The present invention refers in general to products that can be used in agriculture to promote or enhance growth of cultivated plants, and therefore their production yield.

Growth of cultivated plants, for example ornamental plants, is affected by several factors such as availability of light, carbon dioxide, oxygen, heat, water, nutrients, etc., which form as a whole the so-called pedoclimatic complex, the action of which can be improved by agronomic interventions such as irrigation, fertilization and tillage.

In particular, fertilization plays a fundamental role since it allows the nutrients necessary for improving the growth of the plants to be brought. It is therefore known that an excessive and indiscriminate use of nutrients can cause environmental damages, such as eutrophication of the surface water and groundwater pollution.

Currently, the need of agricultural techniques is increasingly felt which allows, on the one hand, high production levels and, on the other hand, a sustainable growing of the plant from an environmental point of view, with a low impact on the agro- ecosystem.

In particular, attention of the most advanced research is paid, in addition to mineral compounds and fertilizers used to improve the physical characteristics of the soil, known as a soil improver and commonly used for the nutrition of the plants, also to organic molecules with complex structures such as for example algae, free amino acids, proteins, plant extracts of various origin, humic and fulvic acids, which actively act on plant metabolism and absorption of mineral nutrients, to increase productivity and decrease the demand for fertilizers .

Use of these substances allows the yield of the crops to be optimized and the contribution of fertilizers to be increased, and also helps the plants to overcome environmental stress conditions of various kinds.

In particular, the invention relates to a biostimulating composition based on tannins and/or their derivatives, for the treatment of cultivated plants and/or parts thereof, that can be used to promote or enhance the production yield and the growth of cultivated plants.

The use of tannins in agriculture is known, although somewhat controversial, since its role and effectiveness have not been fully clarified. It is in fact generally known that tannins, when administered in high amounts, especially on the ground, involve inhibitory effects on the plant growth. In this regard, the publication entitled "Effects on tannins on plants and Their productivity" by G. Muthukmumar, Sivaramarkishnan R. and A. Mahadevan, reports that administration of tannins to certain varieties of plants, even in relatively low percentages, plays the role of inhibitor of the seed germination, of the elongation of roots and of the plant growth.

Nevertheless, studies and experiments carried out by the Applicant shown that tannins and their derivatives, used according to generally reduced amounts, are instead useful to promote plant growth, in particular of various cultivated or ornamental plants.

In fact, the results achieved from use of the compositions according to the invention confirm that the tannins act as biostimulating elements for the plants, as they contain substances which, when applied to the plants or the rhizosphere, stimulate the natural processes, improve the absorption of nutrients, increase the tolerance of plants against biotic and abiotic stresses, and improve the quality of the crop, regardless of the amount of other nutrients used.

More particularly, the invention relates to a composition of the type defined above, comprising:

- a first component including tannins, the amount of which is between 0.1 and 40% by weight of the composition, and

- a second component substantially consisting of a solvent, said first and second components being mixed to form a solution or a dispersion of said tannins and/or their derivatives, which is adapted to be applied on the plants through dispensing by perfusion.

According to a preferred feature of the invention, the amount of tannins used in the above composition is comprised between 0.1 and 15% by weight of the composition, preferably between 0.5 and 2% by weight of the composition.

The tannins used in the composition of the present invention include various types of tannins, such as condensed and/or hydrolyzable tannins, and/or phlorotannins . In particular:

condensed tannins of the procyanidin and/or prodelfinidin type, such as of maritime pine (Pinus pinaster), of Chilean pine (Araucaria Araucana) , of Pecan nuts (pecan) , of Spruce (Picea abies) , of Douglas, of fir etc.,

and/or

condensed tannins of the prorobinetinidin and/or profisetinidin type, such as of Mimosa (Acacia mearnsii, Acacia mollissima, Acacia mangium, Acacia catechu) , of Quebracho

(Schinopsis lorentzii, Schinopsis balansae) , of Gambier

(Uncaria gambir) , etc.,

and/or

- hydrolysable tannins, such as of chestnut (Castanea sativa, Castanea vesca) , of Tara (Caesalpinia spinosa) , etc.,

and/or

- phlorotannins extracted from algae,

can be used.

These tannins can be possibly employed also in their form purified by extraction with organic solvents, through processes such as acylation, methylation, ethoxylation, propoxylation, etc., and/or in their form modified or transformed by means of various chemical and physical reactions, such as polymerization, oxidation or enzymatic or chemical hydrolysis, and/or with the introduction of amino groups, so that the tannins can also be in the form of sulphited, sulphonated, oxidized, acetylated, esterified, ethoxylated or propoxylated substances, or possible mixtures thereof.

The solvent of the second component of the composition consists preferably of water, and/or glycols, and/or polyalcohols, and/or polar or ionic solvents.

