What is Pelletized Lime? Benefits, Uses, and Application Techniques

What Is Pelletized Lime?

Pelletized lime is a specially processed lime product. It is often used to adjust the pH of soil. With its porous structure, it can slowly release effective ingredients and has a long-lasting effect. It can steadily increase the pH value of soil by 0.5-1.0 units within several months. In industry, Lime pelleting product is used in desulfurization and dephosphorization processes in steel production. In the flue gas desulfurization process, lime pelletz has high reaction efficiency with sulfur dioxide, and the desulfurization rate can reach more than 90%. The generated calcium sulfate has high purity and is easy to recycle. In addition, granular lime is also used in water treatment to remove impurities in water and adjust pH value. Lime pelletized is usually made by calcining, grinding and other processes of raw materials such as limestone, and then making it into granules. Pelletized limestone has the characteristics of uniform particle size and good fluidity, which makes it more convenient to store and transport, and is not easy to agglomerate. Compared with traditional Pell lime, it has less dust, reduces dust pollution and the risk of workers inhaling, is not easy to compact during storage, and the storage period can be extended to more than 1 year. In soil improvement, Pelletized lime can slowly release effective ingredients with its porous structure, which has a long-lasting effect and can steadily increase the soil pH value by 0.5-1.0 units within a few months.

Definition and Composition:

Definition:

Granulated lime is a product that has been processed to make lime into granules. It is usually obtained from raw materials such as limestone through a series of high-temperature calcination, grinding, granulation and other processes. This form of lime has many advantages, such as good fluidity, easy storage and transportation, and more uniform dispersion during use.

Ingredients:

The main component is calcium oxide (CaO), which is usually produced by the decomposition of limestone (the main component is calcium carbonate, CaCO₃) at high temperatures. In some cases, granulated lime may also contain a small amount of impurities such as magnesium oxide (MgO), silicon dioxide (SiO₂), aluminum oxide (Al₂O₃) and iron oxide (Fe₂O₃). The content of these impurities is usually low, generally within a few percent. In addition, if the granulated lime has been specially treated or added with other ingredients, it may also contain some other trace elements or additives to meet specific usage requirements. For example, in agricultural granulated lime, some trace elements that help plant growth may be added.

Importance of Soil pH in Agriculture

Soil pH is crucial in agriculture and is directly related to crop growth, soil fertility, pest and disease control, and many other aspects.

Influence on nutrient availability:

Most plants prefer slightly acidic to neutral soil environments with a pH of 6.0-7.5. Within this range, macroelements such as nitrogen, phosphorus, and potassium, as well as trace elements such as iron, zinc, and manganese can exist in a form that is easily absorbed by plant roots. For example, when the soil pH is appropriate, phosphorus will be converted into soluble forms such as monocalcium phosphate for plant uptake; in overly acidic or overly alkaline soils, phosphorus is easily combined with iron, aluminum, or calcium to form insoluble compounds, resulting in phosphorus deficiency in plants.

Regulating soil microbial activity:

Different microorganisms have different adaptability to soil pH. Neutral soil is conducive to bacterial growth. They participate in key processes such as organic matter decomposition and nitrogen conversion. For example, ammonifying bacteria convert nitrogen-containing organic matter in the soil into ammonium nitrogen, providing nitrogen sources for plants. In acidic soil, fungal activity is relatively stronger. Although some fungi can help plants absorb nutrients, they may also breed pathogenic fungi and affect crop health.

Affecting plant growth:

Extreme soil pH values ​​will hinder plant growth. In over-acidic soil, the solubility of elements such as aluminum and manganese increases. Excessive aluminum ions will inhibit the growth of plant roots, making the root tips thicker and twisted, and hindering the absorption of water and nutrients. Over-alkaline soil is prone to physiological diseases such as iron deficiency and zinc deficiency, causing plant leaves to lose green and turn yellow, affecting photosynthesis, and reducing crop yield and quality.

Affecting soil structure:

A suitable pH value helps maintain a good soil structure. Under neutral conditions, the surface charge of soil colloids is stable, and soil particles condense to form a granular structure, enhancing soil aeration, water permeability and water retention. In acidic soils, hydrogen ions replace calcium ions on soil colloids, destroying the granular structure, making the soil compacted and affecting root extension.

What is the Importance of Soil pH in Agriculture?

Understanding Soil Acidity and Alkalinity

• Soil acidity, or soil pH, is a key indicator for measuring the relative concentration of hydrogen ions (H⁺) and hydroxide ions (OH⁻) in the soil. In the range of 0-14, 7 is neutral, below 7 is acidic, and above 7 is alkaline.
• In tropical and subtropical rainforest areas, such as the Amazon rainforest and the Congo Basin, the annual precipitation is abundant, and a large amount of rainfall continues to leach the soil, causing a large amount of alkaline salt ions such as calcium and magnesium to be lost, while the oxides of elements such as aluminum and iron are relatively enriched, hydrolyzing to produce hydrogen ions, causing the soil pH value to often be as low as 4.5-5.5, which is acidic. In this environment, the effectiveness of nutrients such as phosphorus and molybdenum in the soil is reduced, and the solubility of aluminum ions is increased, which is toxic to plant roots and inhibits plant growth. However, many acid-loving plants such as Ericaceae can grow well here.
• In arid and semi-arid areas, such as the Sahara Desert in Africa and the desert areas in central Australia, evaporation far exceeds precipitation. As water evaporates, salt in the deep soil migrates and accumulates to the surface, and the content of alkaline salts such as sodium carbonate and sodium bicarbonate increases, and the soil pH value can reach 8.5-9.5, which is alkaline.
• In an alkaline environment, trace elements such as iron, zinc, and manganese form insoluble compounds, which reduce their effectiveness and easily cause plant deficiency, affecting plant growth and development. However, some halophytes such as Suaeda salsa can adapt to such an environment.
• Soil pH has a significant impact on microbial activity. In acidic soils, fungal activity is relatively high, while bacterial activity is inhibited, affecting the decomposition of organic matter and nutrient circulation in the soil; in alkaline soils, the activity of some bacteria is limited, affecting processes such as nitrogen conversion.
• In addition, pH also affects soil structure. In acidic soils, hydrogen ions replace base ions on soil colloids, destroying the structure of soil aggregates and reducing the soil's ability to retain water and fertilizer; in alkaline soils, soil particles are dispersed due to the action of sodium ions, making them easy to compact and causing poor ventilation and water permeability.

Role of Lime in Soil pH Adjustment

• Lime plays a key role in regulating soil pH. About 30% of the world's arable land is acidic. The calcium oxide and calcium hydroxide contained in lime can neutralize hydrogen ions in the soil. For example, in Brazilian coffee gardens, 2 tons of lime per hectare were applied, and the pH value rose from 4.8 to 5.5, and the yield increased by about 20%. At the same time, lime can make soil colloids absorb calcium ions and increase the cation exchange capacity.
• In temperate vegetable greenhouses, 5-10 kilograms of lime per cubic meter were applied, and the cation exchange capacity increased by 10%-20%, and the pH fluctuation was controlled within ±0.3, which played a role in buffering the changes in soil acidity and alkalinity.
• In addition, lime can adjust the pH value, which is beneficial to the growth and reproduction of bacteria. For example, after applying lime to acidic grasslands in the UK, the pH value rose from 5.0 to 6.5, the number of nitrifying bacteria increased by about 5 times, and the fresh grass yield increased by about 30%.
• Ultimately, the purpose of regulating soil pH, improving the environment, and increasing fertility was achieved, which is of great significance to agricultural production and soil ecological maintenance.

How Pelletized Lime Is Manufactured?

1. Raw material selection

The main raw material for making pelletized lime is high-quality limestone, whose calcium carbonate (CaCO₃) content must be more than 90% and the impurity content must be extremely low, so as to ensure the high quality of the produced lime. Some large lime production companies in the United States, for example, mine limestone from specific mining areas, where the average calcium carbonate content of limestone is stable between 93% and 95%.

2. Pelletized Limestone Grinding&Mixing

Grinding is an important step in the manufacturing process of Pellet lime. It is usually carried out after calcination and before granulation. Its purpose is to further process the calcined lime blocks into finer powder to meet the requirements of subsequent production processes.

Feed particle size:

The particle size of the lime blocks entering the grinding equipment is generally required to be around 5-30 cm. After the initial crushing process, the larger limestone blocks are crushed to a suitable feed particle size to ensure the grinding effect and the normal operation of the equipment.

Grinding time:

The grinding time is determined according to the required product fineness and output. Generally speaking, the grinding time of ball mill is long, which may take several hours or even longer, while the grinding time of Raymond mill is relatively short, usually between tens of minutes and hours. For example, for the production of pellet lime for agricultural soil improvement, the powder fineness is required to reach about 100-200 meshes. When using Raymond mill for grinding, the grinding time may be 1-3 hours.

Mixing:

Using a pin mixer in the preconditioning stage of pelletized lime production offers several benefits, including improved material consistency, reduced binder requirements, and increased production efficiency. The pin mixer ensures even distribution of moisture and binder, creating a more uniform feed for pelletizing, which results in stronger, more durable pellets. It also reduces the amount of binder needed and minimizes dust generation, lowering production costs and material waste. Additionally, the enhanced preconditioning leads to higher throughput and more stable pellet formation, improving overall process control and product quality.

3. Calcination

The selected limestone is crushed into blocks of 5-30 cm in size and sent to high-temperature calcination equipment such as vertical kilns and rotary kilns. At high temperatures of 1000-1200℃, limestone undergoes a decomposition reaction: CaCO₃→CaO + CO₂↑. Taking a maelz rotary kiln with a daily output of 500 tons as an example, the temperature in the kiln needs to be precisely controlled at around 1150℃. By adjusting the input amount of fuel (such as natural gas, coal powder) and the amount of combustion air, the limestone is fully decomposed to generate calcium oxide (CaO), that is, quicklime.

4. Quicklime digestion

The calcined quicklime needs to be digested and reacted with an appropriate amount of water to generate calcium hydroxide (Ca (OH)₂). The reaction formula is: CaO + H₂O→Ca (OH)₂. In this process, the ratio of water to lime is very critical, usually 1: (2-3). In order to ensure sufficient reaction, special digestion equipment is often used, such as a continuous digester, that we can fully mix quicklime and water, and the digestion time is controlled at 15-30 minutes to convert quicklime into a fine slaked lime slurry.

