CONCENTRATED EXTRACT OF ALGAE, PRODUCTION METHOD THEREOF AND USE OF SAME IN AGRICULTURE

Abstract

The present invention relates to a concentrated algal extract having a percentage dry matter of between 6 and 100%, the preparation process thereof and also the uses thereof alone or combined with another nutritive, biostimulating or plant-protecting technology, especially to promote plant emergence, growth, development and reproduction and to prevent birds from eating the seeds. The invention also targets a process for applying the concentrated algal extract of the present invention, and also a seed coated with said extract.

Claims

1. A process for preparing a concentrated algal extract, the concentrated algal extract having a percentage dry matter of between 6 and 100%, and containing 0 to 5%, by weight of alginate or of cellulose relative to the weight of said extract, the method comprising grinding the algae until the cells rupture; homogenizing the ground algal material in aqueous solution; removing the alginate and the cellulose from the homogenate by flocculation and filtration; concentrating the filtrate to reach a percentage dry matter of between 6 and 100%, preferably between 9 and 70%, more preferentially between 12 and 50%.

2. The method of claim 1, wherein the percentage of dry matter is between 9 and 70%.

3. The method of claim 1, wherein the percentage of dry matter is between 12 and 50%.

4. The method of claim 1, wherein the algae is Ascophyllum nodosum, Fucus vesiculosus, Laminaria digitate, Laminaria hyperborea, Laminaria saccharine, Eklonia maxima, Sargassum spp, or a mixture thereof.

5. The method of claim 1, wherein the extract has a pH of 1.5 to 9.

6. The method of claim 1, wherein the extract has a pH of 2 to 7.

7. The method of claim 1, wherein the extract has a pH of 2.5 to 3.

8. The method of claim 1, wherein the step of concentrating the filtrate is performed by reverse osmosis, by water evaporation, by algae enrichment or by centrifugation.

9. The method of claim 1, wherein the percentage of dry matter of said extract is between 9 and 70%, and said extract contains 1 to 4% by weight of alginate and cellulose relative to the weight of said extract.

10. The method of claim 1, wherein the percentage of dry matter of said extract is between 12 and 50%, and said extract contains 2 to 3% by weight of alginate and cellulose relative to the weight of said extract.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0061] FIG. 1 is a schematic representation of the number of corn seedlings obtained 3 weeks after sewing uncoated corn seeds, corn seeds coated with an algal extract of the present invention or corn seeds coated with a conventional fungicide as described in example 4.

[0062] FIG. 2 is a schematic representation of the number of corn seedlings obtained 3 weeks after sewing uncoated corn seeds, corn seeds coated with an algal extract of the present invention or corn seeds coated with a conventional fungicide as described in example 5.

EXAMPLES

Example 1: Preparation of a Concentrated Algal Extract

[0063] An extract of Ascophyllum nodosum algae having a percentage dry matter of 5.1%, denoted GOACTIV by the applicant company, is concentrated by water evaporation by heating the extract at 50° C. in a rotary evaporator under (water-pump) vacuum until the percentage dry matter reaches 13%.

Example 2: Application of the Concentrated Algal Extract to Tomato Seedlings

[0064] An amount of extract per plant as indicated in the table below is sprayed once a week onto the leaves of tomato seedlings at the 3-leaf stage (3 weeks):

TABLE-US-00001 Comparative: According to the invention Algal extract GOACTIV (example 1) % dry matter 5.1% 13% Amount of extract 0.03 mg 0.01 mg sprayed per seedling

[0065] The tomato seedlings are thus treated with comparable amounts of each extract. After 5 weeks of treatment, the tomato seedlings treated with the concentrated algal extract of the present invention (example 1) are taller and bushier than the seedlings treated with the non-concentrated algal extract (GOACTIV).

[0066] For comparable amounts of extract applied, the concentrated algal extract of the present invention is therefore more effective at promoting the growth of tomato seedlings than a more diluted extract.

Example 3: Coating Corn Seeds with the Concentrated Algal Extract

[0067] 100 kg of corn seeds are wetted with 100 g of concentrated algal extract prepared in example 1, in a rotary mixer. The seeds are then left to dry at 20-25° C. for 24 hours.

Example 4: Effect of Coating the Seeds on the Emergence of Corn Seedlings

[0068] The coated corn seeds prepared in example 3 are sown on 20 m.sup.2 plots. A control is carried out with untreated corn seeds. A comparative test is carried out with corn seeds coated with a conventional fungicide comprising 25 g/l of fludioxonil and 9.7 g/l of metalaxyl-M.

[0069] 3 weeks after sowing, the number of corn seedlings is counted. The results are presented in FIG. 1. It is observed that emergence of the corn seedlings is favored when the seeds are coated with the concentrated algal extract prepared according to example 1, compared to the uncoated seeds or to the seeds coated with the fungicide.

[0070] Example 4 was reproduced and gave similar results.

Example 5: Bird-Repelling Effect of Coating the Seeds

[0071] During one of the experiments according to example 4, the field was subjected to a particularly aggressive attack by crows. The birds attack the seeds buried in the soil, which leads to a reduction in the number of healthy corn seedlings relative to the number of seeds planted.

[0072] The results are presented in FIG. 2, the values on the y axis being expressed as percentage of healthy corn seedlings relative to the theoretical number of seedlings.

[0073] A significant difference was observed in the degree of attack between the control plots or those treated with the fungicide and the plots in which the seeds were coated with the concentrated algal extract of example 1. Thus, the plots which had been sown with seeds treated with the concentrated algal extract of example 1 were relatively spared by the birds.

[0074] The concentrated algal extract of the present invention therefore has a bird-repelling effect.

[0075] Example 5 was reproduced and gave similar results.