READ a rock dust primer
Frequently Asked Questions
Q: What is Remineralization?
A: Remineralization is the utilization of natural broad elemental spectrum rock dust materials for the purpose of renewing the mineral content of soils and other growing media.
Q: Which Type of Rock Dust Should I Choose?
A: After nearly 25 years evaluating and working with rock dusts from all over North America we feel the best rock dusts for soil remineralization are volcanic geologic materials such as the Basalts and Metamorphic and Sedimentary types characterized by a rich diversity in minerals. This is how we came to define the BEST; as the Broad Elemental Spectrum Tectonic. Tectonic means "forces which shape the earth". Examples of these are found in the regional Volcanic magmas, such as the Pioneer Valley Basalt found in New England, regional Schists and Shales such as the Ashfield, Greenstone, St. George Black, and regional Clays such as the Diatomite/Montmorillonite, containing a diversity of nutritive materials, including volcanic magma and ash, diatoms, silicates, carbonates, humic and carbonaceous compounds. There are many clay-like geologic deposits being mined in the western regions for soil amendments and industrial uses, some have become famous marketed under trade names such as Azomite. Sand and gravel placers can also be very rich and diverse, such as the glacial moraines and the alluvial loess and silts. There are also the exotic and rare prospects with unique attributes. We introduced the Ruby MT Feldspar/Hornblende for its unique geologic profile from the roots of the Adirondacks with its content of silica, and gem garnet fractions sought after by BioDynamic growers, with subtle optic and piezo resonance and slow release nutritive properties. Paramagnetism is a magnetic attribute with quantifiable positive effects on plant growth found in high quality rock dusts. The volcanic Zeolites are commodity minerals with special electrical properties such as cation exchange capacity, used for filtering and mitigating toxicity in soils and water. Rich reactive liming materials such as the Wollastonite, a form of Calcium Silicate, and the Carbonatite, a volcanic carbonate-rich magma are found in rare economic deposits. Concentrates rich in individual elements such as Phosphorus are found in sediments such as the famous Tennessee Brown Rock Phosphate. Lignite, a form of brown coal, contains both carbon and humic substances and its extracts are a growing favorite among traditional organic farmers and indoor horticulturalists. Historically, the Granites have been favored by fruit and potato growers because of the potassium content and regional availability. "Bread From Stones" published by Julius Hensel in the mid 1800's, focused on Granite as one of the valuable "local rocks for local crops" at term coined by Prof. Peter Van Straaten. In short, there are a variety of useful and unique geologic materials in many locations, and we try to offer these in economic supply whenever possible. See the Store, Catalogs, and the BioChar pages for our current selections.
Q: Is Glacial Rock Dust Better than Single Geologic Sources like Basalt?
A: Not necessarily. Over 30 years ago one of the founding fathers of remineralization, John Hamaker, promoted the use of glacial and alluvial rock dusts for remineralization. This choice was based on his objective of emulating glacial forces in revitalizing the planet through remineralization. However, when comparing scores of mineralogical and geochemical analysis and actual field tests in current practice, we generally favor the single source volcanic geologic types such as the Basalts and the complex Metamorphic and Sedimentary rocks and Clays over the regional glacial and alluvial sands and gravels. This is not at odds with Hamaker's objective. Volcanic magmas are primary movers in tectonics, which are forces which shape the earth, and they play an essential role in the carbon cycle. Though we have found some very excellent glacial deposits, and offer some of the BEST we have found, on balance the glacial and alluvial materials are harder to quantify, more difficult to predict in uniformity of analysis over time, and generally poor in mineralogical content in comparison to the singular volcanic geology or the rich metamorphic conglomerate rocks, diverse hard rock sediments and clays. This is because as the glacial and alluvial sediments move from their original location many of the useful minerals weather away, leaving the harder, less nutritive materials in tact, as well as some of the heavier elements. Additionally, "Guaranteed" or "Typical" certified analysis are virtually impossible for glacial or alluvial sources, as the mineralogy will change from strata to strata even within a single mine. We have also quarantined more glacial and alluvial prospects than any other source type because of concentrations of heavy elements or other toxins, as these tend to settle and concentrate in the placers. This is an entirely natural process and easily verified in the data.
