Magnesium product for the control of abiotic stress in a culture

Abstract

Magnesium product for controlling abiotic stress in crops. The invention relates to a magnesium product that can be used to control solar abiotic stress in plants. The product comprises a synergistic mixture of two magnesium agents, one with a particle size of less than 10 microns and the other with a particle size of more than 10 microns. Figure for abstract: Fig. 3.

Description

Title of the invention: Magnesium product for controlling abiotic stress in a crop Technical field

[0001] The present invention relates to a magnesium composition which can be used as an agrochemical product for the control of abiotic solar stress in plants. Prior art

[0002] Various solutions have been proposed to combat sunburn on plants. For example, micronized mineral powders combined with active ingredients such as antioxidants, UV filters, or even microorganisms are formulated in suspensions to be applied by foliar application and form a protective film of particles.

[0003] Mineral powders such as kaolin and magnesium carbonate, used for their white color or as UV blocking agents, have thus been proposed as reflective materials to reduce sunburn by blocking the sun's rays.

[0004] In application US20160037772 in particular, a kaolin and a calcium carbonate having a size of the order of 0.5 to 3 microns have been described as a sunscreen in association with 9-oxo-nonanoic acid or arachidonic acid to mitigate the effects of abiotic stress.

[0005] In application WO2009064450 again, the formulation of micronized calcium carbonate in the form of an aqueous suspension was proposed as a sunscreen product.

[0006] White pigments such as titanium dioxide with a particle size of 0.5-2 microns have also been integrated into the polymer matrix of a crop protection net to improve the visible transmittance and increase the UV absorption of the net (US application 20210144932). However, the manufacture of a net is expensive and its installation on crops by the farmer can be tricky.

[0007] It is therefore desirable to reduce the production cost of sun protection solutions and make them easier to apply to crops in order to make farms more profitable.

[0008] There is also a need for a micronized mineral product whose activity in protecting plants against sunburn, and more generally against abiotic stress, is improved. It is thus desirable to reduce the doses of mineral matter required to obtain effective protection, and consequently to reduce bleaching of crops to which the product is applied. product. Statement of the invention

[0009] The present invention responds precisely to these needs by proposing a magnesium agrochemical product in powder form which can be advantageously applied as a film of particles on plant tissues to control the solar abiotic stress to which they are subjected.

[0010] A first subject of the invention thus relates to an agrochemical product in the form of a powder of particles comprising a synergistic mixture of at least one first magnesium agent and at least one second magnesium agent for controlling the abiotic solar stress suffered by a crop.

[0011] The inventors have surprisingly found that the choice of mineral proves to be decisive in effectively combating the phenomenon of burning. Indeed, the level of crop protection can be optimized by increasing the effectiveness of the mineral product.

[0012] The magnesium mineral material of the product of the invention advantageously makes it possible to exercise at least one activity chosen from increasing the level of sun protection of crops, reducing the dose of mineral particles provided to crops with equivalent sun protection, limiting the bleaching of crops, improving photosynthetic activity, and increasing crop productivity.

[0013] In a particular embodiment, the magnesium mineral material of the invention allows the reduction of bleaching of crops with equivalent sun protection and / or the increase in crop productivity.

[0014] The magnesium mineral material of the product of the invention, by its physicochemical characteristics, has a specific behavior in the face of the phenomenon of burning, by a physical interaction with solar radiation including reflection, diffusion, or even absorption of the rays, but also by biological interaction with the plant by supporting the processes of treatment and management of damage linked to these same radiations.

[0015] Taking into account the role that mineral matter can play both physically and biologically, solar protection of crops can thus be optimized to maintain or even increase crop productivity in a context of normal (<1500 kWh / m2 / year) to high (>1500 kWh / m2 / year) radiation exposure.