5. Granulation

The slaked lime slurry is dehydrated and dried to reduce its water content to 10% - 15%, and then granulated by disc granulator, roller extrusion granulator and other equipment. When the disc granulator is working, the speed is generally controlled at 15 - 30 rpm, and the slaked lime material keeps rolling and agglomerating in the rotating disc to form particles with a particle size of 1 - 5 mm. The roller extrusion granulator squeezes the slaked lime material into regular particles through two rollers with specific grooves that rotate relative to each other. The particles are stronger and easier to store and transport.

Screening and packaging

The lime pellets is screened by equipment such as vibrating screens to remove oversized or undersized particles that do not meet the particle size requirements to ensure uniform product particle size. Qualified products are packaged by automatic packaging equipment. Common packaging specifications include 25 kg/bag, 50 kg/bag, etc. The packaged granulated lime can be stored and transported to agricultural, industrial and other application fields.

Types of lime

Agricultural Lime (Aglime)

Agricultural lime (Aglime) is a soil conditioner widely used in agriculture. Its main component is calcium carbonate (CaCO₃), and it may also contain a small amount of magnesium carbonate (MgCO₃). There are two main types of agricultural lime, depending on the source and processing method. One is limestone powder made from natural limestone through crushing and grinding, which is the most common type; the other is dolomite lime processed from dolomite (a carbonate ore containing magnesium), which not only contains calcium but also provides magnesium to the soil. Agricultural lime can effectively adjust the pH value of the soil. Generally, applying 1-2 tons of agricultural lime per hectare of acidic soil can increase the soil pH value by 0.5-1.0 units, thereby improving the acidic soil environment and reducing the toxic effects of elements such as aluminum and manganese on crops. At the same time, it can also provide nutrients such as calcium and magnesium required for plant growth, enhance the soil's ability to retain fertilizer and water, and promote the activity and reproduction of soil microorganisms. For example, in the soil after the application of agricultural lime, the number of beneficial microorganisms can increase by 20% - 30%, thereby improving soil fertility, helping crop growth and increasing yields.

Pelletized Lime

Granular lime is made by calcining limestone at a high temperature of 1000-1200℃ to decompose it to produce calcium oxide. Then the calcium oxide is digested with an appropriate amount of water to produce calcium hydroxide. Finally, the calcium hydroxide is made into granules through special granulation equipment, such as a disc granulator or a roller extrusion granulator, and after drying, screening and other processes, the final granular lime product is obtained. Its particle size is mostly 1-5 mm, the particle size is uniform, it has good fluidity, is easy to store and transport, and the storage period is about 50% longer than that of powdered lime. It has a high neutralization value and can effectively adjust the pH of the soil.

Powdered Lime

Powdered Lime is a white powdery substance made from limestone and other raw materials through high-temperature calcination and grinding. Its main component is calcium oxide (CaO), which usually contains more than 90%. Lime powder is highly alkaline, with a pH value of 12-13. Its particle size is usually between 100-325 mesh and has a large specific surface area, which allows it to react quickly when in contact with water or other substances.

Dolomitic Lime

Dolomite lime is made from high-purity dolomite ore (calcium and magnesium carbonate content exceeds 90%, and high-quality ore can reach 95%), which is crushed, calcined and decomposed in a high-temperature kiln at 900-1000℃, and then ground into products of different finenesses. Its main component, calcium and magnesium carbonate, decomposes into magnesium oxide (18%-22%) and calcium oxide (30%-40%). It is highly alkaline, with a pH value of 9-11, and slightly poor solubility in water. In agriculture, it can raise the pH value of acidic tea gardens in the south from 4-5 to 5.5-6.5, help the growth of tea trees, and also bring many quality improvements to apple orchard fruits; in industry, it is a key raw material for steel slag-making agents, glass fluxing and clarification agents, and refractory materials. However, excessive application will affect soil plants and water quality

Hydraulic Lime

Hydraulic lime is a lime material with hydraulic properties. The main component of hydraulic lime is calcium oxide (CaO), and it also contains a certain amount of active silicate (SiO₂), aluminum oxide (Al₂O₃) and other components. The uniqueness of hydraulic lime lies in its hydraulic properties. Unlike ordinary lime (air-hardening lime), hydraulic lime can not only harden in the air, but also continue to harden in water and maintain and develop its strength. This is because the active ingredients in hydraulic lime will undergo a series of complex hydration reactions after contacting water, generating hydration products with gelling properties, such as calcium silicate, calcium aluminate, etc. These hydration products can form a solid structure in water, thus giving the lime good water resistance and strength.

Hydrated Lime (Ca(OH)₂) - Slaked Lime

Hydrated Lime is a white powdery solid with slight hygroscopicity. Its density is about 2.24 g/cm³. It is usually made by reacting quicklime (calcium oxide, CaO) with water, a process called lime slaking or slaking. The reaction equation is CaO + H₂O = Ca (OH)₂. This reaction is an exothermic reaction, which releases a large amount of heat and raises the temperature of the reaction system. In industrial production, in order to ensure that the reaction proceeds fully, quicklime is usually added to excess water to make lime milk, which is then precipitated, filtered, dried and other processes to obtain slaked lime products.

Quicklime (CaO) - Calcium Oxide

Quicklime (CaO) is calcium oxide, which is a white or off-white block or powder solid with a density of 3.3-3.4 g/cm3, a melting point of 2572℃, a boiling point of 2850℃, strong hygroscopicity, alkalinity, and active reaction with water, acid, and acidic oxides. It is made of limestone with more than 90% calcium carbonate (high quality up to 95%-99%), which is crushed to 5-30 cm and calcined at 900-1200℃ for 8-12 hours. In industry, it is a key raw material for steel slag making, chemical product manufacturing, and papermaking waste liquid treatment.

Building Lime

Building lime is a lime material used in the construction industry. Its main components are calcium oxide (CaO) and calcium hydroxide (Ca (OH)₂). It is made from limestone and other raw materials through high-temperature calcination and digestion processes. After adding water, a hydration reaction will occur to generate calcium hydroxide, which has a certain viscosity and can cement sand, stone and other materials together to form a structure with a certain strength, making the building structure more stable. After adding water and stirring, building lime can form a lime slurry with good plasticity, which is convenient for construction workers to carry out operations such as smearing, masonry, and painting. It can fill the gaps between building materials and make the building surface smooth and flat.

Air Lime (Non-Hydraulic Lime)

Soda Lime

Soda lime, also known as sodium lime, is a white or beige powder with a slightly pungent odor. It contains calcium oxide, sodium hydroxide, potassium hydroxide, etc. Sodium hydroxide and potassium hydroxide are easily soluble in water, and calcium oxide can react with water. Its chemical properties are strongly alkaline and can neutralize with acids; it is extremely hygroscopic, sodium hydroxide and potassium hydroxide will deliquesce, and calcium oxide also participates in moisture absorption, so it is often used as a desiccant; it can also react with acidic gases such as carbon dioxide and sulfur dioxide, and is used to absorb acidic gases. Based on these characteristics, soda lime is widely used as a desiccant, carbon dioxide absorber and alkaline catalyst in laboratories and industrial production.

Dead Burnt Lime

Dead burnt lime is made by calcining limestone at extremely high temperatures (about 1800-2000℃). It is characterized by extremely high calcium oxide (CaO) content, usually more than 95%, dense structure and extremely low reactivity. Due to this low activity, it is used in industry for occasions that require high temperature resistance and chemical corrosion resistance. For example, in the production of refractory materials, it can significantly improve the high temperature stability of refractory bricks. The refractory bricks made from it can withstand high temperatures above 1600℃ without softening and deformation.

Chemical Lime

Chemical lime is a high-purity lime used in chemical industry production. Its calcium oxide content is generally 85% - 98%, and the impurity content is strictly controlled according to different application scenarios. In chemical synthesis, such as the production of calcium carbide (CaC₂), the calcium oxide content of chemical lime is required to be at least 90% to ensure sufficient reaction with coke and increase the yield and purity of calcium carbide. It can accurately participate in various chemical reactions. For example, in the manufacture of soda ash, it is an indispensable raw material to promote the efficient operation of related chemical processes.

Bio Lime

Bio Lime is derived from calcium carbonate raw materials of biological origin such as natural shells and corals, and is made by calcining at low temperature (about 700-900℃). Compared with ordinary lime, it contains a small amount of biological trace elements, such as magnesium, iron, zinc, etc., with a total amount of about 0.5%-2%. It is widely used in agriculture and horticulture. When used for soil improvement, it can not only adjust the soil pH value and increase the pH value of acidic soil by 0.5-1.5 units, but also provide unique nutrients for soil microorganisms, promote the reproduction of beneficial microorganisms, and enhance soil fertility and ecological vitality.

Carbonate Limes

The main component of carbonate lime is calcium carbonate (CaCO₃), with a purity of 70% - 95%. It has a variety of appearances, ranging from white to gray. Common marble and chalk belong to this category. In the construction industry, it is widely used as a natural stone for wall decoration, sculpture, etc., because of its moderate hardness, Mohs hardness of about 3 - 4, and easy to process and carve. In industry, it can be used as a slow release agent of carbon dioxide, decomposing at a specific temperature (about 825℃) to produce carbon dioxide, which is used in food processing, chemical foaming and other processes.

Refractory Lime

Refractory lime is made of high-purity limestone and calcined at 1600-1800℃. The calcium oxide content exceeds 92% and there are very few impurities. It has excellent high temperature resistance, the load softening temperature can reach above 1650℃, and it has good thermal shock resistance. In high-temperature industries such as metallurgy and glass, it is used to make refractory bricks, furnace linings, etc. It can withstand high-temperature melt erosion, ensure the stable operation of the furnace, significantly extend the service life of the equipment, and reduce the maintenance cost of industrial production.

Metallurgical Lime

Metallurgical lime is a key auxiliary material for steel and nonferrous metal smelting. It has a high calcium oxide content, generally 85% - 95%, and a large proportion of effective calcium oxide (the part that can quickly participate in metallurgical reactions). In converter steelmaking, about 50 - 100 kg of metallurgical lime is required per ton of steel, which is used for slag making, quickly removing impurities such as sulfur and phosphorus from molten steel, improving the purity and quality of steel, and reducing the sulfur content to below 0.03% and the phosphorus content to below 0.04%.

