Controlled‐Release Fertilizer: A Review on Biopolymers‐Based Composite, Fabrication, and Application

The imbalance in nutrient release from conventional fertilizers and plant nutrient uptake leads to a surplus accumulation of nutrients in the soil. A key approach to tackle this issue involves the engineering of nano-enabled fertilizers for the controlled release of nutrients to crops. In this context, it is important to understand the strategies for designing and utilizing nano-enabled fertilizers that can effectively regulate nutrient release and enhance nutrient use efficiency (NUE). This review focuses on nano-structured materials that serve as nutrient carriers: nano-clays, hydroxyapatite (HA) nanoparticles, mesoporous silica, carbon-based nanomaterials, polymeric nanoparticles, and other nanomaterials. In addition, the nutrient release mechanisms in controlled release fertilizers (CRFs)/slow-release fertilizers (SRFs) are discussed. The discussion and perspectives presented emphasizes the need for standardized and comprehensive fertilizer evaluation systems, design of multifunctional nanomaterials, and the creation of stimuli-responsive nanocarriers to improve NUE.

Os fertilizantes de liberação lenta são usados para reduzir a frequência das adubações por disponibilizar gradualmente os nutrientes às plantas. Entretanto, a liberação de nutrientes deve coincidir com a demanda nutricional das plantas. O objetivo deste trabalho foi avaliar a disponibilidade de N, P e K e o crescimento de dois porta-enxertos de citros quando fertilizados com fertilizantes de liberação lenta e fertilizantes convencionais. Foram avaliados dois manejos de adubação em substrato comercial (com fertilizantes de liberação lenta e somente com fertilizantes convencionais), dois porta-enxertos (limoeiro 'Cravo' e tangerineira 'Sunki') e cinco épocas de avaliação (30; 60; 90; 120 e 180 dias após o replantio das mudas), com cinco repetições e duas plantas por parcela. O emprego do fertilizante de liberação lenta aumentou o diâmetro de caule, número de folhas, teores de P nas folhas e disponibilidade de P e K no substrato, quando comparado ao emprego da fertilização convencional.

The partial substitution of chemical nitrogen fertilizers with organic fertilizer and slow-release fertilizer could improve pineapple yield and nitrogen use efficiency (NUE) and decrease greenhouse gas (GHG) emissions. However, the effect of organic and slow-release fertilizer substitution strategies on the carbon footprint (CF), nitrogen footprint (NF) and net ecosystem economic benefits (NEEB) from pineapple fields in the tropics remains largely unclear. Therefore, we conducted a long-term pineapple field trial (2017–2021) for the first time with five fertilization strategies (CK: no fertilizer; F: conventional fertilization(nitrogen (N) 817 kg ha−1, phosphorus pentoxide (P2O5) 336 kg ha−1, potassium oxide (K2O) 945 kg ha−1); RF: reduction of 41.7% N, 72.0% P2O5 and 33.1% K2O on an F basis; RFO: replacement of 20% N input with organic fertilizer on an RF basis; RFOS: replacement of 15% N input with slow-release fertilizer on an RFO basis) to identify the pineapple fruit yield, NUE, CF, NF and NEEB in the tropics. The results showed that in comparison to the F treatment, the RF, RFO and RFOS treatments improved pineapple yield (7.6%, 12.4% and 26.3%, respectively), NUE (66.4%, 75.5% and 87.7%, respectively, p < 0.05) and partial factor productivity of nitrogen (PFPN) fertilizer (84.8%, 92.8% and 116.7%, respectively, p < 0.05). Additionally, of all the treatments, the RFOS treatment had the highest yield (87.8 t ha−1). N leaching (50.1–69.1%) and ammonia volatilization (21.6–26.2%) were the two primary routes for reactive nitrogen (Nr) loss. The field soils (36.8–45.7%) and N fertilizer production and transportation (21.2–29.5%) dominated the GHG emissions. Compared to the F treatment, the RF, RFO and RFOS treatments showed decreases in Nr losses, NF, GHG emissions and CF of 36.6–41.1%, 43.3–51.9%, 19.0–29.1% and 24.5–41.7%, respectively. Of all the treatments, the RFOS treatment had the lowest CF (191.8 kg CO2eq ha−1 season) and NF (1.9 kg N t−1 season). Additionally, the NEEB of the RF, RFO and RFOS treatments improved by 13.0–39.9% over that of the F treatment. The RFOS treatment (54,880 USD ha−1) resulted in the highest NEEB of all treatments. Therefore, the substitution of conventional inorganic fertilizers with organic and slow-release fertilizers is an effective method for achieving sustainable pineapple production. However, a process for further reducing GHG emissions from farmland soils and Nr losses from organic fertilizer addition still need attention in terms of pineapple production.

