Synthesis and performance of polyurethane coated urea as slow/controlled release fertilizer

Liu, Qingshan; Wu, Shu; Tie-jun, RU; Wang, Limin; Xing, Guangzhong; Wang, Jinming

doi:10.1007/s11595-012-0421-7

Cited by 45 publications

(19 citation statements)

References 11 publications

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“…The coating material types of CRF play a key role in gradually releasing the nutrient (Li et al, 2012), and the most important parameters for controlling nutrient release include the thickness of the coating membrane, followed by temperature, granule radius, soil microbial activity, etc. (Du et al, 2008;Kaplan et al, 2013), and they are controlled to match the nutrient requirement of the plants (Dai et al, 2008;Yan et al, 2008;Ni et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

Effects of a controlled-release fertilizer on yield, nutrient uptake, and fertilizer usage efficiency in early ripening rapeseed (Brassica napus L.)

Chen

Zhou

Liu

et al. 2016

J. Zhejiang Univ. Sci. B

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Background: Nitrogen (N), phosphorous (P), and potassium (K) are critical nutrient elements necessary for crop plant growth and development. However, excessive inputs will lead to inefficient usage and cause excessive nutrient losses in the field environment, and also adversely affect the soil, water and air quality, human health, and biodiversity. Methods: Field experiments were conducted to study the effects of controlled-release fertilizer (CRF) on seed yield, plant growth, nutrient uptake, and fertilizer usage efficiency for early ripening rapeseed (Xiangzayou 1613) in the red-yellow soil of southern China during 2011-2013. It was grown using a soluble fertilizer (SF) and the same amounts of CRF, such as SF1/CRF1 (3750 kg/hm 2 ), SF2/CRF2 (3000 kg/hm 2 ), SF3/CRF3 (2250 kg/hm 2 ), SF4/CRF4 (1500 kg/hm 2 ), SF5/CRF5 (750 kg/hm 2 ), and also using no fertilizer (CK). Results: CRF gave higher seed yields than SF in both seasons by 14.51%. CRF4 and SF3 in each group achieved maximum seed yield (2066.97 and 1844.50 kg/hm 2 , respectively), followed by CRF3 (1929.97 kg/hm 2 ) and SF4 (1839.40 kg/hm 2 ). There were no significant differences in seed yield among CK, SF1, and CRF1 (P>0.05). CRF4 had the highest profit (7126.4 CNY/hm 2 ) and showed an increase of 12.37% in seed yield, and it decreased by 11.01% in unit fertilizer rate compared with SF4. The branch number, pod number, and dry matter weight compared with SF increased significantly under the fertilization of CRF (P<0.05). The pod number per plant was the major contributor to seed yield. On the other hand, the N, P, and K uptakes increased at first and then decreased with increasing the fertilizer rate at maturity, and the N, P, and K usage efficiency decreased with increasing the fertilizer rate. The N, P, and K uptakes and usage efficiencies of the CRF were significantly higher than those of SF (P<0.05). The N accumulation and N usage efficiency of CRF increased by an average of 13.66% and 9.74 percentage points, respectively, compared to SF. In conclusion, CRF significantly promoted the growth of rapeseed with using total N as the base fertilizer, by providing sufficient N in the later growth stages, and last by reducing the residual N in the soil and increasing the N accumulation and N usage efficiency.

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Section: Introductionmentioning

confidence: 99%

Effects of a controlled-release fertilizer on yield, nutrient uptake, and fertilizer usage efficiency in early ripening rapeseed (Brassica napus L.)