Paper Mill Lime

Paper Mill Lime is mainly used in the causticizing process to convert sodium carbonate into sodium hydroxide and recycle papermaking chemicals. Its calcium oxide content is usually 80% - 90%, and impurities (such as heavy metals) are strictly controlled. In the papermaking process, about 20-50 kg of lime is required for each ton of pulp production, which can reduce production costs. At the same time, in the pulp bleaching process, the pH value is adjusted to 9-11 to optimize the bleaching effect and improve the paper whiteness, which can increase the paper whiteness by 10-20 degrees.

Sugar Refining Lime

Sugar refining lime is used in the sugar cane or beet sugar making process to remove impurities and pigments in the sugar juice. Its calcium oxide content is about 85% - 92%, preferably in fine powder form. When clarifying sugar juice, 0.5 - 2 kg of lime is added per ton of sugar juice. It reacts with the acidic substances in the sugar juice to form a precipitate, effectively separates impurities, improves the purity of the sugar juice, and increases the sucrose extraction rate by 2% - 5%, ensuring the quality of the final sugar product.

Petroleum Lime

Petroleum lime is used in the petroleum refining process, such as desulfurization and deacidification. Its calcium oxide content is generally 80% - 90%, and it is highly active. In the desulfurization of petroleum products, it can react with mercaptans, hydrogen sulfide, etc. in the oil products to reduce the sulfur content of the oil products and meet environmental protection standards. For example, in diesel desulfurization, the sulfur content can be reduced from 500ppm to below 10ppm, improving the quality of diesel and reducing exhaust pollutant emissions.

Fluoride Lime

Fluoride lime usually refers to lime products containing a certain amount of calcium fluoride (CaF₂), with a calcium fluoride content of 10% - 30%. It has fluxing properties and can reduce the melting point of materials in smelting or chemical processes. In the aluminum electrolysis industry, adding fluoride lime can reduce the melting point of the electrolyte by about 50 - 100℃, reduce energy consumption, improve aluminum production efficiency, and reduce electricity consumption per ton of aluminum by 100 - 200 degrees.

Phosphatic Lime

The main component of phosphatic lime is calcium phosphate (Ca₃(PO₄)₂), and the phosphorus (P₂O₅) content is 18% - 30%. It is an important raw material for phosphate fertilizer. It is difficult to dissolve in water, but it can slowly release phosphorus in the soil through the action of microorganisms and acidic substances, providing long-term phosphorus nutrition for plants. In agricultural fertilization, applying 1000-2000 kg of phosphatic lime per hectare can significantly increase crop yields, increase wheat yields by about 10% - 15%, and improve the quality of agricultural products.

Magnesium Lime

Magnesium lime is made by calcining magnesium-containing raw materials such as dolomite (CaMg (CO₃)₂), with a magnesium oxide (MgO) content of 15% - 35% and a calcium oxide content of 30% - 50%. It can both regulate soil pH and supplement soil magnesium. In magnesium-deficient soils, applying 500-1000 kg of magnesium lime per hectare can increase the soil pH by 0.3-0.8 units. It can also effectively alleviate the symptoms of magnesium deficiency in plants, enhance photosynthesis, improve crop resistance, promote fruit enlargement and sugar accumulation, and increase the sweetness of fruits by 1-2 degrees.

What are the Benefits of Using Pelletized Lime?

Enhancing Soil Structure and Fertility

Improved Nutrient Availability

• Pelletizing lime can effectively regulate soil pH. Most plants grow best in soils with a pH of 6.0 - 7.5. Acidic soils increase the solubility of elements such as aluminum and manganese, which are toxic to plants, and inhibit the effectiveness of macroelements such as phosphorus, potassium, calcium, magnesium, and trace elements such as iron, zinc, and copper. For example, when the soil pH is 4.5, the effectiveness of phosphorus is extremely low. After applying granular lime, the soil pH can be increased to about 6.5, which significantly improves the effectiveness of phosphorus and increases the amount of phosphorus in the soil that can be absorbed by plants by about 3 - 5 times.
• Ion exchange: The calcium ions (Ca²⁺) in granular lime can exchange with other cations in the soil. The surface of soil colloids usually has a negative charge and will adsorb various cations, such as hydrogen ions (H⁺), aluminum ions (Al³⁺), iron ions (Fe³⁺), etc. When granular lime is applied, calcium ions will replace acidic ions such as hydrogen ions adsorbed on soil colloids, making the soil less acidic. At the same time, this ion exchange also helps to release nutrient ions such as potassium ions (K⁺) and magnesium ions (Mg²⁺) adsorbed by soil colloids, making them easier for plants to absorb and utilize. Studies have shown that within one month after the application of granular lime, the content of exchangeable potassium and magnesium ions in the soil can increase by 10% - 20% and 15% - 25% respectively.

Promotion of Beneficial Microbial Activity

• Provide a suitable environment: Beneficial microorganisms such as rhizobia, actinomycetes, mycorrhizal fungi, etc. grow and reproduce well in a neutral to slightly alkaline environment. Granular lime adjusts the soil pH value to a suitable range, creating favorable living conditions for these microorganisms. For example, rhizobia have the strongest nitrogen-fixing activity in an environment with a pH value of 6.5-7.5. After applying granular lime, the number of rhizobia in the soil can increase by 2-3 times within two months, thereby enhancing the soil's nitrogen-fixing ability and providing more nitrogen nutrition for plants.
• Promote microbial metabolism: The calcium element in granular lime is an important component of the cell structure and enzyme system of many microorganisms. It can participate in the synthesis of microbial cell walls, enhance cell stability, and act as an activator of certain enzymes to promote microbial metabolic activities. For example, calcium can activate the activity of phosphatase in the soil, allowing organic phosphorus compounds to decompose faster into inorganic phosphorus for plant absorption. Studies have found that in soils with granular lime added, the activity of phosphatase can be increased by 30%-50%, accelerating the decomposition of organic matter and nutrient circulation in the soil, and further promoting the growth and reproduction of beneficial microorganisms.

Advantages Over Traditional Agricultural AGLime

1. Ease of Application

Precision fertilization:

Pelletized lime usually has a relatively uniform particle size and shape, which allows for more precise control of the amount of application during fertilization. For example, ordinary agricultural lime may have different particle sizes, making it difficult to accurately grasp the amount of application per square meter or per acre of land during fertilization, while granular lime can be evenly spread according to a pre-set amount through precise metering equipment such as a seeder or fertilizer applicator. Generally speaking, the error of fertilizer application can be controlled within ±5% using granular lime, compared to the error of ordinary agricultural lime, which may reach about ±15%.

Effort-saving and efficient:

Lime pelleting has larger particles and a relatively hard texture, and is not easy to break and clump during transportation and application. This makes farmers or agricultural workers more labor-saving when operating and can improve the efficiency of fertilization. For example, in large areas of farmland, using granular lime for fertilization, a small fertilizer applicator can complete the fertilization work of 10-15 acres of land per day, while using ordinary agricultural lime, due to its easy agglomeration and poor fluidity, the same fertilizer applicator may only complete the fertilization task of 6-10 acres of land per day.

2. Faster Soil Integration

Larger reaction area:

Pell lime undergoes special processing during the production process, and its particle surface is relatively rough, with a larger specific surface area. This means that when in contact with the soil, it can provide more reaction sites and accelerate the neutralization reaction between lime and acidic substances in the soil. Studies have shown that the contact area between granular lime and soil is 20% - 30% larger than that of ordinary agricultural lime, which makes the neutralization reaction faster. For example, in acidic soil, after applying granular lime, the pH value of the soil can be increased by 0.5 - 1.0 units within a week, while the application of ordinary agricultural lime may take two weeks or more to achieve the same effect.

Good water permeability and air permeability:

There are certain pores between the particles of lime pellets, which are conducive to the circulation of water and air in the soil. When granular lime is applied to the soil, it can quickly improve the structure of the soil and increase the water permeability and air permeability of the soil. This helps the microbial activity in the soil and the growth of plant roots, further promoting the integration of lime and soil. For example, soil porosity can be increased by 10% - 15% after granular lime is applied, allowing plant roots to better absorb water and nutrients, improving plant growth rate and stress resistance.

3. Reduced Dust and Improved Handling

Reduce dust pollution:

Ordinary agricultural AGlime is usually in powder or fine particles, which easily generates a lot of dust during handling, storage and application. These dusts not only pollute the environment, but also harm the health of operators. Lime pellets are not easy to generate dust due to their large particles. For example, under the same operating conditions, when ordinary agricultural lime is used, the dust concentration in the surrounding air may reach 10-20 mg/m3, while when granular lime is used, the dust concentration can be reduced to 1-3 mg/m3, which greatly improves the working environment.

Easy to store and transport:

Pelletized lime has large particles and regular shapes, which are not easy to leak and scatter during storage and transportation. They can be easily bagged, stacked and handled, reducing the risk of packaging damage and material loss. For example, the breakage rate of pelletized lime bags during storage and transportation is usually less than 5%, while the breakage rate of ordinary agricultural lime bags may be as high as 15%-20%. In addition, granular lime is not easily affected by moisture and agglomerates during storage, and can maintain good fluidity and stability, which is conducive to long-term storage and ready use.

Why is Pelletized Lime Better than Non-Pelletized Alternatives?

1. Convenience of application

• Accurate dosage control: Lime has a regular shape and particle size, and is precisely measured. The ability of lime to effectively change soil conditioning is directly related to the particle size of the product used and the quality of the limestone. Smaller particles can increase the total risk of contact with soil acidity, thereby increasing soil pH and improving the neutralization of the effects required for soil conditioning. In agricultural soil improvement, key particles are used accurately. For example, studies have shown that the use of granular lime can control the application amount within ±5%, except for granular lime (such as powder) which is easy to float and agglomerate, the application amount is close to ±15% - 20%. This precision ensures that the soil pH adjustment is more consistent, and it is expected to avoid the impact of excessive or insufficient lime on soil ecology and crop growth.
• Mechanized operation expectations: Granular lime has good fluidity and is suitable for various types of mechanized fertilization equipment, such as seeders, fertilizer spreaders, etc. In large-scale farmland operations, mechanized granular lime can cover 5-10% of the field. In contrast, non-granular lime, especially the sticky paste lime, is difficult to spread evenly by machinery, and manual spreading is slow, which can only cover 0.2-0.5% of the field, and the labor intensity is high. Although powdered lime has smaller particles, it is difficult to apply accurately due to operational difficulties, and it is very easy to spread to unwanted areas, resulting in messy, poor and ineffective results.

