Preparation and characterization of potassium nitrate controlled-release fertilizers based on chitosan and xanthan layered tablets

2013 ◽  
Vol 130 (4) ◽  
pp. 2422-2428 ◽  
Author(s):  
Mariana A. Melaj ◽  
Marta E. Daraio
Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1295
Author(s):  
Tariq Labbilta ◽  
Mohamed Ait-El-Mokhtar ◽  
Younes Abouliatim ◽  
Mehdi Khouloud ◽  
Abdelilah Meddich ◽  
...  

Four different phosphate glass formulations (F0, F1, F2, and F3) were developed according o wheat nutrient requirements to be used as controlled-release fertilizers. These glasses contain macro-elements (P2O5-K2O-CaO-MgO), with the addition of microelements (Fe-Mn-Zn-B-Cu-Mo) in each formulation. The effects of these elements’ addition on thermal properties, glass structure, and dissolution behaviors were investigated. Results showed that these glasses are composed essentially of metaphosphate chains and that the addition of micronutrients could change the chemical durability of phosphate glasses. A greenhouse experiment was performed using wheat (Triticum durum L.) to evaluate the efficiency of the four glasses, with or without application of chemical nitrogen (N) (N + VF and VF, respectively). The different formulas were tested using two rates of 0.3 and 1 g per plant. In addition to the vitreous fertilizer formulations, two other treatments were applied: control treatment with no amendment and Nitrogen-Phosphorus-Potassium treatment with the application of the conventional fertilizers on the base of optimal rates. After four months of cultivation, vitreous fertilizers application significantly improved growth (7% to 88%), photosynthetic (8% to 49%) parameters, and yield (29% to 33%) compared to NPK treatment and to the control. It has been found that formulas F1, F2, and F3 may constitute a potential alternative to conventional fertilization due to their positive impact on wheat production and can be used in practice as an environmentally controlled-release fertilizer.


Processes ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 417 ◽  
Author(s):  
Cong Jia ◽  
Panfang Lu ◽  
Min Zhang

In this work, a novel bio-based polyurethane (PU) was synthesized by using a leftovers (SF)-based polyol and isocyanate for controlled release fertilizers (CRFs). Its chemical structure, surface elemental compositions and distribution were examined by Fourier transform infrared (FTIR), energy dispersive spectroscopy (EDX) and a multifunctional imaging electron spectrometer (XPS). The microstructure morphology of CRFs were examined by SEM. The nutrient release behaviors of CRFs were observed in water. The results demonstrated that SF-based PU-coated urea (FPU) had a denser structure and better nutrient releasing ability. Findings from this work indicated that the use of SF as a coating material of environment-friendly CRFs had great potential, and would hopefully be used for horticultural and agricultural applications.


2020 ◽  
Vol 20 (3) ◽  
pp. 616
Author(s):  
Salih Muharam ◽  
Afria Fitri ◽  
Lela Mukmilah Yuningsih ◽  
Yulia Mariana Tessa Ayudia Putri ◽  
Isnaini Rahmawati

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.


1998 ◽  
Vol 16 (3) ◽  
pp. 182-188
Author(s):  
Kelly M. Groves ◽  
Stuart L. Warren ◽  
Ted E. Bilderback

Abstract Rooted cuttings of Cotoneaster dammeri Schneid ‘Skogholm’ and seedlings of Rudbeckia fulgida Ait. ‘Goldsturm’ were potted into 3.8 liter (4 qt) containers in a pine bark:sand (8:1 by vol) substrate incorporated with 3.5 g (0.12 oz) N per container provided by one of the following five controlled-release fertilizers (CRFs): Meister 21N–3.5P–11.1K (21–7–14), Osmocote 24N–2.0P–5.6K (24–4–7), Scotts 23N–2.0P–6.4K (23–4–8), Sustane 5N–0.9P–3.3K (5–2–4) or Woodace 21N–3.0P–9.5K (21–6–12). Two hundred ml (0.3 in), 400 ml (0.6 in), 800 ml (1.1 in) or 1200 ml (1.7 in) of water was applied once daily (single) or in two equal applications with a 2 hr interval between applications (cyclic). Substrate solutions were collected from containers of cotoneaster 15, 32, 45, 60, 74, 90, 105, and 119 days after initiation (DAI). Irrigation efficiency [(water applied − water leached) ÷ water applied] was determined on the same days. Cyclic application improved irrigation efficiency at 800 ml (1.1 in) and 1200 ml (1.7 in) ≈ 27% compared to a single application. Irrigation efficiencies averaged over the season were 95%, 84%, 62%, and 48% for cotoneaster and 100%, 90%, 72%, and 51% for rudbeckia at 200 ml (0.3 in), 400 ml (0.6 in), 800 ml (1.1 in) and 1200 ml (1.7 in), respectively. NH4-N and NO3-N and PO4-P concentrations in substrate solution decreased with increasing irrigation volume regardless of CRF. Substrate NH4-N concentration decreased throughout the season with most CRFs below 5 mg/liter by 90 DAI. CRFs mainly affected substrate NH4-N and NO3-N concentrations when irrigated with 200 ml (0.3 in) or 400 ml (0.6 in). Substrate NH4-N, NO3-N, and PO4-P solution concentrations were similar for all CRFs at irrigation volume of 1200 ml (1.7 in). Osmocote, Scotts, and Woodace maintained relatively constant substrate solution levels of PO4-P through 60 DAI. By 90 DAI, substrate PO4-P levels were similar regardless of irrigation volume or CRF. Substrate PO4-P concentrations were never in the recommended range of 5 to 10 mg/liter when irrigated with 800 ml (1.1 in) or 1200 ml (1.7 in) regardless of CRF. Solution pH remained in the recommended range of 5.0 to 6.0 for all irrigation volumes and CRFs throughout the entire study with the exception of Sustane.


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