Tests and trials performed by the Applicant shown that ability of tannins and/or their derivatives to promote the growth of the plants, can be increased if they are used in association or in mixture with organic salts and/or minerals of various elements or substances such as ammonium (NH ₄ ) , potassium (K) , phosphorus (P) , calcium (Ca) , molybdenum (Mo) , iron (Fe) , zinc (Zn) , magnesium (Mg) , manganese (Mn) , copper (Cu) , cobalt (Co) , boron (B) , for example in the form of sulfates, chlorides, nitrates and carbonates of these elements or substances. In particular, salts of only one of these elements or substances can be used, or combinations of salts of the various elements and substances mentioned above.

Association of tannins and/or derivatives thereof with these salts, revealed that they play a bio-stimulating effect for the action of the salts, so that their effectiveness can be improved and the growth properties of the plants can be enhanced.

In particular, the compositions containing tannins and/or their derivatives according to the invention shown that their use in combination with salts based on the elements and substances mentioned above, for example potassium chloride (KC1) or zinc sulphate (ZnS0 ₄ ) , allows an efficacy significantly greater than that obtainable by the use of the individual constituents to be obtained, particularly in the case of the application of the product on the leaves of the plants (foliar application) .

With specific reference to KC1, its use in agriculture is known per se. In fact, KC1 is used as a fertilizer for several kinds of crops, alone or in a mixture with other fertilizers. It can be used, if necessary, by foliar distribution to make its effect quicker.

Among KC1 components, potassium (K) , which is present in the form of a cation, is a macro-element since it is assimilated in high quantities by the plants, and it constitutes the main element of the favorable role of KC1 in the plant metabolism. In particular, potassium affects the osmotic potential of the cells and improves ability to absorb water from the soil, it takes part in the metabolism processes of carbohydrates in the photosynthesis, it presides over the functions of synthesis of amino acids and proteins, it acts on cellular division and, at any rate, it seems to be able to positively affect the entire photosynthetic activity. Potassium, by virtue of these features, can help to improve quantitatively and qualitatively the growth of the plants and their fruits.

The other component of KC1, chlorine (CI) , in the form of chloride ion, performs an important function for the plant metabolism. It stimulates photosynthesis, being necessary in the photosynthetic water splitting reaction during which oxygen is generated, it plays an indispensable role in cell division of leaves and roots and in gas exchange, in concentrations lower than those of potassium. However, the chloride ion may be toxic to plants in high concentrations.

It has however been found that use of a composition containing tannins and/or their derivatives together with KC1 involves a synergistic effect which considerably improves the effects on productivity, compared to those obtained from application of the individual products, although it is not completely clear if this synergistic effect arises owing to association of the tannin with potassium alone, or with chloride alone, or to association of tannins with both potassium and chloride.

Similar results were obtained for compositions based on tannin and/or their derivatives in combination with salts of other elements, for example as a result of the use of zinc sulphate.

In particular, it was found that the compositions according to the invention, in which tannins are associated with potassium chloride and/or zinc sulfate, according to the proportions defined in the following, also increase the stimulating effect of tannins, especially in the case of tannins separated from substances that may cause possible sedimentation in successive aqueous solutions.

As an alternative or in combination with potassium chloride and/or zinc sulphate, salts of other elements or substances can also be used in order to obtain a beneficial effects on the regulation of plant metabolism. For example, the copper (Cu) is a micro-element useful to the plants, that is commonly used as a control agent of some important fungal diseases of the plants.

However, copper based treatments may also develop adverse effects, depending on the plant species. In fact, copper is considered to be potentially phytotoxic since it reduces efficiency of the photosynthesis and development of the plant, particularly in foliar treatment, and it may therefore have an adverse impact on plant growth. For this reason, copper is not used, except for in very small amounts, on stone fruits in the period in which the plants develop their leaves, because it involves phytotoxic effects in the early vegetative stages of the plants. For the vine, where it is used to oppose the downy mildew, and for the apple tree, where it is used to oppose the scab, it performs a growth retardant effect which decreases efficiency of the plants.

Moreover, an excessive presence of copper in the ground, deriving from phytosanitary treatments of the leaves, must however be avoided because it tends to gather, causing damaging effects on the ecosystem.

As a result of tests and trials performed by the Applicant, it was however found that use of tannins reduces phytotoxicity of copper, as well as of other elements administered to the plants and absorbed through the leaves or through the soil.

The administration of the composition according to the invention may take place by several techniques of application by perfusion on the ground, in the substrates used for cultivation (hydroponics, vessels, etc.), through irrigation, on the seeds before sowing, in which case it may also form a coating layer of the seeds, or on the aerial parts of the plants .

The effectiveness of using compositions based on tannins and/or their derivatives in the treatment of cultivated plants, revealed to be more evident in the case in which their application takes place on the aerial parts of the plants.

