In modern agricultural production, solid granular fertilizers, with their stable physical form and excellent adaptability, have become the most widely used fertilizer category. They are not only carriers of nutrients but also key media for achieving efficient, large-scale agricultural operations. From vast wheat fields to precise orchard management, these uniformly shaped granules support global grain and vegetable production with their unique advantages.

Classification by Form: Size and Structure Define Function

Solid granular fertilizers are not all the same; their particle size and internal structure determine different uses and effects.

1. Large-Granule Fertilizers
This is the most common form, such as the familiar urea, diammonium phosphate (DAP), and general compound fertilizers. Their granules typically have a diameter of 2-4 mm and are firm and dense. This design makes them resistant to breakage, moisture absorption, and caking, with even nutrient distribution. The advantage of large granules lies in their “longevity.” They dissolve relatively slowly and are primarily used as base fertilizers, deeply incorporated into the soil to provide a stable supply of basic nutrients throughout the crop’s growing season, while also reducing losses from rainwater leaching.

2. Small-Granule / Bulk Blended (BB) Fertilizers
These fertilizers have smaller particle sizes (1-2 mm) and are physically blended from single-nutrient granules (e.g., white nitrogen granules, red potassium granules) in specific ratios, hence the name “BB fertilizers.” Their core advantage is formulation flexibility. Growers can customize the N-P-K ratio according to the needs of different crops and growth stages. They can be used both as base fertilizers and for mechanized precision top-dressing, making them an ideal choice for variable rate application and nutrient management.

3. Coated Granular Fertilizers
This represents an advanced product of fertilizer technology, such as polymer-coated urea or sulfur-coated urea (SCU). By coating a regular fertilizer granule with a functional membrane (sulfur, polymer, etc.), they achieve precise control over the nutrient release rate. The thickness of this “coat” determines whether nutrients are released slowly over weeks or months. These fertilizers are mainly applied once as a base fertilizer, achieving “one-time application, full-season supply,” greatly saving labor and significantly improving nutrient use efficiency while reducing environmental pollution risks.

Core Advantages: Why is the Granular Form So Popular?

The widespread adoption of solid granular fertilizers stems from their comprehensive advantages:

Excellent Physical Stability: The compact granular form makes them less prone to moisture absorption and caking, resulting in minimal loss during long-distance transport and storage, a long shelf life, and suitability for large-scale warehousing and trade.

Perfect Compatibility with Mechanization: The uniform particle size is the “perfect partner” for modern agricultural machinery. They can be accurately broadcast or placed by seeders and fertilizer applicators, enabling combined seeding and fertilizing, drastically improving operational efficiency and reducing labor costs, especially on large-scale flat farms.

Flexible Application Methods: Whether it’s base fertilizer requiring deep incorporation or precision side-dressing for top-dressing, the granular form is up to the task. From broadcasting and banding to hole application, it covers almost all scenarios, from field crops to horticultural crops.

Controllable Nutrient Release: By adjusting granule size or adding coatings, the dissolution rate of the fertilizer in the soil can be scientifically regulated. This allows the nutrient release curve to better match the crop’s uptake pattern, avoiding the drawbacks of quick-release fertilizers (a sudden burst followed by insufficiency) and achieving more sustained and efficient nourishment.

Scientific Application: The Art of Method and Placement

Correct application methods are key to realizing the efficacy of granular fertilizers, distinguishing between base and top-dressing:

Base Fertilizer Application: The goal is “deep and even.” Common methods include broadcasting followed by plowing (evenly spreading fertilizer on the soil surface and then plowing it into the 15-20 cm soil layer) or banding (placing fertilizer in a trench beside the planting row). For fruit trees, hole application is used, placing fertilizer in the root concentration zone.

Top-Dressing Application: The core principle is “close but avoid roots.” Common methods include side-dressing or furrow application, where a shallow trench is dug beside the crop roots, fertilizer is placed, and then covered with soil. This makes nutrients accessible to the roots while preventing direct contact that could cause “fertilizer burn.” For fruit trees, top-dressing is often done by digging holes near the “drip line” at the outer edge of the canopy projection.