[0016] The present invention has the effect of limiting the damage induced by the solar radiation spectrum on the plant, by acting on at least one of the following effects: - the reduction of water stress by lowering the surface temperature, thus limiting the use of the evapotranspiration mechanism, a natural regulator of internal temperature of the plant; - optimization of product sizes, increase in SSC (Solid Soluble Content) rates, by maintaining photosynthesis later in intense radiation conditions; - optimizing crop coloration by protecting photosynthetic pigments, by limiting the metabolic impact of oxidative species (ROS) which attack them.

[0017] The contribution of the invention in the fight against these damages helps to maintain, or even increase, the productivity of crops.

[0018] The invention also relates to the use of at least one first magnesium agent and at least one second magnesium agent as described above for controlling solar abiotic stress suffered by plant tissues, preferably chlorophyllous plant tissues.

[0019] Finally, a final object of the invention relates to an agricultural method for applying to a crop an agrochemical product in accordance with the preceding description. Brief description of the drawings

[0020] [Fig. 1] represents the particle size distribution of an agrochemical product magnesium according to the invention.

[0021] [Fig.2] represents the UV-Visible spectral signature of an agrochemical product magnesium according to the invention.

[0022] [Fig.3] represents the evolution of the number of leaves per plant under conditions of artificially generated solar abiotic stress following an application of two magnesium agrochemical products according to the invention in comparison with a product according to the prior art.

[0023] [Fig.4] represents the average percentage of watermelon epidermis affected by the sunburn on a control sample of untreated watermelons, on a sample of crop treated with a product of the prior art and on a sample of crop treated with a magnesium agrochemical product according to the invention.

[0024] [Fig. 5] represents the mass of three watermelon harvests, the first being untreated, the second being treated with a product of the prior art and the third with a magnesium agrochemical product according to the invention.

[0025] [Fig.6] shows the distribution by category of watermelons at harvest on a untreated crop, a crop treated with a product of the prior art and a crop treated with a magnesium agrochemical product according to the invention. Description of the embodiments

[0026] A first object of the invention thus relates to an agrochemical product in the form of a powder of particles comprising a synergistic mixture of at least one first magnesium agent and at least one second magnesium agent for controlling solar abiotic stress suffered by a crop, - the first magnesium agent having a particle size ranging from 10 microns to 110 microns and being a magnesium material comprising at least one compound chosen from magnesium carbonate (MgCO3), dolomite (CaMg(CO3)2), magnesium oxide (MgO), magnesium silicate (MgxSiOy, x and y being decimal numbers), magnesium hydroxide (Mg(OH)2), and their hydrates, and - the second magnesium agent, different from the first magnesium agent, being chosen from: □ a water-soluble magnesium agent selected from magnesium materials comprising at least one compound selected from magnesium sulfate and its hydrates (MgSO4.zH2O, z being an integer), magnesium nitrate and its hydrates (Mg(NO3)2.tH 2O, t being an integer), magnesium chloride and its hydrates (MgCl2.pH2O, p being an integer), and organic magnesium salts selected from magnesium bisglycinate, magnesium citrate, magnesium aspartate, magnesium lactate, magnesium glycerophosphate, magnesium pidolate and magnesium gluconate, and □ a magnesium agent whose particle size is between 0.1 and 10 microns and being a magnesium material comprising at least one compound chosen from magnesium carbonate (MgCO3), dolomite (CaMg(CO3)2), magnesium oxide (MgO), magnesium silicate (MgxSiOyx and y being decimal numbers), magnesium hydroxide (Mg(OH)2), and their hydrates.

[0027] The term "magnesium material" means a material comprising more than 50% by mass, or even more than 80% or more than 90% by mass of a magnesium compound. The magnesium material may be a magnesium material obtained by extraction of an ore followed by grinding and micronization.

[0028] The particle size of the first magnesium agent, also called granulometry, ranges from 10 microns to 150 microns, preferably from 10 microns to 140 microns, from 10 microns to 120 microns or from 10 to 110 microns.

[0029] The particle size of the second magnesium agent is between 0.1 and 10 microns, when it is chosen from magnesium materials comprising at least one compound chosen from magnesium carbonate, dolomite, magnesium oxide, magnesium silicate, magnesium hydroxide or one of their hydrates.

