Nature-based soil enhancing mixture

Abstract

The invention relates to a nature-based soil enhancing mixture comprising besides volcanic rock dust, arbuscular mycorrhizal fungi, clay minerals and organic matter infused with microbial life like actinomycetes. Furthermore, this mixture essentially consists of mica's, and feldspar or hornblende or both feldspar and hornblende. The organic matter is preferably vermicompost. The invention also offers the application of this mixture to improve the soil by enhanced weathering for healthy flora and storage of CO2.

Description

[0001] Nature-based soil enhancing mixture

[0002] The invention relates to a nature-based soil enhancing mixture comprising volcanic rock dust, arbuscular mycorrhizal fungi, clay minerals and organic matter infused with microbial life. The invention further relates to an application thereof to improve the soil.

[0003] Depleted soils occur worldwide due to long-term soil mismanagement like mass production, monoculture, decades of using chemical fertilizers, acidification of the soil, poor soil life and structure. Without enough nutrients by mass production, the soil will lose its Cation Exchange Capacity (CEC). This is the capacity of the soil to hold nutrients and water. Depleted soils with their poor and loose soil structure easily get blown away e.g. by dust storm or lose more nutrients by leaching and erosion. Desertification is the result. The Dust Bowl of 1935 is a clear example, see https: / / drought.unl.edu / dustbowl.

[0004] When large-scale areas produce only one type of plant, also called monoculture, the soil depletes rapidly. This is caused on one hand by the singular type of extraction of nutrients from the soil and the basic chemical Nitrogenous Phosphorous Potassium (NPK) fertilizers. On the other hand, flora and soil life cannot live in symbiosis simply due to the fact there are too little different elements in the soil to create a stable environment. Furthermore, today's consumers are very critical of the appearance and shape of fruit and vegetables. As a result, crops are not resilient enough to fight pests, so the need for pesticides increases.

[0005] Using chemical NPK fertilizers is similar to injecting salt straight into the soil resulting in acidified soils. These fertilizers have the same effect on soil life as salt on a snail. It causes a lot of stress for soil life and counteracts symbiosis. They are crucial to process the needed minerals and making them available for the flora. When soil life gets stressed or even disappears biodiversity is automatically declining, biodiversity and healthy soil life are inextricably linked and crucial for a healthy earth.

[0006] Soil life in stressed condition due to the lack of an unbalanced nutrient sufficiency becomes overactive, which means that they can eat up to 80% of all organic matter within one year. This means more nutrients are made available for flora than needed and the capacity of the soil to hold those nutrients or water declines, with leaching as a result. Carbon dioxide (CO2) is extracted from the air through rain drops which settle on the ground; a healthy soil captures this CO2 and stores it. An unhealthy soil means a deteriorated absorption of CO2 and can result in a release of the CO2 and other greenhouse gasses already detained by the soil.

[0007] An important solution is the Enhanced Weathering process that aims to accelerate the natural weathering by spreading finely ground silicate rock onto surfaces which speeds up chemical reactions between rocks, soil and rain, see E. E. M. te Pas, M. Hagens and R. N. J. Comans, Soil Chemistry and Chemical Soil Quality, https: / / edepot.wur.nl / 587360. It also removes CO2 from the air, permanently storing it in solid calcium carbonate minerals as described by Goll, D.S., Ciais, P., Amann, T. et al. Nat. Geosci. 14, 545-549 (2021). https: / / doi.org / 10.1038 / s41561-021-00798-x. In an article published in Plants, People, Planet, volume 3, issue 5 (2021), Verbruggen et al. suggested that mycorrhizal fungi may critically contribute to enhanced weathering by rock dust in agricultural systems. However, it has been indicated in this article as well that experiments to really prove the contribution of the mycorrhizal fungi to the success of enhanced weathering are still needed. US 2019 / 0256431 (DI) describes broadly a lot of bioavailable fertilizer compositions comprising amongst others gravel dust, basalt powder, bentonite clay, mica, without specifically disclosing any preferable compositions.

[0008] The present invention has for its object to provide a mixture with still better properties to accomplish healthy water, flora and air. In order to achieve the stated object the invention provides a soil improvement mixture as stated in the preamble, characterized in that the volcanic rock dust, besides the arbuscular mycorrhizal fungi, clay minerals and organic matter infused with microbial life, has a grain size range from 60 pm to 2000 pm and essentially consists of feldspar or hornblende micas

[0009] Fe < 15 wt %

[0010] Ca > 5 wt %

[0011] Mg > 3 wt %

[0012] Si > 30 wt % - < 63 wt %.