Key Considerations

Match the Type to the Purpose: Large granules are suitable for deep placement as base fertilizer; small granules/BB fertilizers are suitable for shallow placement as top-dressing; coated fertilizers must never be crushed, as this completely destroys their controlled-release function.

Always Incorporate into Soil: Especially for ammonium-based nitrogen fertilizers like urea, if broadcast without timely incorporation or soil cover, nitrogen will volatilize into the air in large quantities, causing waste and pollution.

Maintain a Safe Distance: When top-dressing, fertilizer should be placed in the active root zone to the side, maintaining a distance of 5-10 cm from the plant to avoid direct contact.

In summary, solid granular fertilizers are an indispensable part of the modern agricultural production system. With their standardization, ease of use, and efficiency, they closely integrate nutrient management with modern agricultural technology, providing a solid material foundation for ensuring global food security and the sustainable development of agriculture.

From Powder to Pellet: The Engineering of Modern Fertilizer

The diverse forms and precise characteristics of solid granular fertilizers are the direct result of advanced fertilizer granulation technology. These fertilizer granulation processes are executed by specialized professional fertilizer manufacturing equipment. The choice of technology is crucial. For many standard NPK blends, wet granulation using a rotary drum granulator is common, often integrated into a disc granulation production line for shaping uniform pellets. This method is a core part of the standard npk manufacturing process.

In contrast, the production of dense, slow-release granules often relies on dry fertilizer granules compaction, utilizing a fertilizer compaction machine as the core of a roller press granulator production line. This highlights the engineering precision behind the scenes: each fertilizer type—from basic granules to sophisticated coated products—is manufactured using a tailored granulation pathway. This sophisticated industrial foundation ensures that farmers worldwide receive reliable, high-performance fertilizers that are perfectly suited for mechanized application and precise soil management, ultimately supporting efficient and sustainable agricultural systems.

 Introduction: How is Good Fertilizer “Forged”?

In the field, we want nitrogen fertilizer to release slowly, nourishing crops persistently, rather than leaching or volatilizing quickly. Slow-release urea fertilizers are designed for this purpose. However, manufacturing high-quality slow-release urea granules is not a simple matter of mixing and pressing. It is more akin to a precise “culinary” process, where the raw material formulation is the recipe, and the granulation process is the heat and timing. A recent study delves into how adjusting two key “switches” in a disc granulator—binder concentration and granulation time—can precisely control the final “physical fitness” of fertilizer granules, thereby providing a scientific guide for producing more efficient and environmentally friendly slow-release urea.

I. The Core of the Study: Two Variables, Four Qualities

Imagine a rotating shallow pan where urea powder and a binder solution extracted from cassava starch are mixed and tumbled. The research team set up a clear comparative experiment: they fixed all other conditions like disc speed and inclination, and systematically changed only two factors: the concentration of the starch binder solution and the time the material spends tumbling in the pan for granulation.

They focused on these four “fitness” indicators that determine fertilizer quality:
1. Durability: Are the granules “tough” enough? Can they withstand collisions and friction during long-distance transport without turning into powder?
2. Density: Are the granules “fluffy” or “solid”? This affects the actual weight per bag of fertilizer, transportation costs, and application uniformity in the field.
3. Pelletizing Yield: How much raw material successfully turns into qualified granules? This directly impacts production efficiency and cost.
4. Water Absorption and Dispersion Time: Do the granules disintegrate quickly or release slowly upon contact with water? This is the core measure of their “slow-release” capability. We want them to dissolve like a slow-release candy, providing nutrients steadily in the soil.

II. Finding One: Binder Concentration—The “Glue” Matters

Cassava starch plays the role of “natural glue” here. The study found that the thickness of this “glue” has a decisive impact on granule quality.

When researchers increased the concentration of the starch solution, a positive chain reaction occurred: the granules’ water absorption, density, pelletizing yield, and durability all improved simultaneously. This is because a thicker starch solution forms a stronger, denser binding network around each urea particle. Just like using thicker glue for bonding, the adhesion is firmer, the structure is more compact, and the granules naturally become tougher, heavier, and have fewer internal pores.