This fact was observed in the cultivation of plants in normal or ideal climatic conditions and soil composition, but it is very evident in the case of cultivation of the plants in abiotic stress conditions, and even under biotic stress conditions. In fact, just in the most difficult growing conditions, caused by adverse climatic conditions or compositions of the soil unfavorable for cultivation, or by the presence of parasites such as nematodes, the use of tannins and/or their derivatives has proved to be very useful to adjust and improve the physiological processes of the plants, and to increase strength of the crops, as well as productivity, quality and conservation of the plants after harvesting.

The compositions of the invention are preferably applied by direct perfusion on the leaves, on the green parts, on the neck, on the reproductive system, on the seeds, on the roots, on the bulbs, on the tubers, or on the cuttings of cultivated plants. This allows a considerable bio-stimulating and invigorating effect to be attained, which causes a considerable increase in production and an increased efficiency of fertilizers and/or crop protection products administered to plants, such as to allow the required amount of fertilizers and/or crop protection products to be reduced, and therefore to reduce the potential phytotoxicity of these products. In this manner, a more harmonious and balanced development of the plants can be obtained, which allows a higher yield in the growth of fruits, berries, seeds, roots, tubers, flowers and green parts to be achieved.

The positive effects of the compositions of the present invention are promoted by application by means of localized perfusion, such as spraying or atomization or other known distribution systems, which consist therefore in a preferred form of application.

In particular, application of the compositions of the invention by foliar perfusion allows remarkable results to be achieved, compared with other modes of application, such as that on the ground, with particularly low amounts of product.

The compositions according to the invention containing tannins and/or their derivatives, together with possible organic and/or minerals salts, such as KC1 and/or ZnS0 ₄ and/or copper salts, are preferably prepared from a basic dilutable preparation in the form of a solute liquid or of a powder, having a relatively high concentration and intended to be diluted in water or in other solvents, such as water and/or glycols and/or polyalcohols and/or other polar or _. ionic solvents, to make easier their application by using dispensing devices, typically spraying devices, known per se.

The dilutable base preparation comprises a first component that includes tannins and any salts, the amount of which is generally between 40 and 60% by weight of the base preparation, so that, as a result of its dilution, the composition of the invention can be obtained so as to include the indicated amounts of tannins and of any salts.

Moreover, the compositions of the invention may contain dispersant additives in order to improve stability in time, as well as their adhesion on the leaves or the ability to retain moisture. These additives consist, for example, of lignosulphonates, stillage derived from sugar cane and/or beet, humic and fulvic acids, and/or polysaccharides such as vegetable gums, particularly guar gum, xanthan gum and tara gum, or polyethylene glycol and/or glycerin, or combinations thereof.

The compositions according to the invention may also contain extracts of algae, of amino acids, of saponins, and/or of microorganisms, for example of the genus Trichoderma, to promote their use in organic farming.

Application of the compositions of the present invention comprising tannins and/or their derivatives and possible salts, involves at any rate the use of amounts of the compositions of few kilograms per hectare of cultivation, and thus relatively reduced doses on large surfaces. Preferably, the total amount of the first component of the composition, that is of the component including tannins and/or their derivatives and/or at least one organic and/or mineral salt, to be used in the treatment steps during the entire life cycle of the plants, generally varies between about 1 and 80 kg per hectare of cultivation.

At any rate, the compositions of the present invention, in view of the use of relatively low amounts of tannins and/or their derivatives, allow a high productivity to be obtained with a reduced impact on the ecosystem of the soil, in particular on soil microflora, and on the environment, in addition to a greater economic sustainability.

In the experimental tests carried out by the Applicant, substantial positive effects on crops have been observed, such as a stimulation of the growth of the plants, a greater root development, an increase in the size and number of fruits, of the seeds and tubers, an increase in the content of chlorophyll, a greater consistency and shelf life of the agricultural products.

Furthermore, the compositions based on tannins and/or their derivatives according to the invention have proven to be able to confer to the plants an increased resistance to abiotic stress due to environmental factors that inhibit the growth of the plants, such as the high temperature, the drought, the salinity of the soil, the presence of phytotoxic salts, · the excess of water in the soil, the ultraviolet rays, the strong wind which cause the transpiration of the plants to be increased, as well as a greater resistance to biotic stress due to presence of parasites, in particular nematodes.

With reference to the latter, they consist of small worm-like invertebrates that are often present in very sandy and/or humid soils, which are able of infesting a large variety of plants, particularly at root level. The presence of nematodes makes the soil inhospitable for agronomic crops, since they cause problems to the lymphatic circulation and problems to the growth of the plants up to involve their death. In the past, nematode infestations were usually opposed by the use of chemical nematicides such as soil fumigants, which have recently been the subject of considerable restrictions, being considered to be very toxic to human beings and the environment. This made it harder to oppose nematode infestations in the agricultural grounds. The present invention has also revealed an unexpected effectiveness in opposing nematode infestations in agronomic crops.

