽

2021 ◽

Vol 1021 ◽

pp. 308-316

Author(s):

Marwa N Al-Samarrai ◽

Rosniza Hamzah

Keyword(s):

Controlled Release ◽

Slow Release ◽

Coating Material ◽

Effect Of Temperature ◽

The Third ◽

Slow Release Fertilizer ◽

Urea Release ◽

Uv Visible ◽

Release Method ◽

Fast Release

Generally, chemical fertilizer is considered as a one of the most significant materials for increasing food production. However, the fast release of the conventional fertilizer could effect negatively on the plants. Thus, the idea of using controlled release method in the agriculture application has emerged recently due to the efficiency of fertilizers can be improved by the controlled-release method. The objective of this work is to synthesize a new Slow Release Fertilizer from three different materials; the first one is urea, which is the conventional fertilizer, the second one is the rice husk (RH), which represents the carrier material, and the third one is epoxidized natural rubber (ENR-50), which represents the coating material. This work was divided into three series. The first series is the production of RH/Urea beads. RH was treated with alkaline NaOH at 1wt.% according to the weight of RH. The treated RH was then mixed with urea that produced treated RH/urea beads. In the second series, 200 mg of ENR-50 was applied to produce thicknes of coating material for treated RH/urea beads. In the third series, treated RH/urea beads coated with 200 mg of ENR-50 were subjected to the released behavior at different temperature in the water. After that, the prepared samples were characterized using Scanning Electron Microscopy (SEM) and UV-visible spectroscopy. Results suggested that the increasing of temperature has increased the rate of urea release of SRF samples in the water. Furthermore, the SRF sample at 35, 45, and 55 °C showed shorter time of release at 40, 34, and 17 day as compared to 47 day of SRF at room temperature.

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