Q: What are the differences in gradations?
A: Gradation means the size and distribution of the particles in the sieve analysis. We refer to three basic gradations in common terms. More technical specifications can be applied to these common terms as well. The "grits-to-dust" is typically any rock dust with a course fraction in the particle size. The largest particle for our purposes can be passing through a 1/4" screen with the dust included or it can be finer, i.e., 1/8"-0 and finer still. The premium BrixBlend gradation is typically 10 mesh (2mm) to dust with about 50% of this passing 200 mesh screen. The 200 mesh and passing is referred to as the Microfine gradation and the Stone Flours. 200 mesh is .0029" (.074mm), i.e., dust. There can be some small variations within these materials depending on the source and the way the materials are produced. Generally the Microfines will be the finest, the Stone Flours may contain a slightly larger particle, more like flour than pure dust. A Silt gradation is typically a very fine sand with a high fraction of stone flour mixed together. This is generally a damp material derived from pond dredging or dewatered slurries.
Q: How Much Rock Dust Do I Use?
A: Application rates will vary according to usage, soil type and condition. Field trials indicate that a direct benefit exists between application rate and increase harvest weight starting at very low rates and running up through very high rates, up to 250% increase in harvest weight over the controls. (Goreau et. al, New Harmony Farm 2012) Rock dust for remineralization has traditionally been utilized at very high rates, up to 10 tons per acre. However the science indicates that low rates of high value rock dust containing a highly micronized fraction will have immediate and lasting benefits. With this in mind, usage protocols can be built around management practice, economics, size of growing area, type of crop etc. For professional soil management practices use of soil tests, careful analysis of rock dust geochemistry and mineralogy, identifying 'limiting factors' in current growing practices and a careful comparison of available rock dusts for targeted use and annual usage rates can provide measurable benefits.
For a less scientific approach, a liberal application of the BEST rock dust in a suitable gradation works. The risk of 'burning' or damaging crops within maximum application rates is virtually nil.
General rules of thumb can help determine application rates. There are 43,560 square feet/acre. If your application rate is 1 ton/acre you will use 5 lbs/100 square feet. Limitations will be determined by soil pH, organic matter in soil and spreading capacity. Choice of particle size, specific geologic make up, proximity of the source and your volume requirements will also determine annual usage and actual rock dust material used in bulk applications.
Here are some general guidelines: In tillage for remineralization purposes; Between 5 and 10 tons/acre of a course stone dust passing (1/4" screen to dust) have been used to advantage. That converts to 25 - 50 lbs material/ 100 square feet in tillage. There is no harm in using less, the results will be determined by the interaction of the rock dusts with the soil media. The highly micronized gradations will work faster as the surface area is greater/ lb. of material. So application rates can be less in the first year to achieve the same growth response. The BrixBlend gradation was formulated to optimize both mechanical attributes of the larger particle with the larger surface area of the micronized material for use in growing media, soils or soil-less. Field research has shown that "the more you use the better" right up to very high application rates (20 tons/acre) before the direct correlation between application rate and yields diverge. See the New Harmony Farm test results for this data on the Home page. For professionals, we recommend working the materials into your management and budget allowances, and use enough material to take advantage of that potential in year one. This will improve your bottom line and may give you some room for adopting more intensive biologic methods, which will optimize both nutritional content and profitability. In some states regulations will limit the amount of material that can be applied in a given year based on metal concentrations in fertilizers or soil amendments. Research with silicate rock dusts indicates that 'availability' and mobility of mineral complexes is governed largely by 'weathering', i.e. mechanical and chemical action of the soil environment and biological activity of soil biota. As such mineral complexes are very stabile in the soil matrix especially within normal pH parameters. For the agronomist the certified geochemical analysis provided with each material can be used as a baseline reference for determining application rates in a given year. We can help design your management strategy based on your parameters.
