CULTIVATION METHODS ON A PLOT FOR ANNUAL CULTIVATION PLANTS

Description

TECHNICAL FIELD TO WHICH THE INVENTION RELATES

[0001] The present invention relates to techniques for growing annual crops, advantageously so-called sales crops or cash crops. CA 1335434C discloses a method of growing annual crops on a plot. TECHNOLOGICAL BACKGROUND

[0002] The optimum yield of annual crops, advantageously cash crops or cash crops, is currently sought by respecting certain cultural practices which mainly concern: sowing, weeding, protection against bio-aggressors and fertilization.

[0003] To contribute to this optimal productivity, it is also possible to rely on a technique consisting of cultivating these crops in association with plants known as "cover crops".

[0004] This approach, commonly referred to as “associated cultivation”, aims to: to generate a significant biomass, capable of smothering weeds, without however penalizing the development of crop plants, to allow an improvement in the structure of the soil from the moment of planting, and to ensure a supply of nitrogen, to ultimately optimize the yield of crop plants.

[0005] To further contribute to this optimal productivity, it may be interesting to use the phenomenon of "mycorrhiza" produced by mycorrhizal fungi in the soil, that is to say a non-pathogenic symbiosis between certain fungi and the roots of various plants.

[0006] Mycorrhizal fungi are symbiotic fungi of plants, normally present naturally in soils.

[0007] Mycorrhiza stimulates plant growth, especially in poor soils, because the fungal mycelium retains moisture longer and therefore allows for better absorption of water and nutrients by the roots. In return, the fungus removes the various carbon elements it needs from the plant.

[0008] This mycorrhizal fungus is thus intended to inoculate the root system of the plant during its development on the cultivation plot, with a view to improving its development, its resistance to stress, etc. and therefore its yield.

[0009] However, the development of certain agricultural practices (soil work, pesticides, chemical fertilizers) has significantly contributed to the decline, or even the eradication, of these micro-organisms.

[0010] It is then possible to report a mycorrhizal fungus either on the seeds of annual crop plants, or in fertilizers (particularly organic ones).

[0011] However, the positive effects of mycorrhization are not optimal due to the time required for the development and establishment of the mycorrhizal fungus, and in particular its mycelia, in the soil of the plot.

[0012] The cost of this technique is higher today, given the quantities of mycorrhizal fungi required to obtain a significant effect.

[0013] It is therefore interesting to have new agronomic techniques that are capable of further improving the yield of such annual crops and improving the return on investment. SUBJECT OF THE INVENTION

[0014] The present invention relates to a new cultivation method which makes it possible to increase the yield of annual crop plants using rhizospheric microorganisms.

[0015] This cultivation method uses cover crop seeds comprising seeds of at least one legume to which at least one rhizospheric microorganism is applied.

[0016] Cover plants develop on the cultivated plot, and they then assume a “host” role, allowing an increase in the rate of rhizospheric microorganisms in the soil of this plot.

[0017] Annual crops can then be sown on this “mycorrhizal” plot.

[0018] These annual crops are then inoculated more effectively and quickly by rhizospheric microorganisms which have had time to develop and colonize the soil.

[0019] The yield of these crops is thus significantly improved.

[0020] This technique thus allows the creation of conditions favorable to the development of the annual crop plant sown after the plant cover.

[0021] In this case, the invention relates to a method according to the characteristics of claim 1.

[0022] According to other advantageous technical characteristics, which can be taken in combination or independently: said at least one rhizospheric microorganism is chosen from mycorrhizal fungi and / or rhizobacteria (in particular "PGPR" for "Plant Growth Promoting Rhizobacteria"); the cultivation method comprises an operation of applying said at least one rhizospheric microorganism to said cover crop seeds, prior to the operation of sowing cover crop seeds; the cover crop seeds comprise seeds of a single legume variety, or seeds of a mixture of at least two legume varieties, to which said at least one rhizospheric microorganism is applied; said at least one rhizospheric microorganism is chosen from mycorrhizal fungi capable of developing endomycorrhizae with the cover crop plants, preferably mycorrhizal fungi chosen from Glomus intraradices (also called Rhizophagus irregularis); said mycorrhizal fungi, applied to the cover crop seeds, comprise propagules in the form of mycelia, spores or vesicles; the seeds of annual crop plants are chosen from cereal seeds (in particular corn, wheat, barley, sorghum), oilseed and protein crops, market garden crops, industrial crops, protein crops; the operation of sowing cover crop seeds is carried out either during the intercropping period, between two cultivation cycles of annual crop plants, or associated with annual crop plants, or under cover of annual crop plants, of a prior cultivation cycle; the operation of sowing seeds of said annual crop plants is carried out after destruction, or without destruction, of the cover crop plants; the legume seeds of the cover crop are chosen from the genera Trifolium, especially clovers, or Vicia, especially vetch.