2. Storage and transportation advantages

2.1 Reduce the risk of agglomeration:

Non-pelletized lime, especially powdered lime, is very easy to agglomerate during storage due to absorption of moisture in the air. According to statistics, in an environment with a humidity of 60%-70%, the agglomeration rate of powdered lime can reach 30%-40% after being stored for 1 month, which seriously affects subsequent use. Granular lime has a small contact area between particles and has better moisture resistance after granulation. After being stored for 6 months under the same humidity environment, the agglomeration rate is only 5%-10%, which greatly extends the storage period and reduces inventory management costs.

2.2 Reduce transportation losses:

Pellet lime is not easy to break into fine powder during bumpy transportation due to its high particle strength, which reduces the loss caused by dust flying. Taking long-distance road transportation as an example, the transportation loss rate of non-granular lime is usually 8%-12%, while the loss rate of granular lime can be controlled at 3%-5%. This not only reduces transportation costs, but also reduces pollution to the transportation environment.

3. Effects and Duration

• Reaction rate and durability: The smaller the lime particles, the faster the decomposition and neutralization effect compared to other forms of lime. However, although the initial reaction rate of granular lime with soil is slightly slower than that of powdered lime, the reaction is more durable due to its particle structure. In acidic soil improvement, powdered lime can quickly increase the soil pH in a short period of time after application, but the effect is short-lived and the soil pH may fall back after 3-4 months. For commonly used lime improvers in agriculture, agricultural lime is inconsistent in size and has coarse particles. It usually takes 3-5 years to decompose, which makes the effect difficult to predict and delays the time for crops to reach optimal yields. Granular lime can slowly release active ingredients in the soil, so that the soil pH value remains stable for 6-8 months, and the soil pH is maintained for a long time.
• Reduce soil disturbance: Non-granular lime, especially liquid or paste lime, will change the original soil structure after application, causing local soil to be too wet or too dry, affecting soil permeability and microbial activity. Pelletized lime, when applied, can gradually work without destroying the soil structure, maintaining good physical properties of the soil, creating a stable living environment for soil microorganisms, promoting soil ecological balance, and improving soil fertility. Pelleting lime also provides many other benefits, such as increased nutrient absorption, improved water retention, plant root growth, reduced soil erosion, reduced the chance of soil crust formation, and maintained soil aggregate structure. Quicklime and hydrated lime, while fast-acting, can cause damage to plants and, as mentioned earlier, are also harmful to people who come into contact with them. Granular lime is the best choice for agricultural operations. All lime products can improve soil conditions, but granular lime is the fastest, most stable, and most effective in raising soil pH. Even better, granular lime retains the advantage of small particles because the particles break down easily. The uniform particle size also allows for precise application and predictable neutralization effects. In addition, because limestone particles are easy to transport and apply, they avoid the operational difficulties associated with powdered lime, quicklime, and hydrated lime.

What are the Applications of Pelletized Lime?

Agricultural Uses

Crop Yield Improvement

• Adjust soil pH: Many crops grow best in neutral to slightly acidic soils. In acidic soils, excess hydrogen ions inhibit the absorption of nutrients by plant roots and may also increase the solubility of elements such as aluminum and manganese, which can be toxic to plants. When pelletized lime is applied to the soil, the calcium oxide (CaO) or calcium hydroxide (Ca (OH)₂) in it reacts with hydrogen ions in the soil to neutralize and increase the soil pH. For example, in tea gardens in the south, the soil pH is often lower than 5, which can easily affect the growth of tea trees. After applying granular lime, the soil pH can be raised to 5.5-6.5, creating a more suitable growth environment for tea tree roots and promoting the absorption of nutrients such as nitrogen, phosphorus, and potassium by the roots, thereby increasing tea yield. Studies have shown that tea yield can be increased by 10%-20% after the proper application of granular lime.
• Improve soil structure: Pellet lime can promote the formation of aggregate structure of soil particles. On the one hand, calcium ions exchange with sodium ions on the surface of soil colloids, causing soil particles to condense with each other; on the other hand, lime increases the soil pH value, promoting the activity of microorganisms in the soil, and sticky substances such as polysaccharides secreted by microorganisms also help soil particles to agglomerate. A good soil aggregate structure can enhance the air permeability and water retention of the soil. Taking corn planting as an example, applying pelleting lime to heavy clay soil can improve the soil structure, so that the corn root system can stretch better, take root deeper, absorb more nutrients and water, and the corn yield can increase by 15% - 25%.
• Enhance plant stress resistance: Granular lime indirectly enhances plant stress resistance by regulating the soil environment. Appropriate soil pH and structure are conducive to the healthy growth of plants, and enhance their resistance to adversities such as pests and diseases, drought, and low temperature. For example, in vegetable cultivation, after using granular lime to improve the soil, the vegetable plants grow vigorously and have thick leaves. The infection rate of common diseases such as downy mildew and powdery mildew is reduced by 20% - 30%. Even when encountering short-term droughts, they can maintain a good growth state and ensure stable vegetable yields.

Integration with Fertilization Practices

• Improve fertilizer utilization: The effectiveness of fertilizers is closely related to soil pH. In acidic soils, phosphate fertilizers are easily combined with elements such as iron and aluminum to form insoluble compounds, which reduces the effectiveness of phosphorus. Granular lime can reduce the fixation of phosphate fertilizers and improve their effectiveness after increasing soil pH. For example, in rice fields, the effective phosphorus content in the soil can be increased by 20% - 30% by applying granular lime in combination with phosphate fertilizers. At the same time, for ammonium nitrogen fertilizers, under a suitable pH environment, ammonium ions (NH₄⁺) are not easily converted into ammonia (NH₃) and volatilized, which improves the utilization rate of nitrogen fertilizers. Studies have shown that the reasonable combination of granular lime and nitrogen fertilizers can increase the utilization rate of nitrogen fertilizers by 10% - 15%, reduce fertilizer waste, and reduce production costs.
• Optimize fertilization plans: Granular lime can be scientifically matched with different types of fertilizers according to soil test results and crop needs. When planting crops that require a large amount of calcium (such as peanuts) in acidic soil, adding granular lime to the base fertilizer and combining it with nitrogen, phosphorus and potassium compound fertilizers can not only meet the peanut's demand for calcium and promote pod development, but also provide comprehensive nutrients for plant growth. In the topdressing stage, adjust the application amount of granular lime and other fertilizers according to the soil pH value and crop growth conditions. For example, in the early stage of crop growth, apply granular lime in an appropriate amount to improve the soil environment and promote root growth. In the later stage, according to the growth trend of crops, apply high nitrogen or high potassium fertilizers to achieve precise fertilization and improve crop yield and quality.
• Promote the synergistic effect of microorganisms and fertilizers: Granular lime adjusts the soil pH value and creates a suitable living environment for soil microorganisms. Beneficial microorganisms such as nitrogen-fixing bacteria and phosphate-solubilizing bacteria are more active at appropriate pH values. Nitrogen-fixing bacteria can convert nitrogen in the air into nitrogen that can be used by plants, and phosphate-solubilizing bacteria can decompose insoluble phosphorus in the soil into effective phosphorus. When combined with fertilizers, microbial activity is enhanced, which can accelerate the decomposition and conversion of fertilizers and make them easier for plants to absorb. For example, in orchards, after applying granular lime, the number of microorganisms in the soil increases by 30% - 50%. Combined with the application of organic fertilizer, the decomposition rate of organic fertilizer is accelerated, providing a continuous nutrient supply for fruit trees, and the fruit quality and yield are improved.

Lawn and Garden Care

Correcting Lawn Soil Acidity

• Principles and advantages: Lawn soil tends to be acidic due to frequent watering, fertilization, and natural precipitation leaching. Pelletized lime is mainly composed of calcium oxide (CaO) and calcium hydroxide (Ca (OH)₂). After being applied to acidic lawn soil, it can react with hydrogen ions in the soil to neutralize. For example, calcium hydroxide reacts with hydrogen ions: Ca (OH)₂ + 2H⁺ → Ca²⁺ + 2H₂O, thereby increasing the soil pH. Compared with powdered lime, granular lime is less likely to produce dust pollution during transportation and application, and the particles are uniform, which is convenient for precise control of the application amount. Generally speaking, for every 100 square meters of lawn with strong acidity (pH 4.5 - 5.5), it is recommended to apply 10 - 15 kg of granular lime, which can gradually increase the soil pH to the range of 6.0 - 7.0 suitable for lawn grass growth.
• Long-term effect: Continuous use of lime pellet to correct soil acidity can stabilize soil pH and prevent the soil from increasing the solubility of aluminum, iron and other elements due to long-term acidic environment, which will cause poisoning to the roots of lawn grass. At the same time, it helps to improve the soil aggregate structure, enhance the soil's ability to retain fertilizer and water, create a good soil environment foundation for the growth of lawn grass, and reduce problems such as yellow leaves and slow growth of lawn grass due to soil discomfort.

Promoting Healthy Grass Growth

• Nutrient synergy: In addition to regulating soil pH, lime pelleting can also provide calcium for lawn grass growth. Calcium is an important component of plant cell walls, which can enhance the stability and strength of cell walls, make lawn grass stems tougher, and improve lodging resistance. In some calcium-deficient lawn soils, after applying granular lime, the absorption efficiency of lawn grass roots for major nutrients such as nitrogen, phosphorus, and potassium can be increased by 15% - 20%. For example, an appropriate amount of calcium can promote the absorption and conversion of nitrogen by the roots, help lawn grass leaves to be dark green and grow vigorously, and improve the overall ornamental value of the lawn.
• Microbial assistance: A suitable soil pH value is a key condition for the activity of soil microorganisms. After pell lime adjusts soil acidity, it is conducive to the reproduction and growth of beneficial microorganisms such as nitrogen-fixing bacteria and nitrifying bacteria in the soil. Nitrogen-fixing bacteria can convert nitrogen in the air into nitrogen that can be absorbed by lawn grass, while nitrifying bacteria participate in the nitrogen cycle and improve the effectiveness of soil nitrogen. Studies have shown that the number of nitrogen-fixing bacteria in lawn soil can increase by 3-5 times after the pH value is adjusted by applying granular lime, which promotes the healthy growth of lawn grass and reduces the use of chemical fertilizers.