[0013] In a preferred embodiment the mixture according to the invention comprises hornblende besides feldspar, viz both feldspar and hornblende. Furthermore, the organic matter is preferably vermicompost, especially with a C / N (carbon / nitrogen) ratio of 5 - 30, especially of 10 - 20, at a pH value of 5 - 8, especially of 6 - 7. In case of shortage of vermicompost it may partially be replaced by other types of compost provided that the vermicompost is at least 30% of the organic matter. Preferably, microbial life comprises actinomycetes.

[0014] Preferably, the clay minerals comprise for 65 - 75 wt %, especially for 70 wt % of dry substance and preferably for 3 - 20 wt % , especially for 6 - 10 wt % of organic matter, preferably at an electrical conductivity (EC) value < 10 mS / cm, especially < 7 mS / cm and preferably at a pH value of 5 - 9, especially of 6 - 8. A supplement like zeolite, bentonite and glauconite may advantageously be added to the clay minerals as well.

[0015] Another aspect of the invention provides the application of the mixture according to the invention to improve the soil by enhanced weathering for healthy water, flora and air. Application of this mixture will advantageously limit global warming in accordance with the climate goals set by The Paris Agreement / UNFCCC of 2015 with a circular product that stimulates the long-term sequestration of CO2 and other greenhouse gases in the soil. Furthermore, the mixture according to the invention may be applied universally, for enhancing both uncultivated and cultivated soil and growing various crops.

[0016] The mixture according to the invention is a 100% natural mix made from waste or residual flows to accomplish a healthier soil and ecosystem. All three components (rock dust, clay minerals and organic matter) are preferably mixed on a ratio of about 1 / 1 / 1 by weight and the mixture is preferably sprayed lightly with vermicompost tea.

[0017] This mixture is based on ingredients which represent three basis aspects of the soil: chemical, physical and biological aspects.

[0018] - For the chemical part volcanic rock dust is applied,

[0019] - for the physical part fertile clay minerals form the basis for an optimal soil structure, which already retains water and minerals; furthermore, it already forms a steady basis of nutrients for flora to grow,

[0020] - for the biological part organic matter filled with microbial life is added, vermicompost tea (VCT) is preferably selected for accelerating soil symbioses and speeding up the enhanced weathering process. It also can be adjusted for specific crops or regions / climates. Microbial life is an important player in keeping the soil healthy and making minerals and trace elements available for flora. It exchanges these for sugars produced by the flora through photosynthesis, the process in which flora take upon CO2 from the atmosphere. Microbial life in the mixture according to the invention comprises for instance actinomycetes. Actinomycetes are aerobic, spore forming gram-positive bacteria, belonging to the order actinomycetales characterized with substrate and aerial mycelium growth. They are the most abundant organisms that form thread-like filaments in the soil and are responsible for characteristically “earthy” smell of freshly turned healthy soil. They play major roles in the cycling of organic matter; inhibit the growth of several plant pathogens in the rhizosphere and decompose complex mixtures of polymer in dead plant, animal and fungal material results in production of many extracellular enzymes which are conductive to crop production. The major contribution in biological buffering of soils, biological control of soil environments by nitrogen fixation and degradation of high molecular weight compounds like hydrocarbons in the polluted soils are remarkable characteristics of actinomycetes. Besides this, they are known to improve the availability of nutrients, minerals, enhance the production of metabolites and promote plant growth regulators. Furthermore, actinobacteria do not contaminate the environment instead, they help sustainably in improving soil health by formation and stabilization of compost piles, formation of stable humus and combine with other soil microorganisms in breaking down the tough plant residues such as cellulose and animal residues to maintain the biotic equilibrium of soil by cooperating with nutrient cycling (Microbial Pathogenesis, Volume 111, October 2017, Pages 458- 467).

[0021] A healthy soil means a symbiosis between soil, soil life and flora so that flora can develop better, growing bigger and stronger. This means that flora becomes more resilient against stress, diseases and pests. Due to the bigger stems, flora are able to transport more juices through the plant body, containing more minerals and vitamins. This all results in a higher growth rate, higher yield rate and more importantly: healthier flora and thus food, and a more effective way of sequestering of CO2.

[0022] As elaborated above, the mixture of the invention comprises volcanic rock dust blended with fertile clay-minerals and organic matter, infused with microbial life. This mix is based on the biological, physical and chemical aspects of the soil. It brings back the needed levels of healthy minerals, nutrients and trace elements into the soil, without disturbing the natural ecosystems. It minimizes the usage of chemical fertilizers, herbicides and pesticides used in agriculture. The mixture according to the invention is made of rest / waste materials and is based on the three natural cycles on earth: the water cycle, the nitrogen cycle and the carbon cycle.