[0030] In the present application, the expression "ranges from ... to ..." to describe a range of value includes the limits, while the expression "between ... and ...." to describe a range of value which excludes the limits.

[0031] The particle size can be determined by mass, number or volume by any method known to those skilled in the art such as sedimentometry or laser diffraction for example, the characteristic size of a particle being for example defined as equal to the diameter of a sphere of the same volume as that of the particle.

[0032] Sedimentometry is based on the evaluation of the settling speed of the particles of the magnesium agent in water. The method uses the absorption of X-rays by the suspension of particles at a given height and a given time.

[0033] The relative distribution of the particle size of the first magnesium agent and the second magnesium agent, also called the particle size distribution of the mixture of the first and second magnesium agents, can be represented in an increasing cumulative mode, by summing the fractions of particles whose size is less than a given value.

[0034] According to a particular embodiment, the particle size distribution of the mixture is such that the first magnesium agent represents between 1 and 99% of the total volume of the mixture, preferably between 60% and 80% of the total volume of the product or the mixture, and the second magnesium agent represents between 1 and 99% of the total volume of the product, preferably between 20% and 40% of the total volume of the product or the mixture.

[0035] The characteristic diameters of the mixture of the two magnesium agents may be D10, D50 or D90 which correspond respectively to 10%, 50% and 90% of the cumulative frequency in number, mass or volume. In one embodiment of the present invention, the synergistic mixture has a particle size ranging from 0.1 to 150 microns. The synergistic mixture may have an average particle diameter D50 of between 5 microns and 40 microns, for example between 10 microns and 20 microns, D50 referring to the median of the particle diameter of the mixture.

[0036] In a particular embodiment, the first magnesium agent is a magnesium material comprising magnesium carbonate, and the second magnesium agent is a magnesium material comprising magnesium carbonate. In this embodiment, the magnesium materials advantageously contain magnesium carbonate in a preponderant amount. The magnesium materials advantageously consist essentially of magnesium carbonate.

[0037] In the present description, “essentially consisting” is understood to mean comprising more than 90% by mass, for example more than 95% or more than 98% by mass.

[0038] The whiteness index may be greater than 60, greater than 70, or preferably greater than 75, the person skilled in the art having at his disposal several methods for measuring the whiteness index which are part of his general knowledge. For example, the whiteness index of the synergistic mixture, measured in the CIE colorimetric system (Woe), may be greater than 60, preferably greater than 75.

[0039] In a particular embodiment, the product of the invention is essentially made up of magnesium materials.

[0040] The agrochemical product of the invention is intended for agricultural use, and more broadly, for the sun protection of plants.

[0041] The agrochemical product may be applied by spraying, misting, powder dispersion, or by any other foliar spraying system, in order to limit the damage caused by solar radiation on the epidermis of plants.

[0042] The agrochemical product of the invention may be formulated in the form of micronized powder, in the form of gelled powder, or in the form of an aqueous suspension to be diluted in a spray tank. It may be applied in the form of a film of active particles in the fight against solar radiation and the support of the biological reactions which result from it.

[0043] In a particular embodiment, the product is applied at a dose ranging from 0.1 kg / ha to 100 kg / ha per application, preferably from 10 kg / ha to 30 kg / ha per application, during periods of exposure to solar radiation during the development of the crop, but also during its storage. The application may take place every day to every month, preferably every 1 to 3 weeks, depending on the weather conditions and the development of the crop. The application will preferably be carried out using a sprayer. The dilution of the material will preferably be 5% to 10% w / w of water.

[0044] The crop may be chosen from market garden crops, for example watermelon, melon, tomato, pepper, eggplant, cucumber, potato or salad, fruit crops, for example apple, pear, vine, apricot, nectarine, peach, lemon, mandarin, orange, olive tree, walnut tree, hazelnut tree, berries, strawberry, cherry, pineapple, banana, avocado, durian, cocoa or oil palm, field crops, for example corn, wheat, barley, sorghum, rapeseed, sugar cane and beetroot, ornamental crops such as flowers, and any other crop that may be affected by the phenomenon of sunburn.