[0023] The operation of sowing seeds of annual crop plants is followed by a cultivation cycle (development and harvest) of said annual crop plants. DETAILED DESCRIPTION OF THE INVENTION

[0024] The present invention relates to a novel technique of plant associations which is capable of improving the yield of annual crop plants.

[0025] This new agronomic technique consists of using cover crop seeds, comprising seeds of at least one legume to which at least one rhizospheric microorganism is applied, which are sown on a plot before seeds of the annual crop plant.

[0026] This approach allows the soil to be prepared in order to increase the rate of rhizosphere microorganisms in the soil of the plot and thus optimize the inoculation of annual crop plants subsequently planted. On annual crops

[0027] The present invention applies to the cultivation of annual crop plants.

[0028] By "annual crops" we mean in particular plants for so-called "sales" or "cash" crops.

[0029] Such "annual" cultivation plants include annual plants properly speaking, but also perennial plants.

[0030] These annual crops advantageously include: so-called large-scale crops, in particular cereals and oilseeds, market gardening plants (in greenhouses or in open fields), industrial crops, in particular potatoes, beets, etc., protein crops, in particular peas, field beans, lupins.

[0031] Cereals include in particular corn, wheat, barley, oats and sorghum.

[0032] Oilseeds and protein crops include in particular sunflower, rapeseed, flax and soybeans.

[0033] Market garden crops include potatoes, beans, carrots and beets. On ground cover plants

[0034] The term "plant cover" refers to all plants capable of covering the ground permanently or temporarily.

[0035] These ground cover plants are advantageously chosen from among the “legumes”, that is to say plants of the Fabaceae family or Fabaceae Or Leguminosae.

[0036] Legumes are an ideal vector because they are favorable to the biological life of the soil and to strong mycorrhizal colonizations.

[0037] Among the legumes, plants are advantageously chosen from the subfamily of Faboideae Or Papilionoideae.

[0038] In this last subfamily, the plants are advantageously chosen from the genera: Trifolium, especially clovers; Vicia, especially vetch.

[0039] Cover crop seeds can be used: “pure”, that is to say seeds of a single variety of legume, or “in association”, that is to say comprising the seeds of at least one variety of legume in combination with other complementary species. On the rhizospheric microorganism

[0040] At least one rhizospheric microorganism is applied to these legume seeds.

[0041] This rhizospheric microorganism is chosen from among the "versatile" rhizospheric microorganisms, which are capable of inoculating both cover crop seed plants and annual crop plants, and which are beneficial to the growth and health of these plants.

[0042] By "rhizospheric microorganism" we mean in particular rhizobacteria and / or mycorrhizal fungi.

[0043] Mycorrhizal fungi are advantageously chosen from among mycorrhizal fungi capable of developing endomycorrhizae with the inoculated plants.

[0044] Endomycorrhizae refer in particular to a symbiosis between the root of a plant and fungi, the hyphae of the latter infiltrating the root cells, into the intracellular space.

[0045] Among the mycorrhizal fungi, we particularly choose Glomus intraradices Or Rhizophagus irregularis.

[0046] Rhizobacteria consist in particular of plant growth promoting rhizobacteria or PGPR (Plant Growth Promoting Rhizobacteria) representing a group of bacteria that colonize the rhizosphere and contribute to the good health and growth of inoculated plants.