The compositions of the invention also promote the secondary plant metabolism resulting in an increased productivity of molecules (phytoalexins , phenols and polyphenols, terpenes, suberins, etc.) which are able to repel attacks by plant pathogens, and thus enhance the natural resistance of plants against harmful organisms, resulting in an invigorating effect.

The positive effects described above on the phenotype of the plants can be attributed to a balanced development, which is made evident by the fact that the trunks have a diameter greater than that of the untreated plants, the leaves have a larger size and are greener by virtue of the fact that production of chlorophyll is promoted, and also the strength and uniformity of the crops is improved. This allows plants and fruits to be obtained of a greater caliber and in a greater number and/or weight per unit of cultivated area, and therefore a better yield. Furthermore, compactness and shelf life of the produced agricultural products are improved.

Therefore, use of the compositions of the invention, in addition to increasing productivity of the treated plants, has the benefit of a reduced need for use of potentially polluting and/or expensive substances as fertilizers, crop protection products, and crop conditioning agents, also owing to the fact that the compositions at issue have a direct effect on physiology of the plant also through the improvement of the soil characteristics and/or availability and stability of the fertilizer used.

In addition, the compositions of the invention, dispensed directly on crops, do not involve toxic effects on plants or human beings or the environment, and it can be therefore used in organic farming.

The cost of the treatments carried out by using the compositions of the invention are at any rate largely compensated for the benefits of increase in production that can be obtained for a wide range of crops, such, for example, soy, corn, tomatoes, lettuce, potatoes, and other agronomic crops. Merely by way of example, the highest yield obtainable in vegetable intensive crops usually varies between 10 and 15%, but can reach 18-20% in leaf crops such as lettuce. In the case of extensive crops of herbaceous crops, average increments of 8-10% can be reached, up to 20% in optimal conditions.

Another advantage of the compositions of the present invention is to allow their use together with the common fertilization and agronomic protection treatments deriving from the application of protocols defined as a result of multi-year researches carried out on different crops, and selected among the many tested in years of experimental assays, which are deemed to be able to provide optimum results. In particular, the methods of perfusion, dosage and timing of application of the composition of the present invention were found to be optimal under the conditions reported in the following examples.

Furthermore, use of compositions based on tannins and/or their derivatives according to the invention has shown the characteristic of preventing that phytotoxic effects may occur in the presence of high or excessive concentrations of salts in the soil, for example caused by agronomic treatments of the soil or by irrigation water, or by the composition itself of the soil.

The present invention thus involves the use of relatively low amounts of tannins, in particular with reference to the treated surface of the soil and/or to the number of plants present in it, which are further reduced in the case of the combination of tannins and/or their derivatives with KC1 and/or other salts, so as to allow any possible inhibitory effect by tannins on growth of the treated plants to be avoided. By virtue of the fact that combined use of tannins and/or their derivatives together with KC1 involves a significantly greater effect than that obtainable from the use of the individual components, it is possible to use a reduced amount of the various components on plants, in order to achieve the same beneficial effects. In particular, this allows to improve environmental sustainability of the use of the compositions of the invention with respect to the use of tannins alone, and to improve also the economic impact of the treatments, by decreasing the amount of substances used, and therefore their cost .

As mentioned above, the beneficial effects of the compositions of the invention on plants are increased when salts and/or other micro-elements are present in them.

In spite of the fact that positive effects of the combined use of tannin and/or its derivatives together with KC1 emerged for all methods of application on crops, for example as a result of their application on the ground or around the seeds or on the fruits, a process of application of the composition by localized distribution on the leaves of the plant provided very positive results.

Moreover, the relatively low amount of tannins and/or their components used, in the case of their combination with the salts mentioned above, significantly improves the positive effects that can be obtained with respect to use of the tannins alone distributed on the ground, because the plants, as a result of distribution of the composition on the leaves, are subjected to a greater stimulation despite the use of smaller amounts of tannins per unit area (hectare = ha) of the treated soil .

The compositions of the invention comprising tannins and/or their derivatives in combination with the mentioned salts, compared with the best fertilizers and foliar biostimulants currently on the market, have shown a better activity on agricultural productivity with respect to known products, in different tests and with the same dosage.

In particular, by treating the plants with the compositions according to the invention containing tannins together with KC1 and/or ZnS0 ₄ , an increase in the intensity of the green coloring of the leaves has been ascertained, which is directly correlated with a greater photosynthetic activity.

It can therefore be concluded that use of the compositions according to the invention promotes a rise in the photosynthetic index, also as a result of the decrease of the toxic effect (inhibitory, phytotoxic) of the copper, of the chlorine and of other chemical compounds, when they are present over a threshold normally acceptable by plants.

- EXAMPLES

In the following examples the main results obtained experimentally by the Applicant as a result of the use of compositions according to ^' the invention are provided, which were applied to various crops, and in different weather conditions and soil. The compositions according to the invention used in the tests described below were obtained by dilution in a solvent, usually water, that may also consist of water and/or glycols and/or polyhydric alcohols and/or other polar or ionic solvents, of a basic preparation comprising a first component including tannins, possibly associated with the mentioned salts, the amount of which can vary generally between 40 and 60% by weight of the base preparation to be diluted.