[0023] The process starts with the carbon cycle. The movement of carbon from the atmosphere to the rocks in the lithosphere begins with rain. Atmospheric carbon (CO2) and water (H2O) form a weak acid: carbonic acid (H2CO3) which falls onto rocks when it rains and this acid dissolves them. This is a natural process called chemical weathering. When silicate rocks are as small as nano particles, the reactive surface area increases massively, and the chemical weathering process is accelerated. This is called enhanced chemical weathering. The mixture according to the invention contains these silicate nano particles and thus results in this enhanced weathering process, to absorb extra CO2 from the atmosphere through rain drops.

[0024] Said rock dust contains, among others, elements like magnesium, calcium, and silicium. When the acid rain comes in contact with said rock dust the so-called enhanced weathering process starts. Elements like magnesium and calcium are released from the silicates and dissolved in water as it moves through the soil. The minerals in the soil react with the water and carbon, that would otherwise return into the atmosphere, forming bicarbonates (HCO3') remaining in water for thousands of years and eventually find their way to the oceans where they precipitate out as limestone and stay on the seafloor for millions of years. Besides the minerals and trace elements, the rock dust contains glimmers or micas. The chemical weathering process changes these glimmers or micas into fresh clay plates which help to create an optimal soil structure: the clay plates with its net negative charge function as a sort of ‘glue’, connecting and exchanging all minerals and trace elements.

[0025] The clay minerals in the mixture according to the invention give a better structure and hold clay plates. The small size and their distinctive flat structure make clay minerals very special with their unique properties including high cation exchange capacity, swelling behaviour, specific surface area and adsorption capacity. Minerals are protected in this way from leaching and erosion, forming a steady basis and natural nutrient reserve.

[0026] The organic matter is selected to represent humus in the soil with its nutrient value, microbial activity and a specific C / N ratio. It is able to provide soil life the food and energy it needs. It ensures the best structure and water permeability. This mixture is infused with specific soil life to accelerate the enhanced weathering process, an important part making the mixture according to the invention surprisingly effective. The benefits of using rock dust in the agriculture is well known, but the addition of microbial life such as vermicompost is new. By applying the mixture according to the invention, the capacity to hold nutrients on agricultural land, or any other piece of soil, is increased in this way more quickly, and more CO2 is sequestered and stored than by only using the rock dust with fungi.

[0027] In the mixture according to the invention bigger and smaller particle sizes of the rock dust are used creating different sized pores through which water and air can easily find their way. The crystal molecular structure of the rock dust makes it easy to bind organic matter, clay, silt, and sand together. With active soil life working the soil it all leads to a healthy and very stable clay-humus complex and therefore ensures an optimal CEC and storage of nutrients for the longer term.

[0028] By using natural products and working with nature the soil is provided with the total palette of elements it should consist of. By doing so the mixture according to the invention remineralizes the soil restoring long lost nutrients which were lost due to decades of extraction of nutrients and use of one-sided chemical fertilizers, pesticides and desertification. Finally, the mixture is unique because it is:

[0029] 100% natural; made with residual flow materials; powered by the natural cycles and processes of the earth; a unique combination of rock dust with clay minerals and organic matter like for instance vermicompost: it focuses on all three aspects of the soil, to optimizing all these three aspects; contains specifically researched and selected microbial life (comprising: aerobic microorganisms from VCT), which has a positive effect on the speed and the benefits of the enhanced weathering process; and can be customized for specific crops or soil type by adjusting the volumes in the mix or by adding specific natural supplements e.g., like Epsom salt for a boost off magnesium and sulphur or a special customised VCT from the flora and fruits of the local region or a specific fruit or plant type.

[0030] In the present application a value as indicated stands for a range of plus or minus 10%. For instance: for 6 - 8 stands for: 5,4 - 8,8. Furthermore, clay minerals refer to a group of hydrous aluminosilicates that predominate the clay-sized (2 pm) fractions of soils. These minerals are similar in chemical and structural composition to the primary minerals that originate from the Earth's crust; however, transformations in the geometric arrangement of atoms and ions within their structures occur due to weathering. Rock dust is a by-product of quarry work and is generally a finely pulverized material that resembles silt. Soil life comprises of a large number of different organisms, such as fungi, bacteria, mites, nematodes, pot worms and earthworms.

[0031] The invention is further elucidated based on the following examples.

[0032] Example 1. Application of the mixture according to the invention on eroded soil

[0033] A trial has been executed at the High Tech Campus Eindhoven (The Netherlands) on a grass court that is used for recreative use and sports like soccer and cricket. The soil type is sandy soil. The application of a mix with composition of one part rock dust, one part of clay minerals and one part of organic matter at a rate of ten tons per hectare has been applied with a hand driven sand spreader. After the application two soil samples have been taken with a time interval of three months and the analysis has been done by Eurofins, Agro Testing BV, Wageningen, the Netherlands. The soil samples have been taken by the inventor with a ground drill following the standard instructions for taking a soil sample.