[0045] The invention also relates to the use of at least one first magnesium agent and at least one second magnesium agent as described above for controlling solar abiotic stress suffered by plant tissues, preferably chlorophyllous plant tissues.

[0046] Finally, a final object of the invention relates to an agricultural method for applying to a crop an agrochemical product in accordance with the preceding description. Examples

[0047] - Characteristics of the product of the invention: The agrochemical product comprises 30% by volume of a first magnesium carbonate having a particle size between 0.1 and 10 microns (Agent Mg 1) and 70% by volume of a second magnesium carbonate having a particle size ranging from 10 to 110 microns (Agent Mg 2).

[0048] The whiteness index of the product Agent Mg 1 + Agent Mg 2 is greater than 75 (WCie )•

[0049] The particle size distribution of the product of the invention was determined by sedimentometry using a Malvern Mastersizer V 3.81 device. [Fig. 1] represents the particle size distribution of the agrochemical product, the percentage of a fraction of the volume of the particles on the ordinate, and the maximum size of the fraction on the logarithmic scale on the abscissa.

[0050] The reflection capacity of the product of the invention for ultraviolet and visible radiation was evaluated by obtaining the spectral signature of reflectance using a Jasco spectrophotometer, model V-750. The spectrum obtained is reproduced in [Fig.2]. In the ultraviolet range, in particular UVb (280-315nm), 65% to 70% of the radiation is reflected by the product. In the visible range, in particular in PAR where Chlorophylls a and b act at 430-445 nm and 645-660 nm, 76% and 78% of the radiation is respectively reflected by the product of the invention. Finally, in the near infrared range, starting at 700nm and measured up to 900nm, 70% and 75% of the radiation is respectively reflected. - Greenhouse study (controlled conditions with artificial exposure): Plant material: Tomato plants of the Rose de Berne variety were grown in excess until the fruiting stage in order to select plants with a homogeneous stage of development to begin the trial.

[0051] Materials tested: three micronized mineral powders were evaluated in this test: - An aluminum silicate (kaolin) known in agriculture for its sun protection effect, - a product according to the invention (Product of the invention 1) containing 30% by volume of a calcium carbonate with a particle size between 0.1 and 10 microns (Agent Mg 1) and 70% by volume of a calcium carbonate with a particle size between 10 and 110 microns (Agent Mg 2). - a product according to the invention (Product of the invention 2) comprising a mixture of three magnesium agents including Agent Mg 1, Agent Mg 2 and a magnesium sulfate. Terms and conditions:

[0052] The four modalities are presented in Table 1. [Tables 1] Control Control (untreated) Prior art product Kaolin Product of invention 1 Agent Mg 1 + Agent Mg 2 Product of invention 2 Agent Mg 1 + Agent Mg 2 + magnesium sulfate

[0053]

[0054]

[0055]

[0056] The products were diluted in water at a dose of 5% by mass and sprayed to the point of runoff using a hand sprayer on the leaf surface and fruits. Conditions: After 24 hours, the plants were placed in a growth chamber and exposed to abiotic stress (jO) using lights simulating the solar spectrum containing ultraviolet, visible and infrared radiation. Notations: observations were carried out at d+9 and d+16 in order to assess the number of leaves produced under stress conditions. - Greenhouse study results: The results presented in [Fig.3] show a reduction in the rate of foliar emission with the kaolin modality compared to the control (untreated), this can be explained by a significant coverage of the powder on the leaves thus reducing the photosynthetic activity of the plant which therefore impacts the metabolism of the plant. The contribution of the product of invention 1 alone allows a higher level of vegetative activity than the control, but the growth is further improved by the product of invention 2. - Field study (natural conditions in the area of ​​occurrence): Plant material: The trial was conducted in the field on watermelons of the Nikita variety. Materials tested: Two micronized mineral powders were evaluated in this trial: - a kaolin known in agriculture for its sun protection effect - the product according to the invention described above comprising a mixture of two magnesium agents. Terms and conditions: The three modalities are presented in Table 2. [Tables 2] Control (untreated) - Kaolin 50 kg / ha Product of the invention 1 24 kg / ha Conditions: These treatments are applied using a foliar sprayer during the fruit development, then again when 20% of the fruit has reached maturity.