Occupational safety assessment of biogenic urea nanofertilisers using in vitro pulmonary, and in vivo ocular models

The aim of this study was to assess the possibility of using slow-release fertilizers under intensive vegetable cultivation. To achieve the set research objective, a field experiment was set up in 2017, where slow-release fertilizer (NPK (%) 20-10-10+4MgO) was applied. The experiment comprised three levels of fertilization with the use of slow-release fertilizers, the control without fertilization, and the control fertilized with conventional fertilizers. The slow-release fertilizer was applied directly under each plant and in rows – approximately 8 cm below the root level. The designed systems were evaluated based on the size of commercial yield, productivity index, agronomic efficiency index, removal efficiency index, and physiological efficiency index. The results obtained in the field experiment indicate that the highest plant yield (54.22 Mg of commercial yield∙ha−1) was obtained at the highest dose of slow-release fertilizers (600 kg∙ha−1 applied in rows approximately 8 cm below the root level). In the case of direct fertilization, in the treatment with the highest dose of slow-release fertilizer, a reduction in yield was observed. The best results, in terms of equalizing the mass of individual roots, were obtained under conventional fertilization. The most favorable value of the productivity index was obtained in the variant where 400 kg∙ha−1 slow-release fertilizer was applied directly, while in the case of row application the best results were obtained at the dose of 600 kg∙ha−1. Celeriac fertilization with slow-release fertilizers under root may result in producing a yield of bigger differences in root mass, compared to conventional fertilization system.

ABSTRACTA novel slow-release potassium fertilizer (SPF) was synthesized using Pidgeon magnesium slag (PMS) and potassium carbonate, which could minimize fertilizer nutrient loss and PMS disposal problems. Orthogonal experiments were conducted to determine the optimum conditions for synthesis. The potassium (K)-bearing compounds of SPF existed mainly in the form of crystalline phases Ca1.197K0.166SiO4, K2MgSiO4, and K4CaSi3O9, and in the noncrystalline phase. The active silicon content of SPF was 2.09 times as much as that of magnesium slag, and the slow-release character of SPF met the requirement for partly slow-release fertilizer in the national standard (GB/T23348-2009). The best models for describing the K release kinetics in water and 2% citric acid were the Elovich model and the first-order model, respectively. The heavy metal contents of SPF conformed to the national standard for organic–inorganic compound fertilizers, and the leaching mass concentrations of heavy metals and Fluorine were far lower than the limit values of the identification standard for hazardous waste identification for extraction toxicity (GB5085.3-2007), and also met the class II quality standard for ground water. The environmental risk of SPF is therefore very low, but because SPF is alkaline, its effect on soil pH should be taken into account.Implications: PMS is the solid waste resulting from the production of magnesium metal by Pidgeon’s reduction process. Utilization of PMS in the high-technology and high-value areas may promote the high-efficiency development of worldwide collection metallic magnesium industry and contribute to the reduction of emissions of fine dust to air. This paper presents one of the new techniques in the use of PMS as a slow-release fertilizer by adding K2CO3. The product can serve as a very cost-effective and reliable artificial fertilizer.