[0034] Composition of eroded soil without application of the mixture according to the invention (after a period of three months):

[0035] Unit Result

[0036] Clay (<2 pm) % < 1

[0037] Silt (2-50 pm) % 8

[0038] Sand (>50 pm) % 90

[0039] Clay-humus (CEC) mmol + / kg 24

[0040] CEC saturation % 100

[0041] Ca saturation % 83

[0042] Mg saturation % 19

[0043] K saturation % < 0.1

[0044] Na saturation % < 0.1 Unit Result

[0045] H saturation % < 0.1

[0046] Al saturation % < 0.1

[0047] Composition of eroded soil with application of the mixture according to the invention (after a period of three months).

[0048] Unit Result

[0049] Clay (<2 pm) % <1

[0050] Silt (2-50 pm) % 9

[0051] Sand (>50 pm) % 89

[0052] Clay-humus (CEC) mmol + / kg 29

[0053] CEC saturation % 100

[0054] Ca saturation % 76

[0055] Mg saturation % 20

[0056] K saturation % 4,8

[0057] Na saturation % < 0.1

[0058] H saturation % < 0.1

[0059] Al saturation % < 0.1

[0060] Water retaining capacity and microbial biomass of the depleted soil:

[0061] Unit Result

[0062] Moisture retention capacity mm 15

[0063] Microbial biomass mg C / kg 328

[0064] Microbial activity mg N / kg 63

[0065] Fungal / bacterial ratio 0.8 Water retaining capacity and microbial biomass of the depleted soil after application of the mixture according to the invention during three months:

[0066] Unit Result

[0067] Moisture retention capacity mm 16

[0068] Microbial biomass mg C / kg 446

[0069] Microbial activity mg N / kg 66

[0070] Fungal / bacterial ratio 1.8

[0071] It has thus been found that upon application of the mixture according to the invention during a period of three months the composition of the soil has improved a lot when it comes to percentages of clay, clay-humus and to structure. Also the water retaining capacity and microbial biomass have increased significantly.

[0072] Example 2. Growing bok choy on soil treated with the mixture according to the invention versus soil usual for this type of crop

[0073] The test was executed in a greenhouse under controlled conditions during a period of six weeks. Prior to planting, the biological grower had prepared the soil with a specific usual mixture for growing bok choy.

[0074] The following two applications of the invention have been mixed in the soil (surface per group 1 m2):

[0075] Group 1) 500 gram of mixture according to the invention with the composition of one part rock dust, one part clay minerals and one part organic matter

[0076] Group 2) 1 kilogram of mixture according to the invention with the same composition as group 1

[0077] The plants were planted in week 41 and harvested in week 47 with a planting density of sixteen plants per m2. After harvest, ten plants per application have been weighed and compared with the plants from the non-treated soil. The advantageous results of the application of the mixture according to the invention were as follows: thinner main roots which means it costs less energy to stand more hair roots, which means a higher capacity for absorption of nutrients and spore elements shorter tap root which means that the plant has to take less effort to reach its nutrients on average 18% extra weight per plant.

[0078] See figure 1: Bok choy at the left side: grown on soil treated with the mixture according to the invention from group 1 versus at the right side: grown on soil usual for this type of crop.

[0079] See figure 2: Bok choy group 1 with mixture versus grown on usual soil for this type of crop without mixture.

[0080] In conclusion:

[0081] The mixture according to the invention has surprisingly effective properties in improving the properties of soil and therewith of the crops growing on it. Besides that, the mixture only consists of natural elements. Although the invention has been elucidated above with reference to a number of applications of a mixture comprising rock dust, clay minerals and organic matter infused with microbial life, it will be apparent that the invention is by no means limited thereto. On the contrary, many variations are possible within the scope of the invention for a person with ordinary skill in the art.

Claims

Claims1. Nature-based soil enhancing mixture comprising volcanic rock dust, arbuscular mycorrhizal fungi, clay minerals and organic matter infused with microbial life, wherein the rock dust has a grain size range from 60 pm to 2000 pm and essentially consists of: feldspar or hornblende micasFe < 15 wt %Ca > 5 wt %Mg > 3 wt %Si > 3 wt % - < 63 wt %.

2. Mixture according to claim 1 wherein the rock dust essentially consists of hornblende besides feldspar.

3. Mixture according to claim 1 or 2 characterized in that the organic matter is vermicompost.

4. Mixture according to claim 3 characterized in that the vermicompost comprises a C / N ratio of 5 - 30 at a pH value of 5 - 8.

5. Mixture according to any one of the claims 1 - 4 characterized in that the clay minerals comprise for about 65 - 75 wt % dry substance and for 3 - 20 wt % organic matter, at an EC value < 10 mS / cm and a pH value of 5 - 9.

6. Application of the mixture according to any one of the claims 1 - 5 to improve the soil by enhanced weathering for healthy flora and storage of CO2.

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