More interestingly, granules made with higher concentration starch also “held on” longer in water. They disintegrated and released nutrients more slowly, which is the dream characteristic of slow-release fertilizers. Observations under an electron microscope showed that granules from the high-concentration group had surfaces like smooth, dense pebbles, while those from the low-concentration group had rough, porous surfaces, visually explaining the source of the performance difference.

III. Finding Two: Time—The Art of “Kneading”

Granulation time is like the kneading time when making dough. The study showed that extending the “kneading” time of the granules in the disc also led to comprehensive quality improvements.

Longer granulation time gives the powder more opportunities to collide, adhere, and round off. This results in more regular granule shapes and a more compact interior. Consequently, granule durability, density, and pelletizing yield all increased with time. Simultaneously, sufficient kneading allows the starch “glue” to distribute more evenly, forming a more complete coating. This not only slightly increases the granules’ water absorption capacity but, more importantly, extends their dispersion time in water, further optimizing the slow-release effect.

IV. Insights for Producers: How to “Customize on Demand”

This study turns complex processes into clear multiple-choice questions:

• If you want to produce high-end fertilizers with optimal controlled-release performance and superior storage/transport durability, the answer is: use a higher concentration of cassava starch binder and allow for a longer granulation time.

• If you need to strike a balance between production efficiency and cost to produce the most cost-effective product, you can utilize the data models derived from research to calculate the optimal combination of binder concentration and granulation time based on your specific requirements for granule density, strength, and release period.

It’s like mastering a precise “cooking” formula, allowing fertilizer producers to flexibly “customize” slow-release urea products with different specifications and performance according to market demand.

Optimizing Granulation: The Science Behind Consistent Fertilizer Pellets

The scientific study of binder concentration and granulation time directly applies to the core of npk fertilizer production technology. In a complete npk fertilizer production line, precise formulation using a npk blending machine ensures accurate nutrient ratios. The subsequent granulation stage, which is central to the npk fertilizer manufacturing process, leverages advanced npk granulation machine technology to transform this mix. The principles of optimizing binder properties and process timing are critical for equipment like a npk fertilizer granulator machine, whether it operates as a wet granulator or an alternative system like a fertilizer roller press machine for dry compaction.

Mastering these variables allows manufacturers to fine-tune the NPK compound fertilizer production capacity and the final product’s physical properties—such as density, strength, and dissolution rate. This level of control is essential for producing high-quality slow-release or controlled-release fertilizers. The integration of this scientific understanding into the operation of npk fertilizer granulator machine equipment demonstrates how empirical research translates into practical, scalable manufacturing excellence. It enables the production of consistent, “tailor-made” fertilizers that meet specific agronomic needs, enhancing nutrient use efficiency and supporting sustainable agricultural practices through precision engineering.

Conclusion

The power of science lies in transforming experience into quantifiable, replicable laws. This study on disc granulation process, through rigorous experimentation, reveals how two ordinary operational parameters—binder concentration and granulation time—act like levers to influence the final quality of slow-release urea granules. It not only provides a direct “operating manual” for fertilizer plants to optimize production but also brings us a step closer to the goal of producing more efficient, environmentally friendly, and intelligent “ideal fertilizers.” In the future, by exploring more “variables,” we can hope to design bespoke fertilizers, like precision instruments, perfectly tailored to the needs of every crop and every plot of soil.

In the context of global climate change, the efficient utilization of agricultural waste to achieve resource recycling has become a critical issue for sustainable agriculture worldwide. Oil palm empty fruit bunches (EFB), a major by-product of palm oil production, have long been treated as waste, decomposing naturally or being incinerated, which not only wastes resources but also exacerbates greenhouse gas emissions. However, recent studies show that properly processed EFB can serve as an excellent soil conditioner, significantly improving soil properties and increasing crop yields.