[0047] By "rhizobacteria" we mean in particular rhizobia, or rhizobia (genus Rhizobium ), that is, aerobic soil bacteria belonging to the family of Rhizobiaceae. These bacteria have the ability to enter into symbiosis with plants of the Fabaceae family by forming nodules.

[0048] Rhizobacteria include bacteria of the genus Bacillus, Pseudomonas Or Rhizobium.

[0049] We can also use: a single species of rhizospheric microorganisms, or a combination of at least two species of rhizospheric microorganisms. On “pre-inoculated” cover crop seeds

[0050] Advantageously, a preliminary operation of applying said at least one rhizospheric microorganism to the plant cover seeds is carried out, prior to sowing the latter.

[0051] For this purpose, rhizospheric microorganisms are applied and fixed to the surface of legume seeds, for example in the form of a film coating or coating of these seeds, or simply by spraying.

[0052] The application of rhizospheric microorganisms to the seeds of the plant cover is carried out using a conventional application technique, for example the application of a solution based on rhizospheric microorganisms presented in powder or liquid form (by spraying, soaking, film-coating, spraying, coating, etc.).

[0053] In the case of mycorrhizal fungi, the rhizosphere microorganism advantageously appears in the form of propagules, that is to say mycelium, spores or vesicles. Cultivation process

[0054] The cultivation method according to the invention comprises different successive operations.

[0055] The “pre-inoculated” cover crop seeds are first sown on the crop plot.

[0056] This operation is carried out in the traditional way, for example using a seeder.

[0057] The cover crop seeds are distributed evenly, or at least almost evenly, over the entire surface of the plot, by sowing in rows or broadcasting.

[0058] This operation of sowing cover crop seeds can be carried out: either during the intercropping period, that is to say between two cultivation cycles of annual crop plants (identical or different), or associated with annual crop plants, or under cover of annual crop plants, during a previous cultivation cycle.

[0059] Cover plants develop and establish themselves, constituting host plants which are inoculated by rhizospheric microorganisms and which allow these rhizospheric microorganisms to develop within the soil of the plot.

[0060] In particular, in the case of mycorrhizal fungi, development leads to the formation of a network of mycelia in the soil.

[0061] This results in an increase in the rate of rhizospheric microorganisms in the soil of the plot, in anticipation of the operation of sowing the seeds of annual crop plants on this same plot.

[0062] By "rhizospheric microorganism levels" we mean in particular: a concentration of microorganisms per mm 3< of the plot soil, or a number of mycelia per mm 3< of the plot soil.

[0063] By "increase in the rate of rhizospheric microorganisms" is meant in particular a quantitative increase in rhizospheric microorganisms in the soil, compared to a soil without prior sowing of "pre-inoculated" cover plants.

[0064] Following a phase of planting plants from cover crop seeds, an operation of sowing seeds of annual crop plants is implemented within this “mycorrhizal” plot.

[0065] This sowing operation is carried out: after destruction of the ground cover plants, or without destruction of the ground cover plants.

[0066] In the case of sowing after destruction, the selected legume plants can be chosen from those which are frost-sensitive (sensitive to frost).

[0067] These plants are thus normally destined to be destroyed naturally, by a period of winter frost.

[0068] It may also be planned to implement a targeted destruction operation of leguminous plants, for example chemical or mechanical destruction.

[0069] By "chemical destruction" we mean in particular the application of a selective herbicide within the plot, to destroy these cover plants but without harming annual crop plants or rhizospheric microorganisms established in the soil.

[0070] The operation of sowing seeds of annual crops is carried out in a conventional manner, while promoting the good survival of rhizospheric microorganisms in the soil.

[0071] In the case of sowing without destruction of the plants in the plant cover, the sowing operation consists of direct sowing of the seeds, directly into the plant cover.

[0072] During the growing cycle, annual crop plants are established on the plot.

[0073] The rhizospheric microorganisms, having previously colonized the soil of the plot, will then quickly and effectively inoculate the root system of the annual crop plants (this advantageously at an acceptable cost).

[0074] In the case of mycorrhizal fungi, these annual crop plants will thus present an improved mycorrhization rate, that is to say advantageously: an improved percentage of mycorrhizal plants, and / or an improved percentage of mycorrhizal roots per plant or per unit length, and / or improved indices of mycorrhization.