In particular, to assess the effectiveness of the used treatments, reference has been made also to the health and wellbeing level of the plants, which can be measured by using various measurement techniques as the strength of the plants, the productivity in fruit, or by using the so-called "photosynthetic index" to quantify the plant photosynthesis activity. When this index is less than 0.8 the plant has a weakened photosynthetic activity, while when it is greater than or equal to 0.8 the metabolism of the plant takes place in an optimal manner.

In the evaluation of the effectiveness of the compositions according to the. present invention on the plants, the photosynthetic index was measured by using the SPAD (spectrophotometric measurement of the intensity of the green color of the leaves) technique.

- Example 1: Tests on lettuce

- Example 1.1

In the present ^' example, the effect of foliar treatment with tannins was assessed on the development and productivity of plants of lettuce (Lactuca sativa L.) subjected to abiotic stress conditions caused by a high temperature (2 days every 10, with temperatures > 35 °C) and by soil with high average salinity (conductivity values of 3.5-4 dS/m at 25°C, and high pH of the water used for irrigation) , and strong light intensity. These abiotic stress conditions are usually able to decrease the lettuce productivity by 25% compared to the ideal climatic and ground conditions.

The test was repeated in three different sites, with four repetitions for each composition. Each plot of land included 120 plants arranged on six rows spaced of 0.30 m to each other and having a length of 6 m, the plants of each row being spaced of about 0.30 m. The measurements were carried out at a portion of one of the central rows of the plot of a length of 5 m, that is on 15 plants.

In order to prepare the composition, tannins of quebracho, mimosa, chestnut, tare, 50/50 chestnut/quebracho and phlorotannins were separately dissolved in water. For the different kinds of tannins, solution dosages variable between 0.1 and 40 kg per hectolitre (hi) of solution of the composition were used, and the best results were obtained for dosages ranging between 0.1 and 15 kg per hi. The optimum dosage was found to be 0.1 to 1 kg per hectolitre of solution.

The application of the composition on the plants was carried out by perfusion by atomization or nebulization on the leaves in three subsequent applications, by using amounts of solution comprised between 150 and 300 1/ha, depending on the state of the crop growth. In particular, a first treatment was performed 5-7 days after transplantation of the lettuce seedlings with 150 1/ha of solution, a second treatment after other 7-10 days with 200 1/ha, and a last treatment after other 7-10 days with 300 1/ha.

The test results were evaluated as a function of the strength of the plants, expressed on the basis of the surface covered by each plant, and of the average weight of the plants, for each dosage and type of tannins compared to an untreated sample. The following Table 1 shows the data obtained for the treatment doses of 1 kg/hi of aqueous solution of quebracho tannin, for the overall application of 6.5 kg/ha of tannins. Treatment with other types of tannins provided similar results.

Table 1: Tests on lettuce treated with tannins only

in abiotic stress conditions

- Example 1.2

The test of example 1.1 was repeated in similar conditions, but using only tannins with a different concentration, KCl alone, or KCl in combination with tannins, respectively.

In the case of the composition containing both tannins and KCl, the latter was added to the tannin solution by using the tannin/KCl weight ratio of 5:1. Also in this case the results were evaluated as a function of the strength expressed on the basis of the surface covered by the plants and of the average weight of the plants for each dosage and type of composition used, with respect to an untreated sample. The following Table 2 shows the data obtained as a result of a treatment performed with an aqueous solution of quebracho tannin of 0.5 kg of solution per hi. Therefore, a total of 3.25 kg/ha of tannin were used. Treatment with other types of tannins provided similar results.

Table 2: Tests on lettuce treated with tannins and/or KC1, in abiotic stress conditions

Plant weight +7% +15% +44%

- Example 1.3

The test of example 1.1 was repeated in ideal agro-climatic conditions, by using, in addition to the tannin solution alone, KC1 and ZnS0 ₄ alone or together with tannin.

In the case of the compositions containing tannins together with KC1 or ZnS0 ₄ , these latter were added to the tannin solution by using tannins/KCl or tannins/ZnS0 ₄ weight ratio of 5:1, respectively. Moreover, the same compositions were prepared by adding also saponins, trichoderma and protein hydrolysates obtained from algae.

As in the previous examples, the results were evaluated function of the strength of the plants expressed on the basis of the area covered by them, as well as of their average weight for each dosage and type of tannins used, with respect to an untreated sample. The following Table 3 shows the data obtained for a treatment performed with an amount of 0.5 kg of quebracho tannin per hi of aqueous solution, for a total application of 3.25 kg/ha of tannin. Similar results were obtained for treatments carried out with other types of tannins.