For direct to ground top dressing of hay land, lawn or turf; 2 - 5 tons/acre of a 50% micronized material can be utilized (100% passing 2 mm screen and 50%+ passing 200 mesh screen such as the Pioneer Valley Basalt "BrixBlend") That converts to 10 - 25 lbs/ 100 square feet.
For maintaining foundation fertility after initial remineralization; Very low rate foliar applications or fertigation of 5-25 lbs/acre of the highly micronized gradations will provide nutrient and energy loads once or more times per season. 1 - 2 tons/acre can be used as a top dressing or incorporated during tillage every 1 to 3 years depending on production and crop rotation. That converts to 5 - 10 lbs./100 square feet. Seven year rotation cycles can also be integrated with rock dust applications over fallowed ground.
We strongly recommend the use of aqueous solutions of micronized minerals and inoculants for foliar, fertigation and drenching during the growing season. The rock dust minerals in
direct-to-ground applications provide the foundation of fertility upon which good intensive nutrient dense management practices rest. Need help with this? Contact us. We're here to help.
Q: When is the best time of year to apply rock dust?
A: Spring tillage is traditional but fall applications can be even better. Apply rock dust powders with other amendments at the same time. Fall tillage or top dressing applications are also excellent as the rock dust incorporated in the fall assimilates over the winter and is available during the spring growing season. I.e., Apply with planting of overwintering tubers such as garlic, broadcast over hay land, or pasture. Rock dust can be applied whenever cover crops are tilled in preparation for new plantings. The charge of micronized minerals will stimulate microbial populations and make the nutrients more available to the new crop. Micronized rock powders can be suspended in water for 'fertigation' and foliar use during the growing season. Top dressing or side dressing can also be done during the season at any time.
Q: How do I spread rock dust?
A: Pulverized rock powders can be spread in traditional lime drill drop spreaders with large openings in the trough. Any damp lime spreader wagon or truck mounted sand and salt spreader will spread any gradation of rock dust except the dry stone flours or "Microfines". The grits-to-dust gradations can be spread like lime, in live floor lime spreaders and augur driven applicators. Microfines and Stone flours can be entrained in water for foliar or fertigation applications or to create slurries and conveyed using diaphragm or rotor-stator pumps. Rock dust can also be added to manure spreaders on top of the load. Please note: Pulverized rock powders will not spread in cone type three point hitch setups. These require granulated or pelleted materials. Caution! Rock dusts often contain silica. Dry stone powders present a breathing hazard. Wear suitable respirators and limit exposure.
Spreading methods by gradation:
Grits-to-dust are suitable for broadcast in live bottom spreaders, wet or damp lime spreaders large drop spreaders, sand and salt type spreaders, or by hand. Stone flours can be spread in drop spreaders or by hand, or pumped in suspensions. Silt gradations can be spread in live bottom wet or damp lime spreaders, sand and salt type spreaders or by hand.
Q: Can I use rock dust in making compost?
A: Yes! Good results have been achieved using 20-25lbs micronized high silica, calcium rich rock dusts/ cubic yard of compost raw material. (We ship the Basalt Microfines and the Ruby Mountain 'True Stone Flour' for this purpose.) You can mix these different geologic sources together to take advantage of each, or use them undivided. This is an excellent way to assimilate the minerals within the biologic system in the soils, making the nutrients available to the plants. Rock Dust Local strongly recommends building compost with the BEST* micronized rock powders as well as blending rock dusts of courser gradation to finished compost material. True Remineralized compost will be built with rock (not just mixed with it post digestion). There is a difference!
Q: How does rock dust compare to conventional synthetic fertilizers?