[0075] By "enhanced mycorrhization rate" is meant an increased mycorrhization rate with prior sowing of "pre-inoculated" cover plants, compared to cultivation without prior sowing of such "pre-inoculated" cover plants.

[0076] It is possible to quantitatively evaluate this mycorrhization, in particular by: observations of root samples under a magnifying glass or microscope or chemical analyses.

[0077] Annual crops are harvested at the end of the growing cycle, with improved yield. Example

[0078] In the case of an annual crop, for example a rotation between wheat and corn, the "pre-inoculated" cover crop seeds are sown after the wheat harvest (for example August / September).

[0079] The plant cover develops before winter and ensures the development of rhizospheric microorganisms brought back during its growth.

[0080] The plant cover helps to increase the rate of rhizospheric microorganisms in the soil during this inter-crop period.

[0081] The next crop, for example corn, is sown in April / May, most often after destruction of the plant cover in winter or at the end of winter.

[0082] Rhizospheric microorganisms, thus multiplied in the soil during the intercrop, enter into symbiosis with the corn roots more quickly and improve its nutrition. Benefits

[0083] The interest of the technique according to the present invention relates to several aspects: improved mineral nutrition, particularly phosphorus, resistance to biotic and abiotic stress, increased drought resistance, very positive effect on plant growth, protection against pathogenic bacteria and fungi, increased size, increased earliness, improved mycorrhization rate.

[0084] The prior implantation of rhizospheric microorganisms also has the advantage of improving the biological characteristics of the soil with a view to the development of annual crop plants.

Claims

1. Method of growing annual crop plants, preferably a cash crop or a practical use crop, on a plot, said method of growing consisting in implementing at least the following successive actions on the plot: - an action of sowing seeds of a plant cover comprising seeds of at least one leguminous plant to which at least one rhizospheric microorganism is applied, said at least one rhizospheric microorganism being selected amongst the rhizospheric microorganisms that are suitable for inoculating plants which are issued from said seeds for plant cover, and the annual crop plants, - after a phase of planting plants issued from the seeds for plant cover, an action of sowing seeds of said annual crop plants, said plants issued from seeds for plant cover being destroyed naturally, chemically or mechanically, and the annual crop plants being inoculated with said at least one rhizospheric microorganism occupying the ground.

2. Method of growing according to claim 1, characterized in that said at least one rhizospheric microorganism is selected amongst the mycorhizian mushrooms and / or the rhizobacterias.

3. Method of growing according to claim 2, characterized in that said at least one rhizospheric microorganism is selected amongst the mycorhizian mushrooms able to develop endomycorizians with the plants of the plant cover.

4. Method of growing according to anyone of claims 2 or 3, characterized in that the mycorhizian mushrooms are selected amongst Glomus intraradices or Rhizophagus irregularis.

5. Method of growing according to anyone of claims 2 to 4, characterized in that the mycorhizian mushrooms applied to the seeds of the plant cover comprise propagules such as myceliums, spores or vesicles.

6. Method of growing according to anyone of claims 1 to 5, characterized in that it comprises an action of applying said at least one rhizospheric microorganism to the seeds of the plant cover before the action of sowing the seeds of the plant cover.

7. Method of growing according to anyone of claims 1 to 6, characterized in that the seeds of the plant cover comprise: - seeds of a single variety of leguminous plants or - seeds of a mixture of at least two varieties of leguminous plants, on which said at least one rhizospheric microorganism is applied.

8. Method of growing according to anyone of claims 1 to 7, characterized in that the seeds of annual crop plants are selected amongst seeds for cereal crops, oil seeds and protein crops, vegetable crops, industrial crops, and protein crops.

9. Method of growing according to anyone of claims 1 to 8, characterized in that the action of sowing seeds for plant cover is implemented - either during the period between two cultures, between two culture cycles of annual crop plants, - or associated with annual crop plants or together with annual crop plants of a previous crops cycle.

10. Method of growing according to anyone of claims 1 to 9, characterized in that the action of sowing seeds of said annual crop plants is implemented after destroying or without destroying the plants of the plant cover.