[0057] Ratings: the percentage of the fruit surface affected by sunburn is assessed at harvest, as well as the weight and class of the fruit according to current standards. - Results: The results are shown in Figures 4, 5 and 6.

[0058] The use of the synergistic mixture of the invention allows a gain in productivity under light stress conditions compared to kaolin, used as a reference. This is explained by the combination of the physical and biological effect of the product of the invention.

[0059] Indeed, [Fig.4] shows the capacity of the product of the invention to reduce the phenomenon of sunburn by 60% compared to the untreated control.

[0060] In addition, the evaluation of the category of fruits linked to their level of aesthetic quality ([Fig.5]), as well as the measurement of the weight of the fruits ([Fig.6]) shows the impact of the product of the invention on the productivity of the crop. These results show that the product of the invention allowed a gain of +7% of the weight of the watermelon equivalent to +185g per fruit, in comparison with the untreated control, and +162g compared to kaolin. Similarly, the evaluation of the category of fruits ([Fig.5]) shows an improvement in the quality of the fruits produced with +13% in Class 1 compared to the untreated control, thus fruits in Class 2, less profitable, were able to achieve better quality thanks to the application of the product of the invention.

Claims

Claims

1. Agrochemical product in the form of a powder of particles comprising a synergistic mixture of at least one first magnesium agent and at least one second magnesium agent for controlling abiotic solar stress experienced by a crop, - the first magnesium agent having a particle size ranging from 10 microns to 110 microns and being a magnesium material comprising at least one compound chosen from magnesium carbonate, dolomite, magnesium oxide, magnesium silicate, magnesium hydroxide, and their hydrates, and - the second magnesium agent, different from the first magnesium agent, being chosen from: □ a water-soluble magnesium agent chosen from magnesium materials comprising at least one compound chosen from magnesium sulfate and its hydrates, magnesium nitrate and its hydrates, magnesium chloride and its hydrates, and organic magnesium salts chosen from magnesium bisglycinate,magnesium citrate, magnesium aspartate, magnesium lactate, magnesium glycerophosphate, magnesium pidolate and magnesium gluconate, and □ a magnesium agent whose particle size is between 0.1 and 10 microns and being a magnesium material comprising at least one compound chosen from magnesium carbonate, dolomite, magnesium oxide, magnesium silicate, magnesium hydroxide and their hydrates.,

2. Agrochemical product according to claim 1, characterized in that the whiteness index of the synergistic mixture is greater than 60, preferably greater than 75.

3. Agrochemical product according to claim 1, characterized in that the synergistic mixture has a particle size ranging from 0.1 to 150 microns and a D50 between 5 microns and 40 microns.

4. An agrochemical product according to claim 1, characterized in that the first magnesium agent is a magnesium material comprising magnesium carbonate and the second magnesium agent is a magnesium material comprising magnesium carbonate.

5. Agrochemical product according to claim 1, characterized in that the first magnesium agent represents between 60% and 80% of the total volume of the product, and in that the second magnesium agent represents between 20% and 40% of the total volume of the product.

6. Agrochemical product according to claim 1, characterized in that it consists essentially of magnesium materials.

7. Use of the combination of at least one first magnesium agent and at least one second magnesium agent according to one of the preceding claims for controlling solar abiotic stress suffered by plant tissues.

8. Agricultural method of applying to a crop an agrochemical product according to one of claims 1 to 7.

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