Table 3: Tests on lettuce treated with tannins and/or KC1, ZnS0 ₄ under ideal conditions

Compared with the previous example 1.2, the measured increases in weight and strength were in each case much lower, probably owing to lack of abiotic stress conditions for the plants, which were in ideal agro-climatic conditions. The results obtained by applying the same compositions with the addition also of saponins, trichoderma and protein hydrolysates obtained from algae, proved to be better just for a few percentage points compared to the data shown in Table 3, which does not involve changes in the conclusions summarized below.

In conclusion, as it ensues from the experimental results of the tests reported in the examples 1.1 to 1.3, it can be said that the more the abiotic stress to which a plant is subjected is high, the more the beneficial effect obtained from use of the compositions of the invention is evident. The best performances were obtained in the tests carried out on plants subjected to strong abiotic stress and with high growth rates.

- Example 2: Test on tomatoes

- Example 2.1

In the present example, the effect of foliar treatment with tannins on development and productivity of tomato plants (Lycopersicon esculentum) was assessed in abiotic stress conditions caused by high temperatures (maximum temperatures higher than 30-35°C, in the period between the last decade of January and the second decade of February, the tests having been carried out in Argentina) and high incidence of fungal diseases, resulting in the need of use of agricultural chemicals, for example based on copper. Therefore, the tomato plants were subject to thermal stress and oxidative stress.

The test was repeated in three different sites, each with four repetitions for each product tested. Each plot of land included two rows of plants having a length of 7 m, spaced 0.4 m to each other, with a density of 20,500 plants per hectare (ha). The measurements were carried out on all plants of the plot of land.

Quebracho, mimosa, chestnut, tare, sulphited quebracho, or oxidized quebracho tannins dissolved separately in water were employed to prepare the compositions used in the various tests, and the application by perfusion of the compositions took place by foliar atomization or nebulization, according to amount of solution comprised between 250 and 700 1/ha, depending on the state of development of the crop.

Variables dosages of the composition containing tannins, varying between 0.25 and 40 kg per hectolitre of solution, were applied, with the addition of 5 g/1 of tara gum in order to increase adhesion and permanence of the solution on the fruits and leaves of tomato. The best results were achieved with dosages ranging between 0.5 and 15 kg/hi, and the optimal dosage was found to be 1 kg per hectolitre of solution.

In the present test, a first application was performed 21 days after transplantation of the tomato seedlings, and the following tests were carried out every 10 days, for a total of 7 applications with dosages of 415, 485, 623, 675, 725, 700, 753 1/ha, respectively. A total of 43.76 kg/ha of each type of tannin were applied.

The results were evaluated as a function of the strength of the plants, of the changes in vegetative habit (habitus) and productivity (increase in yield and fruit quality) , compared to untreated samples. Strong increases in the average weight of the fruits and their calibre, increases in height and number of stands, larger size of the leaves, trunks with a larger diameter, and a greater number of fruit per stand were observed, especially for some dosages and types of tested compositions .

In order to make the sample homogeneous, 10 tomatoes were collected for each plot of land, by collecting the 3 ^rd or 4 ^th tomato from the insertion of the raceme. The following Table 4 shows the values of increase in the yield of the plants, in terms of diameter, number and weight of fruits, obtained following to the application of the composition containing tannin of sulphited quebracho. Also in this case, tests performed with other types of tannins have provided similar results .

Table 4: Tests of tomato treated with tannins only

in abiotic stress conditions

- Example 2.2

The test of the example 2.1 was repeated by using chestnut tannin only, KC1 only, or KC1 in combination with tannin, respectively .

For the composition containing tannin together with KC1, the latter was added to the solution according to the tannin/KCl weight ratio of 5:1.

The tomato plants were cultivated under environmental or abiotic stress conditions, caused by high temperatures (compared to the optimal temperature trend) , and in asphyxiated grounds owing to compactness of the soil. this example, the tests were carried out on plots of land treated with half doses compared to those of Example 2.1. The data obtained turn out to be of particular interest in that the mixture of tannins and KC1 promoted increases in the weight of the fruit up to 9%, equivalent to that obtained with a double dose of tannin only, according to the previous example.

In conclusion, it can be noted that in the latter test a result equivalent to that of the Example 2.1 was obtained, but using only half dose of tannin in combination with KC1. The following Table 5 shows the results obtained for the treatments carried out with 0.5 kg of composition per hectolitre of solution. Therefore, a total of 21.88 kg/ha of tannins, 4.376 kg/ha of KC1, or the sum of the amounts set out above of tannins in combination with KC1, were applied, respectively. Use of other types of tannins provided similar results.

Table 5: Tests of tomato treated with tannins and/or

KC1 in abiotic stress conditions

Weight of fruits +5% +4% +9%

Example 2.3: Tests on tomato plants in biotic stress conditions .

