Agricultural product, and preparation method

Abstract

An agricultural product as well as its manufacturing method, the product being solid, disintegrable and including at least one agricultural active ingredient and one matrix based on a plant-origin material, the matrix having a plant protein content of at least 30% by weight relative to the dry weight of the plant-origin material and a lipid content of at most 10% by weight relative to the dry weight of the plant-origin material, and being present in the product in a proportion of at least 75% by weight relative to the weight of the product, and the agricultural active ingredient being dispersed, in a homogeneous way, in the matrix, the product having a density from 1300 to 1500 kg/m.sup.3.

Claims

1. A solid, disintegrable agricultural product comprising at least one agricultural active ingredient and a matrix based on a plant-origin material, said matrix having a plant protein content of at least 30% by weight relative to the dry weight of said plant-origin material and a lipid content of at most 10% by weight relative to the dry weight of said plant-origin material, and being present in said product in a proportion of at least 75% by weight relative to the weight of the product, and said agricultural active ingredient being dispersed, in a homogeneous way, in said matrix, wherein said product has a density of 1300 to 1500 kg/m.sup.3.

2. The agricultural product according to claim 1, wherein the matrix has a plant protein content of at least 35% in weight relative to the dry weight of said plant-origin material.

3. The agricultural product according to claim 1, wherein the matrix is obtained from cake(s) chosen from among sunflower cakes, legume cakes, soybean, flax cakes, crucifer cakes, rapeseed and any mixture of these cakes, the cake(s) having been optionally enriched with protein.

4. The agricultural product according to claim 1, wherein all or part of the plant-origin material is in a form resulting from a transition into the molten state.

5. The agricultural product according to claim 1, wherein the proportion of the matrix is at least 80% by weight relative to the weight of the product.

6. The agricultural product according to claim 1, wherein the proportion of the agricultural active ingredient(s) ranges from 5% to 25% by weight relative to the weight of the product.

7. The agricultural product according to claim 1, wherein it comprises at least one additive, said additive being able to be chosen from lubricating agents, matrix plasticizing agents and cohesive agents.

8. The agricultural product according to claim 1, wherein the agricultural active ingredient(s) are chosen from fertilizers, natural defense stimulators, herbicides, fungicides, insecticides, parasiticides, repellents, and are chosen from or resulting from natural substances of plant, animal, microbial or mineral origin.

9. The agricultural product according to claim 1, wherein it comprises urea, in a proportion of 5% to 25% by weight relative to the weight of the product.

10. The agricultural product according to claim 1, wherein it is in the form of granules, tablets or pellets.

11. The agricultural product according to claim 1, wherein it meets at least one of the following properties: abrasion resistance at least equal to 98%, tensile elastic modulus at least equal to 200 MPa and less than 1850 MPa, bending elastic modulus at least equal to 85 MPa and less than 1500 MPa, Shore D surface hardness of between 37.5° and 70°, weight gain from 35% to 60% after 1 h of immersion in water, from 60% to 100% after 3 h, and from 100% to 160% after 6 h.

12. A method of manufacturing an agricultural product according to claim 1, wherein it is implemented in a twin-screw extruder comprising a barrel inside which are disposed two co-rotating and co-penetrating (or interpenetrated) parallel screws, and equipped with at least two inlets for feeding, an outlet for the extruded product and heating elements, said extruder being optionally associated with a die of the extruded product, and it comprises the following steps: introduction of at least one plant-origin material and one agricultural active ingredient, and optionally one or more additives, in a first feed inlet of said extruder and premix of them by action of interpenetrating conveyor screws; addition of water, and optionally of one or more additives, to the premix through a second feed inlet; heating to a temperature of at least 80° C. to obtain a homogeneous mixture; application of compressive, kneading and shearing stresses to said mixture by action of the screws; and densification of the extruded product, recovered at the outlet of the extruder or die, to obtain said agricultural product.

13. The method according to claim 12, wherein the proportion of the plant-origin material and optionally of the additives, in the premix is at least 75% by weight relative to the weight of the premix and the proportion of the agricultural active ingredients in the premix is at most 25% by weight relative to the weight of the premix.

14. The method according to claim 12, wherein the water is added to the premix in a proportion of 20% to 50% by weight relative to the weight of the premix.

15. The method according claim 12, wherein the extruder is equipped with several series of decrease pitch conveyor screws, making it possible to apply the compressive stresses to said mixture.

16. The method according to claim 15, wherein the extruder is equipped with two successive pairs of bilobed kneading discs, mounted in a staggered fashion, making it possible to apply the kneading stresses to said mixture, said discs being disposed following, directly or indirectly, pitch decrease conveyor screws.

17. The method according to claim 16, wherein the extruder is equipped with several successive pairs of reverse pitch elements (or counter-threads), making it possible to apply the shearing stresses to said mixture, said elements being disposed following, directly or indirectly, said discs.

18. The method according to claim 12, wherein the agricultural active ingredient contains or consists of urea.

19. The method according to claim 12, wherein it comprises a step of adding urea, in a proportion of 5% to 20% by weight relative to the weight of the premix.

20. The method according to claim 12, wherein, after recovery of the product at the outlet of the extruder, it comprises a step of drying the agricultural product to reach a moisture level of between 15% and 20% by weight relative to the weight of the product.

21. The method according to claim 12, wherein the densification of the extruded product is carried out by thermoplastic injection or hot compression.

22. The method according to claim 21, wherein it comprises a step of plastic injection of the product, and the product is gradually heated, to a temperature of between 110° C. and 140° C., before injection molding.

23. A plant-origin material which has a plant protein content of at least 30% relative to the dry weight of said material and a lipid content of at most 10% relative to the dry weight of said material, configured as a disintegrable matrix to support an agricultural active ingredient.