A: There is little comparison. Many synthetic petroleum derived fertilizers are acid salts or soluble sulfates of a very narrow elemental spectrum, often containing a single elemental nutrient in combination with Chlorine or Sulfur. Chemical fertilizers are usually a combination of
three elements; N, P, and K (Nitrogen, Phosphorus and Potassium) delivered in soluble form. The broad elemental spectrum rock dusts contain a naturally occurring distribution of macro and micro nutrients delivered in mineral form, are generally insoluble crystaline structure and rely on weathering and an active soil biology consisting of beneficial bacteria and fungi to assimilate the mineral elements, making the nutrients available to the plants as needed.Highly micronized fractions of rock dust blends are immediately available to biologic systems and are highly effective in building amino acids and enzymes critical for biologic systems. There is little or no nitrogen in most rock dust materials although essential elements for fixing nitrogen in soils such as Molybdenum and Vanadium are present in many high quality rock dusts. The use of fixed carbon and humic sources are encouraged as companion materials to the broad elemental spectrum rock dusts to help build soil biology and regulate the uptake of essential nutrients in plants. Soil remineralization is a method of encouraging a natural, sustainable and self regulating growing environment which promotes long term and sustainable fertility.
Q: Is there any way to measure the effectiveness of rock dusts?
A: Yes. Annual soil testing should show improvements in both available nutrients and overall nutrient density in soils. Additionally, Brix meter readings should improve, indicating higher sugar and mineral content in plants. Tissue analysis of produce and forage should indicate increased mineral and nutrient value. Overall improvement in plant vigor should follow the assimilation of minerals in the rock dust.
Q: Do I still need to use fertilizers when I apply rock dusts?
A: Initially soils which are seriously depleted of certain mineral nutrients and microbial populations will need to be restored with a combination of macro and micro nutrients, inoculants and fixed carbon sources in addition to the broad elemental spectrum rock dusts. Thereafter, a reliance on the narrow elemental spectrum fertilizer inputs may diminish with good management, crop rotations, adequate use of humic materials, fixed carbon and applications of broad elemental spectrum rock dusts. Most rock dust materials cannot be considered fertilizers in the conventional definition of high soluble doses of N-P-K. These major nutrients will still need to be managed whatever practice is being employed. Rock dusts for remineralization are used to establish a foundation of fertility that good nutrient management rests upon. See resource links on the home page for more information.
MORE INFORMATION and INTERVIEWS WITH THOMAS VANACORE (founder Rock Dust Local):
View John Kohler's Growing Your Greens Videos! And if you wish to purchase packaged rock dust go to the web store>
A: Remineralization is the utilization of natural broad elemental spectrum rock dust materials for the purpose of renewing the mineral content of soils and other growing media.
Q: Which Type of Rock Dust Should I Choose?
A: After nearly 25 years evaluating and working with rock dusts from all over North America we feel the best rock dusts for soil remineralization are volcanic geologic materials such as the Basalts and Metamorphic and Sedimentary types characterized by a rich diversity in minerals. This is how we came to define the BEST; as the Broad Elemental Spectrum Tectonic. Tectonic means "forces which shape the earth". Examples of these are found in the regional Volcanic magmas, such as the Pioneer Valley Basalt found in New England, regional Schists and Shales such as the Ashfield, Greenstone, St. George Black, and regional Clays such as the Diatomite/Montmorillonite, containing a diversity of nutritive materials, including volcanic magma and ash, diatoms, silicates, carbonates, humic and carbonaceous compounds. There are many clay-like geologic deposits being mined in the western regions for soil amendments and industrial uses, some have become famous marketed under trade names such as Azomite. Sand and gravel placers can also be very rich and diverse, such as the glacial moraines and the alluvial loess and silts. There are also the exotic and rare prospects with unique attributes. We introduced the Ruby MT Feldspar/Hornblende for its unique geologic profile from the roots of the Adirondacks with its content of silica, and gem garnet fractions sought after by BioDynamic growers, with subtle optic and piezo resonance and slow release nutritive properties. Paramagnetism is a magnetic attribute with quantifiable positive effects on plant growth found in high quality rock dusts. The volcanic Zeolites are commodity minerals with special electrical properties such as cation exchange capacity, used for filtering and mitigating toxicity in soils and water. Rich reactive liming materials such as the Wollastonite, a form of Calcium Silicate, and the Carbonatite, a volcanic carbonate-rich magma are found in rare economic deposits. Concentrates rich in individual elements such as Phosphorus are found in sediments such as the famous Tennessee Brown Rock Phosphate. Lignite, a form of brown coal, contains both carbon and humic substances and its extracts are a growing favorite among traditional organic farmers and indoor horticulturalists. Historically, the Granites have been favored by fruit and potato growers because of the potassium content and regional availability. "Bread From Stones" published by Julius Hensel in the mid 1800's, focused on Granite as one of the valuable "local rocks for local crops" at term coined by Prof. Peter Van Straaten. In short, there are a variety of useful and unique geologic materials in many locations, and we try to offer these in economic supply whenever possible. See the Store, Catalogs, and the BioChar pages for our current selections.