In the present example, the effect of the treatment of the roots of tomato plants with industrial use destination (Solanum lycopersicum L. ) was assessed, by means of drip irrigation with a composition based on tannins or tannins and ZnS0 , or on tannins and chemical standards, to evaluate growth and productivity in biotic stress conditions caused by a nematode (Meloidogyne incognita L.) infestation, and to compare it with productivity obtained in the absence of treatments or with standard treatments based on chemical pesticides (Fenamiphos in pretransplant followed by Oxamyl in post transplant, or with Abamectin and Iprodione) .

Crops of tomato plants were prepared in a soil infested by nematodes, with plots of land with experimental pattern the size of which was 1.80 x 3.60 m, covered by two tunnel shaped greenhouses in the size of 4 x 60 m. The tests were performed according to four repetitions, therefore by carrying out four tests in each greenhouse, each on a respective plot.

In particular, tomato plants were planted in each plot with a density of approximately 22,000 plants per hectare, with rows spaced of 1.8 m, the plants of each row being separated by 0.25 m. Drip irrigation was performed with water, to flush for 3.5 mm/ha per day, corresponding to 35 m ³ /day.

Four aqueous solutions were prepared for the treatment tests with tannin based compositions, the first with quebracho tannin (extract purified by solvents) , the second with chestnut tannin (extract purified by solvents) , the third with fir tannin (extract purified by solvents) , and the fourth with tara tannin (extract purified by solvents), each containing 40% of tannins. Each solution so prepared, prior to its use, was dispersed in water to obtain respective compositions with a tannin concentration of 0.2%. In the treatment tests with tannins together with MnS0 ₄ and ZnS0 ₄ , for each kilogram of 40% solution of tannin in water as described above, 80 g of ZnS0 ₄ , 27 g of MnS0 ₄ and 50 g of a 2% tara gum suspension in a water/propylene glycol mixture according to a proportion of 80:20 by weight, were added.

Each composition was used in five ferti-irrigation applications, with an amount of tannins equivalent to 15 kg/ha. The first application of the compositions was performed 7 days after the transplantation of the plants in the ground, and the subsequent 4 applications at intervals of 21 days, for a total administration of 75 kg of tannin per hectare.

The results of the tests performed were evaluated depending on the total tomato production in kilograms per plot, considering the gall index.

The gall index is defined as:

∑ (number of roots x infestation class) /total number of roots where the infestation class, in accordance with the Lamberti scale of 1971, can assume the following values:

0: No gall on the roots (healthy plant)

1: 1-5 galls on the roots (light infestation)

2: 6-20 galls on the roots (moderate infestation)

3: more than 20 galls (severe infestation)

4: root system reduced and deformed by some large galls 5: root system completely compromised.

The data obtained from the tests carried out on tomato plants subjected to biotic stress owing to an infestation of nematodes, are shown in Table 6 for the situations of the absence of treatment, standard chemical treatment, or treatment with a composition according to the invention based on tannins only, or based on tannins together with MnS0 ₄ and ZnS0 ₄ , respectively. The tests of Table 6 are specifically referred to the data recorded in the tests carried out with quebracho tannins, but tests performed with other types of tannins have provided similar results.

Table 6: Test on tomato plants treated with tannins or with tannins and ZnS0 ₄ , in biotic stress conditions caused by the presence of nematodes

In conclusion, although the gall index of the roots of the plants was not subjected to any appreciable change as a result of the treatments carried out with the compositions of the invention, at any rate a significant increase in the productivity of the plants was observed with the use of tannin, compared to untreated plants. As can be noted, this increase was about 40% in the case of the use of tannin alone, about 49% for the use of tannin together with the standard chemical treatment, and about 47% for the use of tannin together with ZnS0 ₄ and MnS0 . Therefore, it has to be concluded that, with particular reference to this last treatment, that productivity of the plants treated with the compositions of the invention is greater than that obtainable from the same plants subjected to standard chemical treatments, which, as mentioned above, are considered toxic.

- Example 3: Tests on vine

In the present example, the effect of treatments carried out on the leaves of vine plants (Vitis vinifera L. ) by a tannin based composition (consisting of 47.5% of chestnut tannin, 47.5% of quebracho tannin, and 5% of phlorotannins extracted from algae) together with an inorganic copper based salt, was evaluated.

The treatment effect was evaluated in water scarcity conditions, taking into account the photosynthesis index, and therefore efficiency of photosynthesis in the plants. In particular, the results obtained for:

- No treatment: untreated plant sample;

- Treatment with tannins only (1.25 kg/hi solution);

- Treatment with copper salt only (0.5 kg/hi of tribasic copper sulfate solution, Cuproxat) ;

- Treatment with tannins together with copper salt (1.25 kg/hi + 0.5 kg/hi solutions),

were compared.

In total, five applications were made on a weekly basis, as of July 21 and until August 20, and each application involved distribution of 7-10 hi of composition solution per ha.