Fertilizer is one of the most important elements of modern agriculture. However, conventional fertilizer, when applied to crops, is vulnerable to losses through volatilization, leaching, nitrification, or other means. Such a loss limits crop yields and pollutes the environment. In an effort to enhance nutrient use efficiency and reduce environmental pollution, an environmental smart fertilizer was reported in the current study. Poly(aspartic acid) and a degradable macro-cross-linker based on l-aspartic acid were synthesized and introduced into the fertilizer as a superabsorbent to improve the fertilizer degradability and soil moisture-retention capacity. Sustained release behavior of the fertilizer was achieved in soil. Cumulative release of nitrogen and phosphorus was 79.8% and 64.4% after 30 days, respectively. The water-holding and water-retention capacities of soil with the superabsorbent are obviously higher than those of the control soil without superabsorbent. For the sample of 200 g of soil with 1.5 g of superabsorbent, the water-holding capacity is 81.8%, and the water-retention capacity remains 22.6% after 23 days. All of the current results in this study indicated that the as-prepared fertilizer has a promising application in sustainable modern agriculture.

Integration of multi-omics approaches for understanding the Maize (Zea mays L.) foliar priming responses to Nano-urea plus (NUP) colloidal liquid fertilizer

With global food security central to United Nations Sustainable Development Goals (UN SDGs), a growing population and shrinking resources are intensifying pressure on agriculture. To sustain productivity amidst declining soil fertility, biodiversity loss, increasing pest and disease incidences, and environmental degradation, agricultural science must refine technologies and adopt a sustainable approach that balances innovation with responsible resource use. Additionally, agriculture significantly contributes to climate change, accounting for a notable share of global greenhouse gas emissions. Zeolites, a group of versatile crystalline aluminosilicates, offer a promising solution to these challenges. Their properties as ion exchangers, water absorbers, and slow-release nitrogenous fertilizers can enhance agricultural sustainability. Zeolites can improve nitrogen use efficiency, enhance soil structure, and mitigate saline soil conditions by retaining nutrients and water and releasing them slowly to plants. This reduces the need for chemical fertilizers and improves resource use efficiency. However, the widespread use of zeolites in agriculture requires careful consideration. Mapping zeolite deposits is essential for sustainable extraction and use. Potential risks such as toxic surfactant leaching must be evaluated to prevent environmental contamination. Comprehensive field experiments are necessary to understand the long-term effects of zeolite application on soil health, microorganisms, and fauna in the rhizosphere. In conclusion, zeolites hold significant promise in promoting sustainable agricultural practices by improving soil health, enhancing nutrient use efficiency, and mitigating environmental impacts. Rigorous research is needed to ensure their safety and efficacy, integrating zeolites into agricultural systems for sustainable productivity and to address the challenges of traditional intensive farming.

Review of current trends in chitosan based controlled and slow-release fertilizer: From green chemistry to circular economy

Aim:The objective of this study is to evaluate the impact of foliar fertilizer application as a supplement to conventional inorganic fertilization on rice (Oryza sativa L.) yield.The research aims to assess whether the integrated use of foliar and soil-applied fertilizers can enhance nutrient use efficiency, promote physiological responses, and ultimately improve grain yield.This study sought to contribute to the development of more efficient and sustainable nutrient management strategies in rice production systems. Methodology:The study was conducted on a 476 m rice field located in Ramon, Isabela, Philippines, ideal for rice cultivation.The hybrid rice variety LP 937 was selected for the experiment.A Randomized Complete Block Design (RCBD) was employed to assess the effects of different treatments, with three replications to ensure statistical reliability.The experimental area was divided into three blocks, each measuring 11 m 24 m, and further subdivided into eight plots of 3 m 4 m.Spacing between plots was maintained at 1.5 meters, and a 1-meter gap was left between blocks to minimize interference and facilitate management.Results: The application of the recommended fertilizer rate combined with foliar micronutrients (Treatment 6) produced the tallest plants, although differences were not statistically significant across all treatments.No significant differences were observed for tiller number, panicle length, filled grains, or 1000-seed weight.However, Treatment 5 (RCM + foliar Zn, Ca, B) showed the highest grain yield (4.17 kg/sampling area) and a 12.29% yield increase compared to the control (Farmer's practice). Conclusion:This study demonstrates the potential of integrating RCM-based fertilization with targeted foliar micronutrient application (Zn, Ca, B) to enhance rice yield.The 12.29% yield increase observed in Treatment 5 suggests that this approach can be a valuable strategy for improving rice productivity.Further research is needed to optimize the timing and rates of foliar application under varying environmental conditions.