Environmental and Industrial Applications

• Environmental remediation: In some areas affected by industrial pollution or acid rain, soil and water acidification is serious, destroying the local ecological balance. Pelletized lime can be used for large-scale environmental remediation projects. For example, in abandoned mines, due to ore mining and acid wastewater discharge, the soil pH value is often as low as 4 or below, making it difficult for vegetation to grow. By spreading granular lime, the application amount can reach 5-10 tons per hectare, gradually improving soil acidity and creating conditions for vegetation recovery. In terms of water body remediation, for acidic lakes or rivers, granular lime can be placed in a special slow-release device to slowly release alkaline substances, adjust the pH value of the water body, and protect the living environment of aquatic organisms.
• Industrial waste gas treatment: In industrial production, such as steel, chemical and other industries, a large amount of waste gas containing acidic gases such as sulfur dioxide (SO₂) will be generated. Pelletized lime can be used for waste gas desulfurization treatment. limestone pellets is made into lime slurry and fully contacted with waste gas. Sulfur dioxide reacts with calcium hydroxide in lime slurry: Ca (OH)₂ + SO₂ → CaSO₃ + H₂O to generate calcium sulfite precipitation, thereby removing sulfur dioxide from waste gas, reducing acid rain formation, and reducing environmental harm. The desulfurization efficiency can reach more than 90%.

Water Treatment

• Adjusting pH value: In drinking water treatment, the pH value of raw water may vary greatly depending on the water source. If the pH value is too low, it will corrode the water pipeline, affecting water quality and water supply safety. Pelletized limestone can be used to adjust the pH value of raw water. Pellets is dissolved in water to prepare lime milk, which is slowly added to the raw water. By accurately controlling the dosage, the pH value of the raw water can be adjusted to the appropriate range of 6.5-8.5. In sewage treatment, some industrial wastewater and domestic sewage are acidic and need to be neutralized before discharge. Granular lime has low cost and stable treatment effect. It can effectively neutralize the acidic substances in the wastewater so that the treated wastewater meets the discharge standard.
• Removing impurities: The calcium ions produced by the dissolution of Pellet lime in water can combine with carbonate ions, phosphate ions, etc. in the water to form precipitations such as calcium carbonate and calcium phosphate, thereby removing these impurities in the water and reducing the hardness of the water. For example, in some areas with high groundwater hardness, the calcium and magnesium ion content in the water can be reduced by 30% - 50% after treatment with pelle lime, reducing scale formation, improving water quality, and ensuring the normal operation of water-using equipment.

Waste Management

• Sludge treatment: The sludge produced in urban sewage treatment plants contains a large amount of organic matter and heavy metals. limestone pelletized can be used for sludge stabilization treatment. When pellet lime is mixed with sludge, on the one hand, the alkalinity of lime can inhibit the growth of harmful microorganisms in the sludge and reduce the generation of odorous gases; on the other hand, lime reacts with water in the sludge to generate heat, promote the decomposition of organic matter in the sludge, and at the same time increase the pH value of the sludge, so that heavy metals form hydroxide precipitation, reduce the biological effectiveness of heavy metals, and reduce the risk of secondary pollution. Generally, adding 50-100 kg of granular lime per cubic meter of sludge can effectively improve the properties of sludge and facilitate subsequent sludge disposal and resource utilization.
• Neutralization of acidic waste: Various types of acidic wastes are generated in industrial production, such as waste acid liquid, acidic waste residue, etc. Pelletized lime can be used to neutralize these acidic wastes. Taking waste acid liquid treatment as an example, granular lime is slowly added to the waste acid liquid to produce a neutralization reaction, consume hydrogen ions in the waste acid, and reduce the acidity. This treatment method is relatively low in cost, and most of the reaction products, such as calcium salts, can be further processed to achieve resource utilization, reduce the harm of acidic waste to the environment, and achieve harmless and reduced waste treatment.

How to Apply Pelletized Lime Effectively

1. Assessing Soil Needs

Soil type considerations:

Different soil types have different requirements for lime. Clay soils have strong fertility and water retention capabilities, but poor air permeability and are usually highly acidic because the clay mineral structure easily absorbs a large number of hydrogen ions. For example, clay soils, which are common in temperate regions, have a cation exchange capacity (CEC) of 20 - 40 cmol (+)/kg, which means that more lime is needed to neutralize the acidity and adjust the soil structure. In contrast, sandy soils have a CEC of only 5 - 15 cmol (+)/kg. Although the acidity is relatively low, it has weak fertility and water retention. When applying lime, you need to pay attention to the amount used to avoid excessively raising the soil pH and affecting the effectiveness of soil nutrients.

Analysis of vegetation growth:

Observing vegetation growth can intuitively reflect soil needs. If the leaves of plants turn yellow, grow slowly and are short, it may be that the soil is too acidic, causing elements such as iron and aluminum to poison the roots and hinder nutrient absorption. At this time, lime needs to be applied to adjust the pH value. For example, in a blueberry plantation, if blueberry leaves show chlorosis, it is likely that the soil pH is higher than its suitable range (4.0 - 5.5), and the amount of lime application needs to be increased to reduce soil acidity and restore healthy plant growth.

Research on historical fertilization and tillage records:

Soils that have been applied with large amounts of acidic fertilizers (such as ammonium sulfate) for a long time are prone to acidification and require more lime to neutralize. For example, in farmland where vegetables have been grown for many consecutive years and nitrogen fertilizers have been applied in large quantities, the soil pH may drop below 5.5, and the amount of lime application should be appropriately increased. In addition, frequent deep plowing will destroy the soil aggregate structure and reduce the soil buffering performance, and lime needs to be reasonably supplemented to maintain the soil acid-base balance.

2. Conducting Soil Tests

Sampling depth and breadth:

To obtain accurate soil data, the sampling depth is generally 0-20 cm, which is the main distribution layer of plant roots. For large areas of farmland, set a sampling point every 10-15 mu in an "S" shape or chessboard layout to ensure that the collected soil can represent the entire area. For example, in a 100-mu corn field, at least 7-10 sampling points need to be set up, and the soil collected at each point is mixed evenly to make a representative soil sample.

Sampling tool selection:

Use a stainless steel soil drill or soil shovel to collect soil to avoid the tool material affecting the soil composition. The soil drill can accurately collect columnar soil samples and is suitable for deep soil sampling; the soil shovel is convenient for quickly collecting samples in the surface soil. When sampling, the amount of soil taken at each sampling point should be consistent, about 200-300 grams, to ensure the representativeness of the mixed soil sample.

Test item determination:

Conventional soil test items include pH value, organic matter content, cation exchange capacity (CEC), and nutrient content such as nitrogen, phosphorus, and potassium. The pH value directly reflects the soil acidity and alkalinity and is a key indicator for determining the amount of lime to be applied. The organic matter content affects the soil's ability to retain fertilizer and water and its buffering properties. Generally, the ideal organic matter content of cultivated land soil should be between 2% and 4%. CEC determines the soil's ability to adsorb and exchange nutrient ions. The higher the value, the stronger the soil's ability to retain fertilizer. By comprehensively analyzing these items, we can fully understand the soil conditions and provide a scientific basis for the rational application of lime.

3. Interpreting Soil Test Results

PH Interpretation:

Soil pH is an important indicator of soil acidity and alkalinity. For most crops, the appropriate pH range is 6.0 - 7.5. If the test results show that the pH is lower than 6.0, it indicates that the soil is too acidic and lime needs to be applied to increase the pH. For example, when the pH is 5.5, about 1 - 2 tons of granular lime should be applied per acre to gradually restore the soil pH to the appropriate range. If the pH is higher than 7.5, the soil is alkaline, and there may be too many alkaline ions such as sodium and calcium. At this time, lime should be applied with caution, and other improvement measures such as irrigation and drainage can be adopted first.

Cation Exchange Capacity (CEC) and Lime Requirement:

CEC reflects the ability of soil to retain nutrient cations. Soils with high CEC values ​​can absorb more cations and have a strong ability to buffer acid-base changes, but high CEC in acidic soils also means that more lime is needed to neutralize the acidity. For example, a soil with a CEC of 30 cmol (+)/kg may require 50% - 100% more lime to achieve the same pH improvement compared to a soil with a CEC of 15 cmol (+)/kg. Based on the CEC value and the target pH value, the lime application rate can be accurately calculated using the relevant formula to ensure accurate and effective improvement.

Nutrient content and lime application are related:

The nutrient content of nitrogen, phosphorus, potassium and other nutrients in the soil interact with lime application. In acidic soils, excessive aluminum and iron will fix phosphorus and reduce its effectiveness. Applying lime to increase soil pH can reduce phosphorus fixation and increase its effectiveness. For example, when the soil pH value increases from 5.0 to 6.5, the available phosphorus content in the soil may increase by 2-3 times. At the same time, the calcium in lime can promote the formation of soil aggregate structure, improve soil aeration and water retention, and facilitate the absorption of nitrogen, potassium and other nutrients by the root system. Therefore, when interpreting soil test results, it is necessary to consider the synergistic effects of nutrient content and lime application and formulate a scientific soil improvement plan.