Q: Is Glacial Rock Dust Better than Single Geologic Sources like Basalt?
A: Not necessarily. Over 30 years ago one of the founding fathers of remineralization, John Hamaker, promoted the use of glacial and alluvial rock dusts for remineralization. This choice was based on his objective of emulating glacial forces in revitalizing the planet through remineralization. However, when comparing scores of mineralogical and geochemical analysis and actual field tests in current practice, we generally favor the single source volcanic geologic types such as the Basalts and the complex Metamorphic and Sedimentary rocks and Clays over the regional glacial and alluvial sands and gravels. This is not at odds with Hamaker's objective. Volcanic magmas are primary movers in tectonics, which are forces which shape the earth, and they play an essential role in the carbon cycle. Though we have found some very excellent glacial deposits, and offer some of the BEST we have found, on balance the glacial and alluvial materials are harder to quantify, more difficult to predict in uniformity of analysis over time, and generally poor in mineralogical content in comparison to the singular volcanic geology or the rich metamorphic conglomerate rocks, diverse hard rock sediments and clays. This is because as the glacial and alluvial sediments move from their original location many of the useful minerals weather away, leaving the harder, less nutritive materials in tact, as well as some of the heavier elements. Additionally, "Guaranteed" or "Typical" certified analysis are virtually impossible for glacial or alluvial sources, as the mineralogy will change from strata to strata even within a single mine. We have also quarantined more glacial and alluvial prospects than any other source type because of concentrations of heavy elements or other toxins, as these tend to settle and concentrate in the placers. This is an entirely natural process and easily verified in the data.
Q: What are the differences in gradations?
A: Gradation means the size and distribution of the particles in the sieve analysis. We refer to three basic gradations in common terms. More technical specifications can be applied to these common terms as well. The "grits-to-dust" is typically any rock dust with a course fraction in the particle size. The largest particle for our purposes can be passing through a 1/4" screen with the dust included or it can be finer, i.e., 1/8"-0 and finer still. The premium BrixBlend gradation is typically 10 mesh (2mm) to dust with about 50% of this passing 200 mesh screen. The 200 mesh and passing is referred to as the Microfine gradation and the Stone Flours. 200 mesh is .0029" (.074mm), i.e., dust. There can be some small variations within these materials depending on the source and the way the materials are produced. Generally the Microfines will be the finest, the Stone Flours may contain a slightly larger particle, more like flour than pure dust. A Silt gradation is typically a very fine sand with a high fraction of stone flour mixed together. This is generally a damp material derived from pond dredging or dewatered slurries.
Q: How Much Rock Dust Do I Use?
A: Application rates will vary according to usage, soil type and condition. Field trials indicate that a direct benefit exists between application rate and increase harvest weight starting at very low rates and running up through very high rates, up to 250% increase in harvest weight over the controls. (Goreau et. al, New Harmony Farm 2012) Rock dust for remineralization has traditionally been utilized at very high rates, up to 10 tons per acre. However the science indicates that low rates of high value rock dust containing a highly micronized fraction will have immediate and lasting benefits. With this in mind, usage protocols can be built around management practice, economics, size of growing area, type of crop etc. For professional soil management practices use of soil tests, careful analysis of rock dust geochemistry and mineralogy, identifying 'limiting factors' in current growing practices and a careful comparison of available rock dusts for targeted use and annual usage rates can provide measurable benefits.
For a less scientific approach, a liberal application of the BEST rock dust in a suitable gradation works. The risk of 'burning' or damaging crops within maximum application rates is virtually nil.