A field experiment was conducted during Rabi season of 2022-23 at Agricultural Research Farm, Department of Agronomy, R.B.S. College, Bichpuri, Agra (U.P.) the investigation entitled ‘Enhancing nutrient use efficiency through nano-fertilizer in Barley (Hordeum vulgare L.)’. The variables involved in this study were T1 (Control (P+K) only),T2 (Control (P+K) only+ 1000 ml NN/ha at 30-35 DAS+1000 ml NN/ha at 60-65 DAS), T3 (50% RDN+500 ml NN/ha at 30-35 DAS+500 ml NN/ha at 60-65 DAS), T4 (50% RDN+1000 ml NN/ha at 30-35 DAS+1000 ml NN/ha at 60-65 DAS), T5 (75% RDN+500 ml NN/ha at 30-35 DAS+500 ml NN/ha at 60-65 DAS), T6 (75% RDN+1000 ml NN/ha at 30-35 DAS+1000 ml NN/ha at 60-65 DAS), T7 (RDN+500 ml NN/ha at 30-35 DAS+500 ml NN/ha at 60-65 DAS), T8 (RDN+1000 ml NN/ha at 30-35 DAS+1000 ml NN/ha at 60-65 DAS) and T9 (Recommended doses of fertilizers). These 9 treatments were compared in a “Randomized Block Design” with three replications. The experimental result revealed that 100% RDN (@ 60 kg ha-1) when applied with two spray of nano-nitrogen fertilizer @1000 ml ha-1 at 30-35 and 60-65 DAS (T8) played a vital role for overall improvement in crop growth and development and the maximum grain yield (56.88 q ha-1) and maximum net return was obtained with crop fertilized with 100% RDN + two foliar sprays of nano-nitrogen fertilizer @1000 ml ha-1 at 30-35 and 60-65 DAS followed by T7 (100% RDN + foliar spray of nano-nitrogen fertilizer @ 500 ml ha-1 at 30-35 and 60-65 DAS). The maximum net return ₹ 120448 ha-1 and B:C ratio (3.71) were also obtained.

The study determined the effect of using FertiGroe® Nano N (18-0-0), Nano P (0-18-0), and Nano K (0-0-38) nanofertilizers on the growth and nutrient use efficiency of tissue-cultured ‛Saba’ banana (Musa ABB) plantlets. For 7 wk, conventional fertilizers (CF) and FertiGroe® nanofertilizers (NF) were applied to the plantlets at graduated level of the recommended rate (RR). Vegetative growth was monitored weekly. At the end of the experiment, samples were collected for dry matter partitioning and leaf tissue analysis. Fertilizer treatment significantly improved pseudostem growth and dry matter production of ‛Saba’ banana plantlets. Plantlets applied with neither conventional fertilizer (CF) nor nanofertilizer NF (control) produced significantly shorter and thinner pseudostem, and less dry matter compared to plantlets that were applied with NF or CF, regardless of the recommended rate (RR) used. Despite having significantly shorter and thinner pseudostem, plantlets applied with NF at 50% RR and 75% RR produced dry matter comparable to plantlets applied with CF at 75% RR and 100% RR by allocating more dry matter to the leaves. Foliar P concentration was not limiting to the plants and its nutrient concentration in the leaves did not vary significantly across the treatments. N uptake was highest in plantlets applied with NF at 75% RR (0.187 g) and CF at 75% RR (0.158 g), 100% RR (0.167 g) and 125% RR (0.173 g). K uptake was highest in plantlets that received NF at 50% RR (0.355 g) and 75% RR (0.358 g) and CF at 75% RR (0.353 g). Nutrient use efficiency of the plantlets was measured using apparent nutrient recovery. Apparent potassium recovery of the plantlets applied with NF was higher compared to that of plantlets applied with CF. The computed optimum RR for FertiGroe® N nanofertilizer was 23.5% lower than the computed optimum RR for CF. FertiGroe® N nanofertilizer can also increase apparent nitrogen recovery by 36.87% compared to CF.