4. Determining the Right Application Rate

Factors Influencing Lime Requirements

• Soil pH: Soil pH is a key factor in determining the amount of lime to apply. The ideal soil pH varies from crop to crop, but most crops thrive in a pH range of 6.0 to 7.5. For example, blueberries prefer acidic soils with an optimal pH of 4.0 to 5.5, while alfalfa is more adaptable to alkaline soils with an optimal pH of about 7.0 to 8.0. If the soil's current pH is far below the target, such as an acidic tea plantation with a pH of 4.5 and a target of 5.5, a large amount of lime will be needed to raise the pH. Generally speaking, for every 0.1 unit of soil pH below the target, an additional 50 to 100 pounds of lime may be applied per acre.
• Soil texture: Different soil textures require different amounts of lime. Clay soils retain more fertilizer and water than sandy soils, but they also have a stronger buffering capacity for lime. The large amount of colloidal particles in clay soils can absorb more ions, making the reaction more complex after lime application. In clay soils, 20% to 50% more lime may be required per acre than in sand soils to raise pH by the same amount. For example, 1,000 pounds of lime per acre in sand soils can raise pH by 0.5 units, while clay soils may require about 1,500 pounds.
• Cation Exchange Capacity (CEC): CEC reflects the soil's ability to absorb and exchange cations. The higher the CEC, the greater the soil's ability to retain nutrients and buffer changes in pH, and the greater the lime requirement. Soils with high CECs contain more negatively charged colloids that can absorb a large number of cations. For example, a soil with a CEC of 20 to 30 meq/100g may require 500 to 1,000 pounds more lime per acre to achieve the same soil pH adjustment effect than a soil with a CEC of 5 to 10 meq/100g.
• Crop Type: Different crops have different tolerance ranges and requirements for soil pH. Acid-tolerant crops such as tea trees and potatoes have strong adaptability to acidic soil environments and require relatively less lime; while crops that are sensitive to pH, such as sweet corn and onions, require more precise soil pH adjustment, and the amount of lime applied will be greatly adjusted according to the target pH and current soil conditions.
• Soil organic matter content: Soil organic matter can buffer soil pH changes. Soils with high organic matter content (such as organic matter content greater than 5%) can slow down the effect of lime on soil pH because they contain a large amount of acidic substances such as humus. In this type of soil, lime reacts with humus and other substances after application, and more lime is consumed to increase soil pH. Therefore, compared with low organic matter soils (organic matter content less than 2%), high organic matter soils may require 30% - 50% more lime per acre.

Calculating Lime Quantity per Acre

Calculation method based on soil test results:

• First, obtain soil pH, CEC, soil texture and other data through a professional soil testing laboratory. Assume that the soil test results show that the current soil pH is 5.0, the target crop is suitable for pH 6.5, the soil texture is loam, and the CEC is 15 meq/100g.
• Use the soil buffer curve or professional calculation formula to determine the amount of lime. The common formula for calculating lime demand is: lime dosage (pounds/acre) = buffer coefficient × (target pH - current pH) × CEC × soil bulk density × tillage depth. Among them, the buffer coefficient varies depending on the soil texture, and the buffer coefficient of loam is generally between 200-300. Assume that the soil bulk density is 1.2 g/cm³ and the tillage depth is 6 inches (about 15 cm, converted to 150,000 cm³/acre).
• Substitute the data into the calculation: the buffer factor is 250, (6.5 - 5.0) × 15 × 1.2 × 150000 × 250 = 843750000 (g), converted to pounds (1 pound = 453.592 grams), which is approximately 1,860 pounds per acre.

Refer to the recommendations:

Refer to the recommendations of local agricultural extension departments: Agricultural extension agencies in various regions will formulate reference standards for lime application suitable for the region based on local soil types, crop planting habits and long-term test data. For example, for rice growing in acidic red soil in a certain area, it is recommended to apply 1000-1500 pounds of slaked lime per acre when the pH value is 5.0-5.5; when the pH value is 4.5-5.0, apply 1500-2000 pounds. Farmers can refer to these recommendations to determine the approximate range of lime application based on the actual conditions of their own soil, and then fine-tune it based on the soil test results.

Field test method:

For newly developed farmland or farmland with uncertain soil characteristics, the field test method can be used. Divide the farmland into multiple plots, and apply different amounts of lime to each plot, such as setting different treatments of 0 pounds, 500 pounds, 1000 pounds, and 1500 pounds per acre. After a growing season, the crop growth conditions in different plots are observed, including plant height, leaf color, pest and disease occurrence, yield and other indicators. The lime application amount corresponding to the plot with the best crop growth is used as a reference for the subsequent application of the farmland. Although this method is time-consuming and labor-intensive, it can intuitively and accurately determine the most suitable lime application amount for local farmland.

Pelleting lime Application Methods

Equipment Selection: Spreaders and Sprayers

Pelletized lime spreader

Pelletized lime spreaders are mainly used in large open-air areas, such as farmland, pastures, golf courses, etc. In the agricultural field, spreaders are ideal when large areas of arable land need to be improved. For example, to adjust the pH value of the soil before wheat planting, a certain amount of granular lime needs to be spread per hectare, and spreaders can complete the work quickly and evenly.

Centrifugal spreader:

Pelletized lime is thrown out using a high-speed rotating disc. Its advantages are a wide spreading range, generally up to 8-15 meters, high working efficiency, and 5-10 hectares per hour. However, the uniformity of lime particles is required to be high, and large differences in particle size will lead to uneven spreading.

Pneumatic spreader:

Pelletized lime is blown out by compressed air, and the spreading amount can be accurately controlled. It can adapt to different terrains and can ensure uniform spreading even in undulating mountains. It is suitable for areas with extremely high requirements for spreading accuracy, such as vineyards and other economic crop planting areas, and its spreading error can be controlled within ±3%.

Pelletized lime spryer

Sprayers are suitable for spraying granular lime in liquid suspension, and are often used in some fine gardening, small greenhouses, or relatively small areas where the uniformity of lime distribution is extremely high. For example, in a greenhouse for flower cultivation, in order to accurately adjust the soil pH and avoid physical damage to flower seedlings caused by lime particles, granular lime can be made into a suspension and then applied with a sprayer.

• Backpack sprayer: Flexible operation, suitable for small-scale operations, such as home gardens or small nurseries. The capacity is generally 10-16 liters, and each full can spray about 200-400 square meters, which can meet the application needs of granular lime for small-scale gardening enthusiasts.
• Car-mounted sprayer: For larger orchards or vegetable plantations, car-mounted sprayers are more suitable. Its capacity can reach 200-1000 liters, equipped with high-pressure nozzles, it can spray the lime suspension evenly on the soil between crop rows, with high work efficiency, and can operate 2-5 hectares per day.

Step-by-Step Application Process

Pelletized lime spreader step-by-step process

• Preparation: First, determine the amount of granular lime to be applied based on the soil test results and the target improvement effect. For example, if the soil pH needs to be increased from 5.5 to 6.5, it is calculated that 1500-2000 kg of granular lime per hectare needs to be applied. Then, check the spreader equipment to ensure that all parts are operating normally, such as the flexible rotation of the disc of the centrifugal spreader and the stable pressure of the air pump of the pneumatic spreader. At the same time, calibrate the size of the spreader's outlet or adjust the pneumatic output to ensure the set spreading amount is accurate.
• Loading lime: Pour the granular lime slowly into the spreader hopper to avoid mixing with impurities and ensure that the lime can pass through the outlet smoothly. The hopper should not be loaded too full, generally maintained at 80%-90% of the hopper volume to prevent lime from overflowing during transportation and operation.
• Field work: Drive the spreader along the predetermined route at a constant speed. The driving speed is adjusted according to the type of equipment and spreading requirements, generally 3-6 km/h. For large areas of farmland, a round-trip or chessboard spreading path can be used to ensure uniform coverage of lime. During the operation, pay close attention to the discharge of the spreader. If abnormal discharge is found, the machine should be stopped immediately for inspection.
• Subsequent processing: After the operation is completed, clean up the lime remaining in the spreader hopper and discharge port in time to prevent caking and blockage. At the same time, conduct a comprehensive inspection and maintenance of the equipment to prepare for the next use.

Pelletized lime spryer step-by-step process

• Preparation of lime suspension: First, slowly add an appropriate amount of granular lime to clean water while stirring. Generally, the lime is prepared in a ratio of 1:10 - 1:20 (the specific ratio depends on the soil conditions and the purpose of application). The stirring time lasts for 15 - 30 minutes to ensure that the lime is fully suspended. To prevent precipitation, a small amount of suspending agent, such as sodium carboxymethyl cellulose, can be added. The amount added is 0.1% - 0.3% of the mass of the lime.
• Equipment preparation: Check whether the nozzle of the sprayer is blocked and whether the spray pressure is normal. The backpack sprayer can be manually pressurized to adjust the pressure to 0.2 - 0.4 MPa; the vehicle-mounted sprayer is provided with pressure by the vehicle power system, generally adjusted to 0.3 - 0.5 MPa. At the same time, calibrate the flow rate of the sprayer to ensure that the lime suspension can be sprayed according to the predetermined dosage.
• Field operation: The operator holds the sprayer nozzle or uses the vehicle-mounted spray device to evenly spray the lime suspension on the soil surface of the target area. For small areas, use an inside-out, spiral spray path; for large areas, spray in zones and rows. During spraying, keep the nozzle 30-50 cm away from the soil to ensure uniform spray coverage and avoid missed or double spraying.
• Cleaning equipment: After application, immediately clean the sprayer thoroughly with clean water, including the barrel, pipes and nozzles, to prevent lime residue from corroding the equipment. The cleaning water should be properly disposed of to avoid environmental pollution.

Safety Precautions During Application

Personal protection

• Wear protective clothing: Operators should wear long-sleeved work clothes, long pants and protective shoes to avoid direct skin contact with granular lime or its suspension. The material of the work clothes should be highly alkali-resistant, such as cotton canvas, which can effectively prevent lime from eroding the skin.
• Wear protective masks: Wear full-face gas masks to prevent inhalation of lime dust or suspension droplets. The mask must be equipped with high-efficiency filter elements that can filter particles with a particle size of more than 0.5 microns, with a filtration efficiency of more than 95% to protect the respiratory system from damage.
• Protective gloves and goggles: Wear rubber gloves to enhance hand protection and prevent lime from corroding the skin of the hands. At the same time, wear goggles to protect the eyes from splashing lime particles or suspensions. The goggles should have anti-impact and anti-chemical splash functions.

Equipment safety

• Equipment inspection: Before using the spreader or sprayer each time, strictly check the mechanical parts, electrical system (if any) and air system (for pneumatic equipment) of the equipment. For example, check whether the transmission belt of the spreader is loose and whether the pipe of the sprayer is broken to ensure the safe operation of the equipment and avoid safety accidents caused by equipment failure during operation.
• Pressure control: For the sprayer, the spray pressure must be strictly controlled and must not exceed the maximum working pressure specified by the equipment to prevent the pipe from bursting or the nozzle from falling off, causing the lime suspension to spray and injure people. At the same time, when adjusting the pressure, the operation should be slow to avoid sudden changes in pressure.

Environmental safety

• Avoid drift: When the wind is strong (more than level 4 wind), the spreading or spraying operation should be stopped to prevent the lime dust or suspension from being blown away by the wind and drifting to non-target areas, affecting the surrounding environment and personnel. If working near residential areas or water sources, isolation belts should be set up to reduce the potential pollution of lime to the environment.
• Proper disposal of waste: Waste such as discarded lime packaging bags, wastewater from cleaning equipment, and residual lime generated during the application process should be properly disposed of in accordance with environmental protection requirements. Waste packaging bags should be collected and collected in a centralized manner, and cleaning wastewater must be neutralized so that the pH value reaches the discharge standard of 6 - 9 before it can be discharged to avoid contamination of soil and water bodies.