Resource Potential and Processing Methods of EFB

Globally, approximately 99 million tons of EFB are produced annually. In Ghana alone, daily EFB production reaches 390 tons. Such vast amounts of organic waste, if utilized effectively, could greatly promote sustainable agricultural development. EFB is primarily applied in four forms: direct mulching, biochar, compost, and ash. Different processing methods directly influence its effectiveness as a fertilizer.

EFB’s Role in Promoting Crop Growth

A meta-analysis of 19 studies revealed that, compared to unamended soil, EFB application increased crop growth and yield by an average of 49.2%. Among the various forms, EFB biochar showed the most significant effect, increasing yield by up to 78.4%, followed by mulching (33.8%), composting (30.9%), and ash (21.0%). When EFB was co-applied with mineral fertilizers or other materials, crop yield still increased by 16.4%.

Key Factors Influencing EFB’s Effectiveness

The yield-enhancing effects of EFB are moderated by several factors:

Experimental Environment: Effects under greenhouse conditions were superior to those in open fields, with a difference of approximately 68%, mainly due to uncontrollable environmental variables in the field.

Soil Texture: EFB showed the most significant improvement in coarse-textured soils like sandy soil, with lesser effects on clay soil, indicating its greater potential for improving impoverished soils.

Crop Type: Although effects varied slightly among crops, EFB generally had a positive impact on all crop types.

Mechanisms of EFB in Soil Improvement

EFB is rich in nutrients such as potassium and nitrogen. Its application improves soil through the following pathways:

Biochar: Enhances soil porosity, water retention, and nutrient holding capacity, particularly raising the pH of acidic soils and promoting phosphorus uptake.

Compost: Reduces the carbon-to-nitrogen ratio, promotes nutrient release, and increases soil organic matter and microbial activity.

Direct Mulching: Suppresses weeds, reduces soil erosion, and gradually releases nutrients during decomposition.

Sustainable Agriculture and Climate-Smart Choices

In resource-poor regions like sub-Saharan Africa, EFB offers smallholder farmers a low-cost, accessible soil improvement option. Moreover, converting EFB into biochar or compost contributes to carbon sequestration and emission reduction, achieving dual benefits for agriculture and the climate. For example, co-composting EFB with palm oil mill effluent can reduce greenhouse gas emissions by up to 76%.

Challenges and Prospects

Despite its promising potential, EFB application faces several challenges:

Cost-Benefit Analysis: Converting EFB into biochar or compost requires additional investment, and its economic feasibility must be evaluated based on local conditions.

Nutrient Release Dynamics: The release of nutrients from EFB is influenced by soil and environmental factors, necessitating further research for precise application.

Resource Competition: EFB can also be used as fuel or industrial raw material, requiring integrated planning for its optimal utilization.

From Waste to Resource: Industrial Pathways for OPEFB Fertilizer

The valorization of Oil palm empty fruit bunch (OPEFB) is a key strategy in sustainable agriculture, unlocking the potential of its unique oil palm empty fruit bunch composition. The most effective uses of oil palm empty fruit bunch often involve transforming it through an efficient organic fertilizer fermentation process. This requires sophisticated fermentation composting turning technology to optimize decomposition, implemented using equipment like the chain compost turning machine or for large-scale operations.

Following complete stabilization, the composted OPEFB can be integrated into a formal organic fertilizer production line. To create a market-ready product, this line typically includes a granulation stage. Innovative equipment such as a new type two in one organic fertilizer granulator efficiently mixes and shapes the material into uniform pellets. For enhanced value, this process can be configured as a bio organic fertilizer production line, inoculating the compost with beneficial microbes. This systematic approach demonstrates a complete industrial workflow for converting a major agricultural by-product into high-quality, soil-enhancing fertilizers, supporting both circular economies and climate-resilient farming.

Conclusion

The utilization of oil palm empty fruit bunches as fertilizer not only addresses waste management challenges but also provides a viable pathway for enhancing soil fertility and climate resilience in global agriculture, particularly in tropical regions. Moving forward, through deeper research, optimized technologies, and policy support, EFB is poised to play an increasingly significant role in sustainable agriculture, contributing to both food security and ecological conservation.