Nutrient use efficiency (NUE) in mulberry (Morus spp.) has emerged as a critical determinant of sericulture sustainability, influencing both leaf nutritional quality and cocoon productivity. Conventional fertilizer regimes, while productive in the short term, are increasingly constrained by nutrient imbalances, soil degradation, and environmental losses. Recent innovations provide a multi-dimensional framework for improving NUE in mulberry systems. Nano-fertilizers enable slow release and targeted nutrient delivery, reducing leaching and synchronizing supply with plant demand. Biofertilizers and microbial inoculants improve nutrient solubilization, uptake, and stress tolerance, offering biological routes to reduce chemical dependence. Integrated nutrient management (INM) approaches further combine conventional fertilizers, organic manures, and biofertilizers to balance productivity with soil health. Agronomic interventions—including optimized irrigation and fertigation, strategic pruning and harvesting, and soil amendments such as compost, biochar, and recycled sericulture waste—create synergies that enhance nutrient availability and leaf quality. Future prospects point toward convergence of nano-technologies, microbial consortia, and precision agronomy, supported by robust field trials, standardized regulatory pathways, and farmer-participatory models. Together, these approaches can significantly raise NUE, improve silk yield and quality, and lower the environmental footprint of sericulture.

Biosolids are rich in plant nutrients and are a byproduct of municipal wastewater treatment and those that meet strict government safety standards can be land applied in most agricultural settings except for the U.S. Department of Agriculture (USDA) certified organic production. Across the United States, about 60% of biosolids are land applied, but in Mississippi almost no biosolids are land applied. Our research goal was to compare plant size in southeastern U.S. soils amended with biosolids at rates of 2, 8, 14, and 20 tons/acre in contrast to soils amended with synthetic fertilizers using ‘Floral Lace Cherry’ dianthus ( Dianthus chinensis ×barbatus ), ‘Dreams Coral Morn’ petunia ( Petunia ×hybrida ), ‘Pidgeon White’ kale ( Brassica oleraceae var. acephala ), and ‘Bright Lights’ swiss chard ( Beta vulgaris ssp. cicla ). To accomplish this, fertilizers and biosolids were applied to prebedded fields in a randomized complete block design with a split-plot arrangement of nutrient treatments. Plant performance data and soil data were taken 43 and 56 days after transplant. Soil pH was reduced and organic matter increased at the highest application rates (14 and 20 tons/acre) of biosolids, and higher levels of phosphorus, zinc, and sulfur were found in these soils. In plant shoots, higher levels of copper, manganese, magnesium, and zinc were found when grown in soils amended with biosolids at a rate of 20 tons/acre compared with plants grown with synthetic fertilizers. Except for swiss chard, no crops fertilized with biosolids exhibited a difference in dry weights (DW) compared with conventional fertilizers. These data demonstrate that soil properties can be improved and similar plant sizes can be achieved through biosolid applications. We conclude that Grade A biosolids produced in Mississippi can be used to supplement synthetic fertilizers for ornamental and vegetable production.