Best Practices for Timing and Frequency

Optimal Seasons for pelletized lime Application

Best timing for agriculture uses

• Spring: In temperate climate zones, spring is the time for sowing or transplanting many crops, when soil temperatures gradually rise and microbial activity becomes active. Applying granular lime as soon as possible after the soil thaws in early spring can create a more suitable living environment for soil microorganisms and promote the decomposition of organic matter and nutrient conversion in the soil. For example, for acidic soils for growing corn, applying granular lime in March and April can effectively adjust the soil pH value in the early stage of crop growth, providing good soil conditions for corn seed germination and seedling growth. Studies have shown that in acidic soils with a pH of about 5.5, the germination rate of corn seeds increased by 15% to 20% after applying granular lime in spring compared to before application.
• Autumn: Autumn is also an ideal season for applying granular lime, especially after harvest. At this time, there is a lot of crop residue in the soil, and applying lime can help accelerate the decomposition of the residue, while avoiding the impact of rapid changes in soil pH on crops during the peak growth period. For orchard soil, applying granular lime after the fruit is picked in autumn (September-October) can effectively improve the physical and chemical properties of the soil through the autumn and winter seasons, providing sufficient nutrients and suitable soil pH for the growth of fruit trees in the following year. Taking apple orchards as an example, after applying granular lime in autumn, the effective phosphorus content in the soil increased by 10%-15% the following year, and the fruit quality and yield were improved.

Best timing for Horticulture and landscape field

• Before planting flowers in spring: For flower planting, applying granular lime in spring when preparing the planting bed is effective. Flowers are sensitive to soil pH. Before planting alkaline-loving flowers (such as geraniums and roses), adjusting the soil pH to the appropriate range (6.0-7.0 for geraniums and 6.0-6.5 for roses) by applying granular lime can promote the growth of flower roots and nutrient absorption, and improve the disease resistance and flowering quality of flowers. Apply granular lime 2-3 weeks before planting and let it mix well with the soil for the best effect.
• Autumn lawn maintenance: When maintaining the lawn in autumn, applying granular lime can improve the compaction of lawn soil, adjust the soil pH, and enhance the cold resistance of lawn grass. For lawn soils with strong acidity (pH value below 5.5), applying granular lime in October-November can keep the lawn grass in good color and growth state in winter and reduce the occurrence of winter lawn diseases. For example, in golf course turf maintenance, the proper application of granular lime in autumn can significantly improve the smoothness and durability of the turf.

Frequency of Reapplication

Soil type and pH change

• Highly acidic, sandy soil: Sandy soil has poor fertilizer and water retention capacity, and alkaline substances in the soil are easily lost with rain or irrigation water, resulting in rapid changes in soil pH. For highly acidic sandy soils (pH value below 5.0), granular lime may need to be re-applied every 1-2 years to maintain the soil pH value in the range suitable for crop growth (generally 6.0-7.0). During the continuous monitoring of soil pH, if the soil pH value drops by more than 0.5 units in a year, re-application of granular lime should be considered for adjustment.
• Clay soil: Clay soil has fine particles, strong fertilizer and water retention capacity, and relatively stable soil pH. For clay acidic soils (pH value between 5.0-5.5), the frequency of re-application of granular lime can be appropriately reduced, generally once every 3-4 years. This is because clay soil has a strong buffering capacity for lime, and lime acts in the soil for a relatively long time. However, if the soil has been used for a long time with high intensity, such as planting high-fertilizer crops for many consecutive years and applying a large amount of acidic fertilizers, resulting in a significant decrease in soil pH, the frequency of re-application of granular lime should also be adjusted in time.

Crop type and planting system

• High calcium-demanding crops: Some crops such as broccoli, carrots, tomatoes, etc. have high calcium requirements and are sensitive to soil pH. For the soil for planting such crops, in order to ensure that the crop continues to obtain a suitable soil environment during growth, it may be necessary to re-apply granular lime every 1-2 years according to the crop growth cycle and soil conditions. For example, in broccoli planting, after two consecutive years of planting, the calcium in the soil will be consumed, and the soil pH may decrease. At this time, timely re-application of granular lime can improve the yield and quality of broccoli, increase the firmness of broccoli heads by 10%-15%, and increase the vitamin C content by 8%-12%.
• Rotation system: Under the planting system of different crop rotations, the frequency of re-application of granular lime also needs to be adjusted accordingly. If there are crops in the rotation that have very different requirements for soil pH, such as planting rice, which is more tolerant to acidic environments, first in acidic soil and then planting soybeans, which are more sensitive to soil pH, then before planting soybeans, it may be necessary to re-evaluate the need for granular lime based on soil test results. Generally speaking, after a round of crop planting, soil pH testing should be carried out to determine whether granular lime needs to be re-applied and the amount of application based on the test results to meet the growth needs of the next round of crops.

Comparing Pelletized Lime with Other Soil Amendments

Pelletized Lime vs. Agricultural Lime

Differences in Composition and Effectiveness

Composition difference

• Agricultural lime usually refers to the product made by simply crushing natural limestone. Its main component is calcium carbonate (CaCO₃), but the impurity content is relatively high, and the purity is mostly 70% - 90%. Its ore sources are wide, resulting in large fluctuations in composition. In addition to calcium carbonate, agricultural lime from different origins contains different types and proportions of impurities such as magnesium, iron, and aluminum.
• Pelletized lime is generally processed more finely, and the raw material is high-purity limestone, and the purity of calcium carbonate often exceeds 95%. During the production process, specific additives may be added or modified according to demand to optimize performance. For example, some pelleting lime used in special industrial processes will control the content of trace elements to ensure that no interfering impurities are introduced in complex chemical reactions.

Effect difference

• Agricultural lime dissolves and reacts slowly in the soil due to its rough particles and uneven size. Studies have shown that it often takes 3-5 years for it to completely decompose and have a significant impact on the pH value of the soil. This makes it difficult to quickly adjust the soil pH, which is not conducive to timely improving the crop growth environment. For example, in tea garden soil with strong acidity, after applying agricultural lime, it may take 2-3 growing seasons for the soil pH value to increase by 0.5-1 unit.
• Pelleting lime particles are uniform, with a large specific surface area, sufficient contact with the soil, and faster dissolution and reaction. After being applied to the soil, it can begin to significantly change the soil pH within 1-2 months, and the soil pH value can be stably increased by 1-2 units in 6-8 months, quickly creating a suitable growth environment for crops. Moreover, because it is more evenly distributed in the soil, the effect of soil improvement is more stable and lasting, which can effectively avoid local soil pH imbalance.

Cost-Benefit Analysis

Category	Agricultural Lime	Pelletizing Lime
Procurement Cost	Simple production process, mainly involves crushing, leading to a lower cost (100-300 RMB per ton). However, due to lower purity and higher impurities, a larger application amount is required to achieve the desired effect.	Complex processing, including raw material selection, fine grinding, and granulation, resulting in a higher cost (400-800 RMB per ton). However, due to high purity and efficiency, the application amount is only 60%-80% of agricultural lime for the same soil improvement area.
Long-Term Benefits	Slow decomposition with less noticeable long-term effects. Soil improvement may be insufficient, affecting crop yield and quality. In acidic soil regions, even with continuous application, crop yield increases slowly. For some economic crops (e.g., strawberries), yield improvement is less than 10%, with limited enhancement in fruit quality (e.g., sweetness, color).	Rapid and effective soil improvement, significantly boosting crop yield and quality. In the same acidic soil, vegetable yield increases by 20%-30% after application. The fruits are fuller, taste better, and have a higher market price. Additionally, it reduces labor and material costs associated with frequent fertilization and soil amendments, making it more cost-effective in the long run.

Pelletized Lime vs. Liquid Lime

Application Methods and Efficiency

Pelletized lime:

• Application method: Granular lime is usually applied with the help of agricultural machinery such as fertilizer spreaders and seed drills. There are many types of fertilizer spreaders, such as centrifugal fertilizer spreaders, which evenly spread granular lime through high-speed rotating fertilizer spreaders. In actual operation, the mechanical parameters can be adjusted according to the size and shape of the plot and the required application amount, such as adjusting the speed of the fertilizer spreader and the size of the discharge port.
• Efficiency data: Taking the common large-scale farmland operation as an example, a tractor equipped with a suitable fertilizer spreader can operate an area of ​​8-12 hectares per hour. This is because granular lime has good fluidity and smooth mechanical transportation, which can quickly and evenly spread lime on the soil surface. Moreover, due to its stable particle shape, it is not easy to drift or accumulate in the case of mechanical vibration or low wind force, ensuring that each piece of land can get a relatively accurate application amount.

Liquid lime:

• Application method: Liquid lime is generally applied with spray equipment, such as backpack sprayers and vehicle-mounted large sprayers. The sprayer sprays liquid lime in a mist form onto the soil surface under pressure. During operation, parameters such as spray pressure, nozzle flow rate, and spray height need to be strictly controlled to ensure uniform coverage of liquid lime.
• Efficiency data: When a large vehicle-mounted sprayer is operating on a large area of ​​farmland, the operating area per hour is about 5-8 hectares. However, liquid lime is greatly affected by wind force during spraying. When the wind speed exceeds 3-4 m/s, the droplets are easy to drift, resulting in insufficient application in some areas and excessive application in some areas, affecting the application effect and efficiency. According to research, under strong wind conditions (5-6 m/s), the effective utilization rate of liquid lime may be reduced by 20%-30%. Moreover, the spray equipment needs to be strictly cleaned before and after use to prevent residual liquid lime from clogging the nozzle or corroding the equipment, which also increases the operating time cost to a certain extent.