In the fertilizer production process, crushing is a crucial step for improving raw material uniformity and facilitating subsequent granulation. Selecting the appropriate crushing equipment based on the characteristics of different raw materials is essential. The half-wet material crusher, chain crusher, cage crusher, and horizontal crusher are four common types of specialized equipment in fertilizer processing. Although they all belong to crushing machinery, they differ significantly in terms of applicable raw materials, moisture tolerance, crushing precision, and application scenarios. This article provides an in-depth analysis of their core differences, advantages, and usage considerations, offering scientific selection and operational guidance for global fertilizer producers.

Common Principles: Core Safety and Maintenance

Regardless of the type of crusher selected, some universal safety and maintenance principles must be followed. First, controlling impurities in raw materials is critical. Foreign objects such as metal blocks and stones can severely damage core components like blades, chains, or cage bars. Therefore, it is recommended to install magnetic separators and grid screens at the feed inlet for pretreatment. Second, uniform and quantitative feeding is essential for ensuring stable equipment operation, as instantaneous overload can easily cause blockages or motor failure. Additionally, different equipment has varying tolerances for raw material moisture. Exceeding the design range can lead to material adhesion, blockages, or reduced efficiency, so raw materials should be appropriately dried or conditioned based on equipment characteristics. In terms of safety, always check fasteners before operation, lubricate bearings regularly, and clean the chamber promptly after shutdown to prevent hardening and caking. Never open the machine cover for maintenance while the equipment is running to ensure personal safety.

Feature Analysis: Unique Advantages of the Four Crusher Types

The Half-Wet Material Crusher is an expert in processing high-moisture organic materials. It can effectively handle semi-wet materials with a moisture content of 20% to 60%, such as decomposed livestock manure, straw, and biogas residue, without issues of adhesion or blockage. Its core advantages lie in its high moisture tolerance and adjustable crushing granularity (1-5 mm), often achieving the desired product in a single pass without secondary processing. This equipment operates on an impact crushing principle, relying on high-speed rotating wear-resistant alloy blades to impact and tear materials. During use, it is important to ensure that the raw material moisture content does not exceed the upper limit and to regularly inspect blade wear.

The Chain Crusher is known for its simple structure and low maintenance costs. It is suitable for processing caked raw materials with a moisture content not exceeding 25%, such as hardened organic fertilizer or returned granules. Its working principle involves high-speed rotating chain groups impacting and kneading materials, achieving both crushing and mixing effects while producing uniformly sized products. It is primarily used for coarse or medium crushing but should avoid processing overly hard lumps to prevent chain deformation.

The Cage Crusher is designed specifically for fine crushing. It excels in refining dry raw materials (moisture ≤20%), producing finely ground products with particle sizes as fine as 80-120 mesh. It operates with low noise and minimal dust. Its core mechanism involves the shearing and grinding action of a double-layer cage bar rotor. It is suitable for fine crushing of inorganic fertilizer and compound fertilizer powders but is not suitable for processing coarse or hard lumps. During operation, raw material moisture must be strictly controlled, and the gaps between cage bars should be cleaned regularly to prevent blockages that could affect precision.

Horizontal crushers are widely used and essential equipment in production. They can process various dry and wet (≤15%) raw materials, and the crushing particle size (1-10 mm) can be flexibly adjusted by changing the screen. With their large-capacity crushing chamber and high output, horizontal crushers are particularly suitable for large-scale production lines. Horizontal crushers are mainly divided into two types: hammer crushers (impact crushers) and belt crushers (kneading and mixing crushers). When processing high-fiber materials, the feed speed must be controlled to prevent entanglement.

Scientific Selection: Based on Raw Materials and Process Needs

Choosing the right crusher depends on clearly understanding the characteristics of the raw materials and the process goals of the production line. If the main task is to process high-moisture organic fertilizer materials after decomposition, the half-wet material crusher is the optimal choice. For coarse crushing tasks such as breaking up caked organic fertilizer or processing returned materials, the chain crusher is more cost-effective and efficient. When the production requires refining inorganic fertilizer or compound fertilizer raw materials into fine powders, the cage crusher should be selected. For comprehensive production lines with diverse raw material types that require handling multiple materials, the versatile horizontal crusher offers the greatest flexibility and output guarantee.