A statistical evaluation of the data collected allowed the photosynthetic rate of the plants to be quantified, the average values of which are provided below. For the untreated sample containing neither tannin nor copper, an average photosynthetic index of 0.788 was detected, which corresponds to a value lower than normal, owing to the scarcity of water to which the plants were subjected.

For the plants treated with a composition based on copper salts only, the photosynthetic index has provided an average value of 0.775, which means that the plants were in conditions of further stress, in addition to that already caused by the slight water scarcity.

For the plants treated with a tannin based composition only, the average value of the photosynthetic index was found to be 0.799.

The treatment carried out with a tannin based composition together with copper salts, provided an average value of the photosynthetic index of 0.794.

These data support the conclusion that use of tannins, applied on the green parts of the vine, allows a surely positive effect to be obtained, which can be measured as an improvement in the photosynthetic index. This result is valid for compositions either based on tannins only, or on tannins combined with copper salts.

In particular, it was shown that use of tannins implies a beneficial effect on plants, which protects them against the stress action caused by toxicity of copper applied to the leaves .

- EXAMPLE 4 : Tests on Soy

In this example the effect on the development and productivity of soy plants (Glycine max L.) was evaluated, which was achieved by the use of a tannin based composition applied by aspersion by foliar treatment in abiotic stress conditions, particularly water stress (shortage of water) and heat stress.

Tannins of quebracho, of mimosa, of chestnut, of tara were used, dissolved separately in water and applied on the plants by a single foliar atomization or nebulization treatment, in an amount of 100 1 of aqueous solution per hectare, with a 1% concentration of tannins. 5 g/1 of pectin were added to the tannin solution in order to increase its adhesion on the leaves. Application of the composition was carried out during the R2 reproductive phase of the plants. The test was repeated in three cultivation sites with different climate and ground characteristics: in a first site water and heat stress conditions, in the second site only water stress conditions, and in the third site ideal or optimal agro-climatic conditions were present.

The results obtained were evaluated as a result of the comparison of the yield in weight obtained for the soy seeds of the treated plants, with respect to an untreated sample. Average increases of 9-10% compared to the untreated sample were observed for the test performed on the ground subjected to water and heat stress, regardless of the type of tannins used. For the ground subjected to water stress only, the measured average increases were of 10-11%, while in conditions lacking in any abiotic stress (both thermal and water) an average yield increase of 6% was achieved compared to not treated plants.

These data allow to conclude that treatments involving the use of tannin on soy cause a positive effect, especially when the plants are subjected to stress conditions, particularly water stress .

- Example 5: Tests on alfalfa seeds

In this test, a composition containing quebracho sulphited tannin together with KC1 was used, dissolved in a solvent consisting of water and 1 , 2-propanediol (propylene glycol) with the addition of a catalyst agent of polymerization of tannins in an alkaline environment. The latter may consists of zeolite or, as an alternative, of precipitated silica, colloidal silica or crystalline silica.

In particular, 250g of alfalfa seeds were used in the test with 70g of composition in aqueous solution, and 125g of calcium carbonate (CaC0 ₃ ) .

The composition used comprised a part of solvent consisting of 35g of water, in which 35g of a compound prepared by mixing tannins, KC1, zeolite, propylene glycol and water were dissolved.

Calcium carbonate was added to the composition so prepared to give it alkalinity, so as to allow polymerization of the tannin . The composition so obtained was used for coating alfalfa seeds by pelleting, using a rotary drum machine.

After loading the seeds into the rotary drum, dosed perfusion of the dosed aqueous solution of the composition was started, followed by dosed adding of calcium carbonate. At the end of the treatment performed in the rotary drum, the seeds were coated by a layer of a uniform composition. They were then transferred to a fluid bed oven maintained at 40 °C, where they remained for about one hour, to allow complete polymerization of the tannin. The polymerization phase of the tannin, as an alternative, may be carried out within the rotating drum, by blowing a hot air stream.

The coated seeds thus obtained were sown in pots to perform a comparison with the yield obtainable from untreated seeds, and grown under abiotic stress conditions caused by water scarcity, using an amount of water lower than 25% with respect to the optimal one.

Sowing took place at the beginning of March. The biomass was harvested to simulate mowing the field, performing a first cut after two months from sowing, and other two mowings every six weeks, for a total of three mowings. The results were evaluated according to the total biomass produced, either as a fresh substance, or as a dry substance.

The total fresh biomass obtained from the treated seeds was on average 15% higher than that obtained from the untreated seeds. For the total dry biomass an increase of 12% was observed. The same test was carried out with KC1 alone (added with vinyl glue in place of the compound containing tannin of the example referred to above) , or with KC1 together with tannin (in place of the vinyl glue) .

The total fresh biomass of the treated seed was on average 5% higher than that obtained from untreated seeds. An increase of 3% was observed for this total dry biomass.

By using chestnut tannin instead of sulphited quebracho tannin, in the same manner and under the same conditions, a seed coating of very similar looking was obtained. The final results, in terms of increase in the produced biomass, were comparable .