General rules of thumb can help determine application rates. There are 43,560 square feet/acre. If your application rate is 1 ton/acre you will use 5 lbs/100 square feet. Limitations will be determined by soil pH, organic matter in soil and spreading capacity. Choice of particle size, specific geologic make up, proximity of the source and your volume requirements will also determine annual usage and actual rock dust material used in bulk applications.
Here are some general guidelines: In tillage for remineralization purposes; Between 5 and 10 tons/acre of a course stone dust passing (1/4" screen to dust) have been used to advantage. That converts to 25 - 50 lbs material/ 100 square feet in tillage. There is no harm in using less, the results will be determined by the interaction of the rock dusts with the soil media. The highly micronized gradations will work faster as the surface area is greater/ lb. of material. So application rates can be less in the first year to achieve the same growth response. The BrixBlend gradation was formulated to optimize both mechanical attributes of the larger particle with the larger surface area of the micronized material for use in growing media, soils or soil-less. Field research has shown that "the more you use the better" right up to very high application rates (20 tons/acre) before the direct correlation between application rate and yields diverge. See the New Harmony Farm test results for this data on the Home page. For professionals, we recommend working the materials into your management and budget allowances, and use enough material to take advantage of that potential in year one. This will improve your bottom line and may give you some room for adopting more intensive biologic methods, which will optimize both nutritional content and profitability. In some states regulations will limit the amount of material that can be applied in a given year based on metal concentrations in fertilizers or soil amendments. Research with silicate rock dusts indicates that 'availability' and mobility of mineral complexes is governed largely by 'weathering', i.e. mechanical and chemical action of the soil environment and biological activity of soil biota. As such mineral complexes are very stabile in the soil matrix especially within normal pH parameters. For the agronomist the certified geochemical analysis provided with each material can be used as a baseline reference for determining application rates in a given year. We can help design your management strategy based on your parameters.
For direct to ground top dressing of hay land, lawn or turf; 2 - 5 tons/acre of a 50% micronized material can be utilized (100% passing 2 mm screen and 50%+ passing 200 mesh screen such as the Pioneer Valley Basalt "BrixBlend") That converts to 10 - 25 lbs/ 100 square feet.
For maintaining foundation fertility after initial remineralization; Very low rate foliar applications or fertigation of 5-25 lbs/acre of the highly micronized gradations will provide nutrient and energy loads once or more times per season. 1 - 2 tons/acre can be used as a top dressing or incorporated during tillage every 1 to 3 years depending on production and crop rotation. That converts to 5 - 10 lbs./100 square feet. Seven year rotation cycles can also be integrated with rock dust applications over fallowed ground.
We strongly recommend the use of aqueous solutions of micronized minerals and inoculants for foliar, fertigation and drenching during the growing season. The rock dust minerals in
direct-to-ground applications provide the foundation of fertility upon which good intensive nutrient dense management practices rest. Need help with this? Contact us. We're here to help.
Q: When is the best time of year to apply rock dust?
A: Spring tillage is traditional but fall applications can be even better. Apply rock dust powders with other amendments at the same time. Fall tillage or top dressing applications are also excellent as the rock dust incorporated in the fall assimilates over the winter and is available during the spring growing season. I.e., Apply with planting of overwintering tubers such as garlic, broadcast over hay land, or pasture. Rock dust can be applied whenever cover crops are tilled in preparation for new plantings. The charge of micronized minerals will stimulate microbial populations and make the nutrients more available to the new crop. Micronized rock powders can be suspended in water for 'fertigation' and foliar use during the growing season. Top dressing or side dressing can also be done during the season at any time.
Q: How do I spread rock dust?
A: Pulverized rock powders can be spread in traditional lime drill drop spreaders with large openings in the trough. Any damp lime spreader wagon or truck mounted sand and salt spreader will spread any gradation of rock dust except the dry stone flours or "Microfines". The grits-to-dust gradations can be spread like lime, in live floor lime spreaders and augur driven applicators. Microfines and Stone flours can be entrained in water for foliar or fertigation applications or to create slurries and conveyed using diaphragm or rotor-stator pumps. Rock dust can also be added to manure spreaders on top of the load. Please note: Pulverized rock powders will not spread in cone type three point hitch setups. These require granulated or pelleted materials. Caution! Rock dusts often contain silica. Dry stone powders present a breathing hazard. Wear suitable respirators and limit exposure.