In summary, understanding the core principles and applicable ranges of each type of equipment, combined with strict daily maintenance, can not only improve the efficiency and quality of fertilizer production but also significantly extend equipment lifespan, providing solid technical support for the development of global sustainable agriculture.

From Crushing to Granulation: A Systematic Production Workflow

Selecting the appropriate crushing machine is the critical first step in preparing raw materials for efficient fertilizer production. This choice—whether a half-wet crusher for moist organics or a cage crusher for fine powders—directly impacts the quality of the mixed feed. In a complete npk fertilizer production line, the uniformly crushed materials are then precisely blended using a npk blending machine before entering the core fertilizer granulation processes.

For organic fertilizer, the chain starts with a windrow composting machine, followed by crushing, before the material enters a dedicated organic fertilizer production line or bio organic fertilizer production line. Granulation is the final shaping stage across all types. This utilizes specialized fertilizer processing machine equipment: a disc granulator for shaping is central to a disc granulation production line, while a double roller press granulator forms the core of a dry roller press granulator production line. The synergy between precise size reduction, accurate blending, and advanced granulation technologies ensures the efficient production of high-quality, application-ready fertilizers for global agriculture.

Introduction: Compost is More Than Just Fertilizer

Composting, an ancient yet modern organic waste conversion technology, has long seen its final products evolve beyond the simple concept of “mature organic matter.” Through different processing techniques and formulation designs, compost can be transformed into various fertilizer products with diverse forms and functions, meeting the varied needs from field agriculture to precision horticulture, and from soil improvement to targeted nutrition. Understanding these derived fertilizer types and the scientific principles behind them is crucial for agricultural producers to choose suitable fertilizers and achieve efficient, sustainable cultivation.

Part I: The Four Major Forms of Compost-Based Fertilizers

1. The Basic Form: Mature Bulk Organic Fertilizer

This is the most primitive and purest form of compost. After complete maturation, organic waste is used directly without additional processing. It appears dark brown or black, with a loose texture resembling fertile forest topsoil. It is rich in humus—a stable organic matter that significantly improves soil structure, increasing soil porosity and water retention. Simultaneously, it contains abundant beneficial microbial communities and slowly released basic nutrients like nitrogen, phosphorus, and potassium. This fertilizer is particularly suitable as a base fertilizer for field crops (e.g., wheat, corn) or as a soil amendment for orchards and vegetable gardens. When incorporated into the soil through tillage, it lays a healthy foundation for crop growth.

2. The Advanced Form: Granular Organic Fertilizer

To meet the needs of modern mechanized fertilization, mature compost can be converted into uniform granules through granulation processes (e.g., disc granulation, drum granulation). These granules are typically 2-6 mm in diameter, with moderate strength, facilitating transportation, storage, and precise application via seeders or spreaders. Granulation not only reduces dust during application but also controls nutrient release rate through physical form, achieving longer-lasting effects. A more advanced product is the “organic-inorganic compound fertilizer,” which incorporates fast-acting chemical fertilizers (e.g., urea) during granulation, perfectly combining the soil-improving function of organic fertilizer with the quick-release properties of chemical fertilizer.

3. The Functional Form: Bio/Functional Organic Fertilizer

This represents an intelligent upgrade of composting technology. By inoculating mature compost with specific functional microorganisms (e.g., phosphorus-solubilizing bacteria, potassium-solubilizing bacteria, biocontrol agents), the resulting “bio-organic fertilizer” not only provides nutrients but also mobilizes fixed phosphorus and potassium in the soil or suppresses soil-borne diseases. Another type, “functional organic fertilizer,” is enriched with biostimulants like humic acid, seaweed extracts, and amino acids, which directly stimulate crop root growth and enhance stress resistance. These fertilizers are “value-added” products widely used in high-value cash crops and protected agriculture.