Chen

Zhou

Liu

et al. 2016

J. Zhejiang Univ. Sci. B

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“…This approach has been used previously to compensate for defects that occurred during the preparation of polyurethane-coated pellets. 48 However, the addition of paraffin worsened the integrity of our coatings, producing more holes (Figure S4A), and the pellets also started to stick together within the pan coater, causing tearing. This likely occurred because of CH 2 Cl 2 becoming trapped within the paraffin wax matrix, reducing the rate of solvent evaporation (Figure S4B).…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

Development of Fertilizer Coatings from Polyglyoxylate–Polyester Blends Responsive to Root-Driven pH Change

Heuchan

Fan

Kowalski

et al. 2019

J. Agric. Food Chem.

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Many current controlled-release fertilizers (CRFs) are coated with nonbiodegradable polymers that can contribute to microplastic pollution. Here, coatings of self-immolative poly(ethyl glyoxylate) (PEtG) capped with a carbamate and blended with polycaprolactone (PCL) or poly(l-lactic acid) (PLA) were evaluated. They were designed to depolymerize and release fertilizers in the vicinity of plant roots, where the pH is lower than that in the surrounding environment. PEtG/PCL coatings exhibited significant temperature and pH effects, requiring 18 days at pH 5 and 30 °C, compared to 77 days at pH 7 and 22 °C, to reach 15% mass loss. Plant roots were also effective in triggering coating degradation. Spray-coating and melt-coating were explored, with the latter being more effective in providing pellets that retained urea prior to polymer degradation. Finally, PEtG/PCL-coated pellets promoted plant growth to a similar degree or better than currently available CRFs.

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“…To date, various materials have been utilized to develop SRF, which includes synthetic and natural polymers and inorganic materials. Although synthetic polymers have demonstrated promising results in terms of nutrient release longevity, the involvement of harmful solvent in the coating of synthetic polymers on urea and non-biodegradability leads to environmental and soil pollution [12][13][14][15]. On the other hand, natural polymers are suffering from their hydrophilic nature, which leads to the abrupt release of the nutrients at an unpredictable time [5].…”

Section: Introductionmentioning

confidence: 99%

A Degradable Inverse Vulcanized Copolymer as a Coating Material for Urea Produced under Optimized Conditions

et al. 2021

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Global enhancement of crop yield is achieved using chemical fertilizers; however, agro-economy is affected due to poor nutrient uptake efficacy (NUE), which also causes environmental pollution. Encapsulating urea granules with hydrophobic material can be one solution. Additionally, the inverse vulcanized copolymer obtained from vegetable oils are a new class of green sulfur-enriched polymer with good biodegradation and better sulfur oxidation potential, but they possess unreacted sulfur, which leads to void generations. In this study, inverse vulcanization reaction conditions to minimize the amount of unreacted sulfur through response surface methodology (RSM) is optimized. The copolymer obtained was then characterized using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). FTIR confirmed the formation of the copolymer, TGA demonstrated that copolymer is thermally stable up to 200 °C temperature, and DSC revealed the sulfur conversion of 82.2% (predicted conversion of 82.37%), which shows the goodness of the model developed to predict the sulfur conversion. To further maximize the sulfur conversion, 5 wt% diisopropenyl benzene (DIB) as a crosslinker is added during synthesis to produce terpolymer. The urea granule is then coated using terpolymer, and the nutrient release longevity of the coated urea is tested in distilled water, which revealed that only 65% of its total nutrient is released after 40 days of incubation. The soil burial of the terpolymer demonstrated its biodegradability, as 26% weight loss happens in 52 days of incubation. Thus, inverse vulcanized terpolymer as a coating material for urea demonstrated far better nutrient release longevity compared with other biopolymers with improved biodegradation; moreover, these copolymers also have potential to improve sulfur oxidation.

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Synthesis and performance of polyurethane coated urea as slow/controlled release fertilizer

Cited by 45 publications

References 11 publications

Effects of a controlled-release fertilizer on yield, nutrient uptake, and fertilizer usage efficiency in early ripening rapeseed (Brassica napus L.)

Effects of a controlled-release fertilizer on yield, nutrient uptake, and fertilizer usage efficiency in early ripening rapeseed (Brassica napus L.)

Development of Fertilizer Coatings from Polyglyoxylate–Polyester Blends Responsive to Root-Driven pH Change

A Degradable Inverse Vulcanized Copolymer as a Coating Material for Urea Produced under Optimized Conditions

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