Spreading methods by gradation:
Grits-to-dust are suitable for broadcast in live bottom spreaders, wet or damp lime spreaders large drop spreaders, sand and salt type spreaders, or by hand. Stone flours can be spread in drop spreaders or by hand, or pumped in suspensions. Silt gradations can be spread in live bottom wet or damp lime spreaders, sand and salt type spreaders or by hand.
Q: Can I use rock dust in making compost?
A: Yes! Good results have been achieved using 20-25lbs micronized high silica, calcium rich rock dusts/ cubic yard of compost raw material. (We ship the Basalt Microfines and the Ruby Mountain 'True Stone Flour' for this purpose.) You can mix these different geologic sources together to take advantage of each, or use them undivided. This is an excellent way to assimilate the minerals within the biologic system in the soils, making the nutrients available to the plants. Rock Dust Local strongly recommends building compost with the BEST* micronized rock powders as well as blending rock dusts of courser gradation to finished compost material. True Remineralized compost will be built with rock (not just mixed with it post digestion). There is a difference!
Q: How does rock dust compare to conventional synthetic fertilizers?
A: There is little comparison. Many synthetic petroleum derived fertilizers are acid salts or soluble sulfates of a very narrow elemental spectrum, often containing a single elemental nutrient in combination with Chlorine or Sulfur. Chemical fertilizers are usually a combination of
three elements; N, P, and K (Nitrogen, Phosphorus and Potassium) delivered in soluble form. The broad elemental spectrum rock dusts contain a naturally occurring distribution of macro and micro nutrients delivered in mineral form, are generally insoluble crystaline structure and rely on weathering and an active soil biology consisting of beneficial bacteria and fungi to assimilate the mineral elements, making the nutrients available to the plants as needed.Highly micronized fractions of rock dust blends are immediately available to biologic systems and are highly effective in building amino acids and enzymes critical for biologic systems. There is little or no nitrogen in most rock dust materials although essential elements for fixing nitrogen in soils such as Molybdenum and Vanadium are present in many high quality rock dusts. The use of fixed carbon and humic sources are encouraged as companion materials to the broad elemental spectrum rock dusts to help build soil biology and regulate the uptake of essential nutrients in plants. Soil remineralization is a method of encouraging a natural, sustainable and self regulating growing environment which promotes long term and sustainable fertility.
Q: Is there any way to measure the effectiveness of rock dusts?
A: Yes. Annual soil testing should show improvements in both available nutrients and overall nutrient density in soils. Additionally, Brix meter readings should improve, indicating higher sugar and mineral content in plants. Tissue analysis of produce and forage should indicate increased mineral and nutrient value. Overall improvement in plant vigor should follow the assimilation of minerals in the rock dust.
Q: Do I still need to use fertilizers when I apply rock dusts?
A: Initially soils which are seriously depleted of certain mineral nutrients and microbial populations will need to be restored with a combination of macro and micro nutrients, inoculants and fixed carbon sources in addition to the broad elemental spectrum rock dusts. Thereafter, a reliance on the narrow elemental spectrum fertilizer inputs may diminish with good management, crop rotations, adequate use of humic materials, fixed carbon and applications of broad elemental spectrum rock dusts. Most rock dust materials cannot be considered fertilizers in the conventional definition of high soluble doses of N-P-K. These major nutrients will still need to be managed whatever practice is being employed. Rock dusts for remineralization are used to establish a foundation of fertility that good nutrient management rests upon. See resource links on the home page for more information.
MORE INFORMATION and INTERVIEWS WITH THOMAS VANACORE (founder Rock Dust Local):
View John Kohler's Growing Your Greens Videos! And if you wish to purchase packaged rock dust go to the web store>
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