4. The Refined Form: Organic Water-Soluble Fertilizer

Through physical or chemical methods, soluble organic components (mainly small-molecule humic acid, fulvic acid, and amino acids) are extracted from mature compost to produce liquid or powdered water-soluble fertilizers. This fertilizer type has high nutrient concentration and fast dissolution, fully compatible with modern drip irrigation, sprinkler irrigation, and fertigation systems. It can be rapidly absorbed by crops and is especially suitable for quick nutritional supplementation during critical growth stages (e.g., flowering and fruit setting), making it an ideal choice for precision agriculture.

Part II: Two Technological Pathways: Aerobic vs. Anaerobic Composting

The essence of composting is the microbial decomposition of organic matter, divided into two major technological pathways based on oxygen dependence.

Aerobic Composting: The Mainstream Efficient Process

Aerobic composting relies on aerobic microorganisms (bacteria, fungi, actinomycetes) to decompose organic matter in the presence of oxygen. This process releases significant heat, rapidly raising the pile temperature to 55-65°C within days. The high temperature not only accelerates decomposition but also effectively kills pathogens and weed seeds. Aerobic composting has a short cycle (typically 20-40 days), produces minimal odor during the process (mainly carbon dioxide and water), and yields stable product quality, making it the mainstream process for large-scale organic fertilizer production. Its success hinges on maintaining pile porosity, ensuring oxygen supply through turning or forced aeration.

Anaerobic Composting: Harvesting Both Energy and Fertilizer

Anaerobic composting occurs under strictly oxygen-free conditions, led by anaerobic microorganisms like acidogenic bacteria and methanogens. This process does not generate high temperatures, decomposition is slow, and the cycle is long (typically 3-6 months). However, it has a unique advantage: producing biogas (mainly methane), a renewable clean energy source usable for cooking, lighting, or power generation. Therefore, anaerobic composting (especially biogas projects) is popular in rural areas and small farms, achieving the triple goal of “waste treatment – fertilizer production – energy recovery.” However, it requires strict sealing, and poor management can lead to malodorous gases like hydrogen sulfide.

Part III: How to Choose the Right Composting Pathway and Product?

The choice of composting method and final product depends on specific conditions and objectives:

· For large-scale farms or organic fertilizer plants: Aerobic composting is the preferred choice for its high efficiency and high degree of product commercialization. Granular or functional fertilizers can be produced based on market needs.

· For resource-limited rural households or small ecological farms: Anaerobic composting (e.g., household biogas digesters) can treat waste while providing cooking gas, with biogas slurry and residue being high-quality liquid organic fertilizers.

· For protected agriculture and high-value crop growers: Consider using functional bio-organic fertilizers or organic water-soluble fertilizers to achieve precise, efficient nutrient management and soil health maintenance.

· For field crop producers: Basic mature bulk fertilizer or granular organic fertilizer are cost-effective options that can effectively improve soil and lay the foundation for long-term sustainable production.

Integrated Fertilizer Manufacturing: From Composting to Granulation

Modern fertilizer production encompasses two distinct yet complementary pathways. The organic fertilizer manufacturing process, rooted in advanced composting, transforms waste into stable humus. To create a commercial product, this compost is often shaped using equipment like those in a disc granulation production line. Conversely, the conventional npk fertilizer production process follows a different route. It begins with chemical synthesis and precise blending, followed by granulation. Here, technologies like drum granulation using a rotary drum granulator are common in a standard npk production line.

The choice of granulation method is critical. While wet processes like drum granulation dominate for many NPK blends, alternative technologies exist. The principle of fertilizer granules compaction is employed in dry granulation, utilizing a fertilizer compaction machine or fertilizer compactor as the core of a roller press granulator production line. This diversity in the npk manufacturing process highlights the industry’s adaptability. Whether starting from organic waste or synthetic raw materials, modern integrated systems select the optimal processing and shaping technologies to produce efficient, market-ready fertilizers that support sustainable global agriculture.