New coating formulation for the slow release of urea using a mixture of gypsum and dolomitic limestone

Babadi, Farahnaz Eghbali; Yunus, Robiah; Rashid, Suraya Abdul; Salleh, Mohamad Amran Mohd; Ali, Sharafat

doi:10.1016/j.partic.2014.12.011

Cited by 51 publications

(15 citation statements)

References 15 publications

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“…Ammonium cations are adsorbed to negatively charge surfaces when wetland cells are flooded. Babadi et al reported that adsorption of nitrogen products is known to be stronger on soils with high cation-exchange capacity [21]. Moreover, accumulated organic materials in wetland form humic substances that have significant CEC [22].…”

Section: Resultsmentioning

confidence: 99%

Changes in Land Use and their Effects on Soil Properties in Huixian Karst Wetland System

Li¹,

Jin²,

Li³

2017

Pol. J. Environ. Stud.

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To gain a better understanding of the impact from the land-use change in the Huixian karst wetland system, we analyzed soil microflora, enzyme activities, and physicochemical properties from three land-use types (natural wetland, paddy field, and dry farmland). The results showed that soil pH, soil organic carbon, total nitrogen, cation exchange capacity, exchangeable Ca and Mg, and the cellulase and alkaline phosphatase activities in the dry farmland were significantly lower than those in the paddy field and natural wetland (p<0.05). However, soil pH, soil organic carbon, total nitrogen, cation exchange capacity, exchangeable Ca and Mg, and the cellulase and alkaline phosphatase activities made no significant difference to the paddy field and the natural wetland (p>0.05). Moreover, the soil microbial biomass carbon and nitrogen in the dry farmland were also lower than those in the paddy field and natural wetland, although no significant differences were observed (p>0.05). This suggests that, in the alkali condition, natural wetland with high biomass and weak microbial activity may be an important carbon sink. In the CCA biplot, it can be seen that the natural wetland cluster intersects with the paddy field cluster and the dry farmland cluster in the same quadrant (although the paddy field and the dry farmland clusters are separate). Therefore, we concluded that the natural wetland usually was reclaimed as paddy field or dry farmland directly for agricultural output in the Huixian karst wetland system. The paddy field has a waterlogged condition and shows the similar results to natural wetland, which can be regarded as artificial wetland. In view of the similar ecosystem services by paddy fields as substitutes of natural wetland, if the degradation trend of natural karst wetland can't be reversed, the paddy field should be preserved in the Huixian karst wetland system for its ecosystem service.

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Section: Resultsmentioning

confidence: 99%

Changes in Land Use and their Effects on Soil Properties in Huixian Karst Wetland System

Li¹,

Jin²,

Li³

2017

Pol. J. Environ. Stud.

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“…The crushing test of prepared samples was carried out to ensure stability of granules against impact during the synthesis phase until their packaging and transportation. Urea granules start to break and turn into fine powder due to their delicate nature [55]. This powdered urea has no further usage for agricultural purposes.…”

Section: Crushing Strengthmentioning

confidence: 99%

“…The amount of stress where the granules cracked was noted. This value is known as a crushing strength [55].…”

Section: Crushing Strengthmentioning

confidence: 99%

Biodegradable Polymer Coated Granular Urea Slows Down N Release Kinetics and Improves Spinach Productivity

et al. 2020

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Low nitrogen (N) utilization efficiency due to environmental N losses from fertilizers results in high-cost on-farm production. Urea coating with biodegradable polymers can prevent these losses by controlling the N release of fertilizers. We calculated N release kinetics of coated granular with various biodegradable polymeric materials and its impact on spinach yield and N uptake. Different formulations were used, (i) G-1: 10% starch + 5% polyvinyl alcohol (PVA) + 5% molasses; (ii) G-2: 10% starch + 5% PVA + 5% paraffin wax (PW); (iii) G-3: 5% gelatin + 10% gum arabic + 5% PW; (iv) G-4: 5% molasses + 5% gelatin + 10% gum arabic, to coat urea using a fluidized bed coater. The morphological and X-ray diffraction (XRD) analyses indicated that a uniform coating layer with no new phase formation occurred. In the G-2 treatment, maximum crushing strength (72.9 N) was achieved with a slowed-down N release rate and increased efficiency of 31%. This resulted in increased spinach dry foliage yield (47%), N uptake (60%) and apparent N recovery (ANR: 130%) from G-2 compared to uncoated urea (G-0). Therefore, coating granular urea with biodegradable polymers is a good choice to slower down the N release rate and enhances the crop yield and N utilization efficiency from urea.

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“…The coating process employed in this work has been adopted from our previous work on gypsum-dolomite coated urea [32]. A stainless steel rotary pan (R-1, 60 cm in diameter and 12 cm in pan height) ( Figure 2) was used to coat the urea particles.…”

Section: Coating Processmentioning

confidence: 99%

Response Surface Method in the Optimization of a Rotary Pan-Equipped process for Increased Efficiency of Slow-Release Coated Urea

et al. 2019

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The high solubility of urea in water and its consequent leaching into the soil adversely prevents its full assimilation by plants. An improved slow-release process could effectively minimise the loss of fertilizer material and thus mitigate the associated environmental pollution. In this study, the effects of the operational variables on the efficiency of the urea coating process in a rotary pan have been systematically analysed. A mixture of gypsum-sulphur was used as the coating material with refined water as a binder. In order to comprehensively investigate the impact of each process variable on the efficiency and any potential interactions between them, the effects of particle size, coating material percentage, rotational speed of the pan, spray flow rate and the amount of sprayed water were investigated and analysed via a central composite design of experiments (DoE). The second-order polynomial model provided the best correlation for the experimental data. The predictive model was then used to estimate the efficiency of the coated urea as a function of the statistically-significant variables. The results revealed an increase in the efficiency of the coated urea from 22% to 35% (i.e., ~59%) when prepared under the optimum process conditions.

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New coating formulation for the slow release of urea using a mixture of gypsum and dolomitic limestone

Cited by 51 publications

References 15 publications

Changes in Land Use and their Effects on Soil Properties in Huixian Karst Wetland System

Changes in Land Use and their Effects on Soil Properties in Huixian Karst Wetland System

Biodegradable Polymer Coated Granular Urea Slows Down N Release Kinetics and Improves Spinach Productivity

Response Surface Method in the Optimization of a Rotary Pan-Equipped process for Increased Efficiency of Slow-Release Coated Urea

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