Suitability for Different Soil Types

Pelletized lime:

• Sandy soil: Sandy soil has large particles and large pores, good air permeability but poor fertilizer and water retention. After granular lime is applied, it can slowly dissolve in the soil pores, continuously release alkaline substances such as calcium ions, and adjust the soil pH. Because of its large particles, it is not easy to be lost quickly with water infiltration. Studies have shown that in sandy acidic soil with a pH value of 5.0-5.5, applying 1.5-2.0 tons of granular lime per hectare can increase the soil pH to 6.0-6.5 after one growing season, and the effective calcium content in the soil increases by 20-30 mg/kg, which helps to improve the soil aggregate structure and improve the fertilizer and water retention capacity.
• Clay soil: Clay soil has fine particles, small pores, poor air and water permeability, and is often highly acidic. Although granular lime dissolves relatively slowly in clay soil, it can gradually diffuse in the soil due to its good stability. In the experiment of clayey acidic soil with pH value of 4.5-5.0, 2.0-2.5 tons of granular lime were applied per hectare. After two growing seasons, the soil pH value can be increased to 5.5-6.0, and the soil bulk density is reduced by 0.1-0.2 g/cm3, which improves soil aeration and water permeability, and is conducive to the growth of crop roots.
• Loamy soil: Loamy soil has the advantages of both sandy soil and clay soil, and is an ideal agricultural soil type. Granular lime can play a better role in loamy soil, and can be evenly distributed and moderately dissolved after application. In loamy soil, applying 1.0-1.5 tons of granular lime per hectare can maintain the soil pH value in the range of 6.5-7.5 suitable for crop growth, promote soil microbial activity, improve soil nutrient effectiveness, and increase crop yield. For example, in loamy soil for wheat cultivation, the reasonable application of granular lime can increase wheat yield by 10%-15%.

Liquid lime:

• Sandy soil: After liquid lime is applied to sandy soil, it will quickly infiltrate due to its strong fluidity, resulting in a short residence time on the soil surface and insufficient contact reaction with soil particles. In sandy soil, the active ingredients in liquid lime may be lost to the deep soil too quickly with water, and cannot effectively adjust the pH of the surface soil. Studies have shown that when liquid lime is applied to sandy soil, only 30% - 40% of the active ingredients can play a role in the surface 0 - 20 cm soil, and the effect on improving soil pH is limited. Moreover, frequent application of liquid lime may further destroy the already weak aggregate structure of sandy soil, reducing the soil's ability to retain fertilizer and water.
• Clay soil: Clay soil has small pores, and liquid lime moves slowly in it, which can easily cause local excessive concentration, which has adverse effects on soil microorganisms and plant roots. At the same time, after liquid lime dries in clay soil, it may form a hardened layer, which hinders soil ventilation and water penetration. In clayey acidic soils with a pH of 4.5 - 5.0, even if the application rate of liquid lime is increased to 3.0 - 3.5 tons per hectare, the soil pH can only be raised to 5.0 - 5.3 after one growing season, which is not as effective as granular lime.
• Loamy soil: In loamy soil, the application effect of liquid lime is relatively good. It can react with soil particles quickly to adjust the soil pH. In loamy soil, applying 0.8 - 1.2 tons of liquid lime per hectare can increase the soil pH in a short period of time. However, because liquid lime is greatly affected by environmental factors (such as temperature and humidity), its effect is not as stable as granular lime. For example, in hot and dry seasons, liquid lime evaporates quickly, the effective ingredients are lost a lot, and the effect of adjusting soil pH will be greatly reduced.

Integrating Pelletized Lime with Fertilizers

Compatibility and Combined Benefits

• Chemical compatibility: Pelletizing lime is chemically compatible with most common fertilizers. Lime is mainly composed of calcium oxide (CaO) or calcium hydroxide (Ca (OH)₂), which is alkaline. For example, nitrogen fertilizers such as urea (CO (NH₂)₂) and ammonium sulfate ((NH₄)₂SO₄) will not undergo violent chemical reactions that cause the fertilizer to become ineffective when mixed with granular lime. Studies have shown that under laboratory simulation conditions, when a proper amount of pelleting lime and urea are mixed in a certain proportion and stored for 30 days, the nitrogen content of urea is only lost by 2% - 3%, which is within the acceptable range for agricultural production. For phosphate fertilizers, such as superphosphate (Ca (H₂PO₄)₂・H₂O), although the alkalinity of lime may slightly reduce the effectiveness of phosphorus in the soil in the short term, in the long term, after lime adjusts the soil pH to the appropriate range of 6.5 - 7.5, the overall utilization rate of phosphorus in the soil can be increased by 10% - 15%. Because in acidic soils, phosphorus is easily combined with elements such as iron and aluminum to form insoluble compounds, and lime reduces this fixation effect after raising the pH value.
• Synergistic promotion of plant growth: The combination of the two can provide more comprehensive support for plant growth. Pelletizing lime improves soil pH, creating a favorable environment for the release of fertilizer nutrients and plant root absorption. In acidic soils, when nitrogen fertilizers are applied alone, nitrogen is easily leached due to soil acidity, and the loss rate can reach 30% - 40%. However, when used in combination with granular lime, soil acidity is reduced and nitrogen leaching is reduced to 10% - 15%. At the same time, the calcium provided by lime helps to strengthen the cell wall of plants and improve the ability of plants to resist lodging, while the nitrogen, phosphorus, potassium and other elements in fertilizers are directly involved in the photosynthesis, energy metabolism and other physiological processes of plants. For example, in the corn planting experiment, the stalk hardness of corn plants in the plots where pelletized lime and nitrogen, phosphorus and potassium compound fertilizers were applied at the same time was 15% - 20% higher than that in the plots without lime application, and the corn yield was 12% - 18% higher than that of the plots where fertilizers were applied alone.
• Improvement of soil structure and fertility: Pelletizied lime combined with fertilizers can optimize soil structure and long-term fertility. The calcium ions in lime can promote the aggregation of soil particles, form a good aggregate structure, and increase soil porosity. Studies have shown that the simultaneous application of granular lime and organic fertilizers in farmland for three consecutive years increased soil porosity by 8% - 12%, improved soil aeration and water permeability, and facilitated the diffusion of fertilizers in the soil and the absorption of nutrients by roots. Moreover, after lime adjusts the pH of the soil, it can activate some beneficial microorganisms in the soil, such as nitrifying bacteria and nitrogen-fixing bacteria. Compared to soil without lime application, the number of nitrifying bacteria in soil with lime and fertilizer applied simultaneously increased by 2-3 times, which accelerated the conversion of nitrogen in the soil and further improved soil fertility.

Timing Considerations for Joint Application

• Determined based on soil conditions: In strongly acidic soils with a soil pH value below 5.5, priority should be given to applying granular lime to adjust the soil pH and create conditions for subsequent fertilizer application. It is generally recommended to apply lime 2-3 months before sowing so that the lime has enough time to fully react with the soil. For example, in acidic tea garden soils in the south, if you plan to plant tea trees in spring, apply 2-3 tons of pelletized lime per hectare in the autumn of the previous year. After winter weathering and soil mixing, the soil pH value can be increased by 0.5-1.0 units in spring. At this time, applying basal fertilizer can better exert the effect of fertilizer. On the contrary, if the soil pH value is close to neutral or slightly alkaline, lime can be applied at the same time or slightly later than fertilizer according to the crop fertilizer requirement law and soil nutrient test results, but the interval should not exceed 1 month to avoid lime from having an adverse effect on the effectiveness of fertilizer nutrients.
• Combined with the crop growth stage: For annual crops, such as wheat, pellet lime can be mixed with organic fertilizers, phosphate fertilizers, etc. in the basal fertilizer stage. The amount of lime applied per hectare is about 1-2 tons according to the soil pH, which provides a good soil environment and nutrient basis for wheat in the early growth stage. During the wheat jointing stage, granular lime can be applied in appropriate amounts according to the soil pH value and seedling conditions, generally 0.5-1 tons per hectare, and nitrogen fertilizer can be applied at the same time to promote wheat stem growth and ear differentiation. For perennial fruit trees, such as apple trees, after fruit harvesting in autumn, granular lime can be mixed with organic fertilizers and compound fertilizers in combination with deep plowing and soil improvement. 0.5-1 kg of lime can be applied per plant. At this time, the soil temperature is still high, which is conducive to the reaction between lime and soil and the decomposition and conversion of fertilizers, and reserves nutrients for the growth of fruit trees next year. 1-2 months before the flowering of fruit trees, a small amount of granular lime can be applied again, 0.2-0.3 kg per plant, to adjust the soil microenvironment and increase the fruit setting rate, according to the soil pH and leaf yellowing and other nutrient deficiency symptoms.
• Consider climate factors: In areas with frequent rainfall, avoid applying large amounts of limestone pellets and fertilizer before the rainy season to prevent the nutrients of lime and fertilizer from being washed away by rain. For example, in the southeastern coastal areas of my country, there are many typhoons and rainstorms in summer. If lime and fertilizer are applied within 1-2 weeks before the typhoon arrives, the nitrogen leaching rate in the fertilizer may be as high as 50%-60%, and the lime cannot fully play its role in regulating the pH of the soil. The best time to apply is after the rainy season when the soil moisture is suitable, which can not only ensure that the lime and soil are fully in contact and react, but also allow the fertilizer nutrients to be effectively retained in the soil for crop absorption. In arid areas, pellets lime and fertilizer can be applied in appropriate amounts before irrigation. Irrigation water can promote the diffusion and dissolution of lime and fertilizer in the soil and improve their utilization rate. However, care should be taken to control the amount of irrigation water to avoid fertilizer leaching and soil compaction due to excessive water.

FAQ: Common Questions About Pelletized Lime

Conclusion:

In summary, pelletized lime has shown many significant advantages in agriculture, horticulture, environment, and industry. It can effectively improve soil structure and soil fertility. By accurately adjusting the soil pH value, it can create an ideal environment for the growth of crops and green plants, and significantly improve crop yield and quality. Compared with traditional agricultural lime, limestone pellets have outstanding performance in terms of ease of application, reduction of dust pollution, and accelerated soil fusion. Its application range is also wider, from farmland to lawn gardens, from water treatment to waste management, and it plays an indispensable role.

When using pelletizing lime, the correct application method is crucial. Conducting comprehensive soil tests, determining the precise application ratio based on the test results, and using appropriate equipment and operating procedures, and following the best application time and frequency are the keys to fully exerting the effectiveness of pelleting limestone. At the same time, when compared and used in conjunction with other soil conditioners and fertilizers, pelletized lime also shows unique compatibility and synergistic benefits.

Limestone pellets are indeed a valuable soil improvement material. It is strongly recommended for farmers, gardeners, and practitioners in related industries.