Abstract
Slow-release fertilizers (SRFs) play a crucial role in agricultural practices, as they are specifically designed to optimize nutrient release and enhance crop nutrient delivery over an extended period. By effectively managing nutrient release, SRFs contribute to improved fertilizer efficiency and efficacy, ultimately reducing nutrient loss and promoting more efficient utilization of plant nutrients. Regarding production, SRFs can be generated through two primary methods: matrix-based and coated formulation approaches. The coated method, in particular, utilizes various technological processes such as fluidized bed, pan coater, rotary drum, melting and extrusion, inverse suspension polymerization, solution polymerization/cross-linking, and microwave irradiation. The global demand for sustainable agricultural practices has led to a substantial increase in the production and adoption of SRFs. Given its significant oil and gas resources, Iran is uniquely positioned to produce SRFs with a sulfur coating at a cost advantage compared to other nations. This study offers comprehensive insights into the manufacturing processes, advantages, and limitations of SRFs and emerging production trends worldwide.

Introduction
The planet's population is increasing daily, which has caused an increase in the demand for food. Fertilizers are essential for increasing crop yields. Nitrogen, phosphorus, and potassium are vital nutrients for plant growth, with nitrogen being one of the most challenging to obtain. Typically, nitrogen used as fertilizer in agriculture will be lost through various pathways, such as water dissolution, oxidation and regeneration, sublimation, nitrification, and denitrification. These losses reduce the yield and quality of the product and cause severe problems for the environment and human health. In addition to economic loss, nitrogen waste causes air and water pollution, greenhouse gas emissions, eutrophication, and many diseases such as cancer.
The excessive use of fertilizers leads to eutrophication in water, its main harmful consequence. This increases algae and aquatic plants, leading to a decline in water quality and degradation of the water environment. Eutrophication creates an environment without oxygen, making the water unsuitable for drinking, causing decreased in aquatic species and issues with odor.
The high solubility of nitrogen fertilizer in water leads to nitrogen absorption, in the form of nitrate and ammonia, by plant roots. However, the roots cannot immediately absorb a significant portion of nitrate and ammonia, leading to their entry into surface and underground waters. Moreover, excessive use of nitrogen fertilizers in arid areas results in crop contamination with nitrates and nitrites. The body absorbs nitrate from drinking water in the intestinal tract. Once inside the body, nitrate is quickly distributed throughout the tissues. About 25% of the ingested nitrate is secreted into saliva and then converted to nitrite by oral microflora. The swallowed nitrate and nitrite then return to the stomach. Nitrate serves as a precursor for creating N-nitroso compounds. Tragically, long-term consumption of food and water contaminated with nitrates and nitrites can lead to serious health conditions, including cancer, methemoglobinemia, heart attacks, lung and respiratory issues, and adverse pregnancy outcomes. These health risks underscore the need for a change in our fertilizer practices.
This article mentions the importance of using nitrogen fertilizers and their production and consumption in Iran and the world. Then, SRFs are introduced, and their production methods are briefly described. The following explains the importance of using SRFs and their disadvantages. Then, the world's approach to SRFs is analyzed with statistics. In other words, the main goal of this article is to show the tendency to produce and use SRFs worldwide.

Materials and Methods
To evaluate the impact of SRFs, a comprehensive search was conducted using the keywords Slow and Controlled-release fertilizers, Production of nitrogen fertilizers, consumption of nitrogen fertilizers, and Coated and Matrix fertilizers across Google Scholar, ScienceDirect, ResearchGate, Scopus, and ACS databases. The dataset included various articles, books, and organizational reports, primarily focusing on recent scientific research published in these databases. Additionally, production statistics used in this research were obtained from Iran's Ministry of Agricultural Jihad.

Conclusions
The global market of coated fertilizers is predicted to increase at a compound annual growth rate of 7.2% between 2023 and 2028. It is predicted that the financial turnover of the fertilizer production industry will reach 5.9 billion dollars in 2028. Therefore, Asia-Pacific, North America, and Europe will have a more significant share of coated fertilizers. Yara International ASA in Norway, Nutrien Ltd in Canada, ICL Group Ltd, Haifa Production Group, and Kingenta Ecological Engineering Group of China are among the world's largest companies producing coated SRFs. Among the most commonly coated fertilizers are urea coated with sulfur, urea coated with a polymer, and urea coated with sulfur and polymer. The amount of production of SRFs depends on the type of coating, thickness, and quality of the fertilizer grains.
China produces about 36% of the world's coated fertilizer using sulfur. 25% of its fertilizers are made in India using gypsum, 15% in Brazil with bentonite, 10% in Russia with the help of talc, and other countries produce the remaining 14%. Several Iranian companies are also active in urea fertilizer with sulfur coating. Amot Iranian Trading Company, Sabz Biomedicals Company, Salaf Shimi Company, Lordegan Urea Fertilizer Company, and Sarkhas Petrochemical are active in this field. Considering the many benefits of SRFs and the abundance and cheapness of sulfur in Iran, a more serious investment is expected to be made.
SRFs have revolutionized the agricultural industry by providing a sustainable and environmentally friendly alternative to traditional fertilizers. These innovative fertilizers release nutrients slowly and consistently, improving crop performance, reducing environmental pollution, and minimizing surface and underground water source contamination. The global production of SRFs is on the rise. Iran benefits from this trend due to its abundant oil and gas resources, which can be utilized to produce cost-effective sulfur-based SRFs. Furthermore, the country's wood and paper factories can serve as a viable source of lignin for manufacturing these fertilizers. Research findings have highlighted the potential of this biopolymer for creating SRFs with an extended-release period. To fully leverage the advantages of SRFs in Iran, it is crucial to educate farmers about their benefits and garner support from investors and industrialists to foster the development of this vital product. With the necessary backing and investment, Iran has the potential to emerge as a frontrunner in the production and application of SRFs, thereby contributing to a more sustainable and eco-friendlier agricultural sector.