24. A plasticizing agent comprising urea for the manufacture in a twin-screw extruder of an agricultural product as defined in claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0074] The disclosure is illustrated with the following examples from which its advantages will emerge and in support of the following FIGS. 1 to 8:

[0075] FIG. 1 represents the nitrogen salting out rate from urea by different products.

[0076] FIG. 2 represents the fresh weight of spinach leaves from cultures treated with different products.

[0077] FIG. 3 represents the dry weight of spinach leaves from cultures treated with different products.

[0078] FIG. 4 represents the fresh weight of spinach roots from cultures treated with different products.

[0079] FIG. 5 represents the dry weight of spinach roots from cultures treated with different products.

[0080] FIG. 6 represents the amount of chlorophylls (chlorophyll a (Ca) and chlorophyll b (Cb)) and carotenoids accumulated in the spinach leaves from cultures treated with different products.

[0081] FIG. 7 represents the amount of nitrogen accumulated in the spinach leaves and roots from cultures treated with different products.

[0082] FIG. 8 represents the amount of nitrates accumulated in the fresh spinach leaves from cultures treated with different products.

DETAILED DESCRIPTION AND EXAMPLES

Example 1: Properties of Products of the Disclosure

[0083] Products of the disclosure, PTUd, PSUd and PLUd, comprising a matrix consisting of, respectively, sunflower (T), soybean (S) and flax (L) cake (91% w/w) and urea (U) (9% w/w) as active ingredient are manufactured and their properties are compared with those of three reference products PT, PS and PL (outside the disclosure) composed of a matrix consisting of cakes, not containing active ingredient and not being densified, as well as these three densified products PTd, PSd and PLd.

[0084] Matrices are prepared from the following cakes respectively: [0085] sunflower cake enriched with protein by simple sieving of a sunflower industrial cake [0086] soybean cake obtained by solvent oil extraction, and [0087] flax cake obtained by first cold pressing of flax seeds.

[0088] Their protein and lipid contents are given in table 1 below: they are expressed in % by weight relative to the weight of the dry matter.

TABLE-US-00001 TABLE 1 Cake Fraction Enriched sunflower (T) Soybean (S) Flax (L) Proteins 50.7 46.0 37.0-42.0 Lipids 1.4 2.2 7.7

[0089] The products PTU, PSU and PLU, respectively, are manufactured by extrusion according to the technology involved and described previously.

[0090] The products PTUd, PSUd and PLUd of the disclosure are obtained by densification of the PTU, PSU and PLU products, respectively, by plastic injection, according to a variant of the method of the disclosure described above.

[0091] The reference products PT, PS, PL, PTd, PSd and PLd, not containing active ingredient, are manufactured using the same methods.

[0092] 1.1 Characterization of the Products of the Disclosure by their Physico-Chemical and Mechanical Properties

[0093] The values of the non-densified products and of the densified products according to the disclosure are grouped in table 2 below.

TABLE-US-00002 TABLE 2 Product PTU PTUd PSU PSUd PLU PLUd Density (kg/m.sup.3) 1122.5 1398.2 702.5 1406.9 881.9 1361.1 Abrasion 88.5 99.6 82.5 99.3 92 98.7 resistance (%) Tensile elastic nd 476 nd 224 nd 216 modulus Ey (MPa) Bending elastic nd 295 nd 133 nd 91 modulus Ef (MPa) Shore D hardness nd 46.9 nd 48.9 nd 37.7 (°) nd: not determined

[0094] 1.2. Test of Salting Out Nitrogen from the Active Ingredient by Products of the Disclosure

[0095] The salting out of nitrogen by the products PTUd, PSUd and PLUd is measured after immersion of the products in water contained in a tray, for 1 hour and for 3 hours, respectively. At the end of immersion, the products are removed from the tray and are then left to drain completely on a metal grid. The liquid resulting from this draining is recovered, filtered in order to eliminate any solid particles in suspension and weighed. Finally, the part of nitrogen present in this liquid is metered using the Kjeldahl method according to the ISO standard 5983-1:2005.

[0096] The reference products PTd, PSd and PLd were subjected to the same treatment. The part of nitrogen which could be measured in the liquid resulting from the draining necessarily comes from the proteins present in the plant-origin material.

[0097] The quantity of nitrogen salted out respectively by the products of the disclosure PTUd, PSUd and PLUd coming specifically from urea is calculated by subtracting the quantity of nitrogen metered in the draining liquid of the reference products PTd, PSd and PLd to that metered in the draining liquid of the products of the disclosure PTUd, PSUd and PLUd.

[0098] The results of the metering of the nitrogen in the products of the disclosure are presented in FIG. 1.

[0099] These results demonstrate, on the one hand, the effectiveness of the “encapsulation” of urea in a matrix based on plant matter according to the method of the disclosure with respect to the salting out of nitrogen and, on the other hand, the control of the diffusion of urea, the latter not being accelerated over time and remaining progressive.

[0100] 1.3. Test of Immersion in Water of Products of the Disclosure

[0101] The tests were conducted on the products PTUd, PSUd and PLUd of the disclosure, as well as on the products PT, PS and PL, the products PTd, PSd and PLd and the products PTU, PSU and PLU, all defined at the beginning of example 1, and the compared results. They are reported in Table 3 below.

TABLE-US-00003 TABLE 3 Caking after immersion in water (%) Formulation — 1 h 3 h 6 h 24 h PT Average 79.5 85.8 Disintegrated Disintegrated ± 0.4 4.2 PTd Average 40.4 61.1 98.3 119.3 ± 1.6 1.1 4.5 3.0 PTU Average 142.9 151.9 Disintegrated Disintegrated ± 1.6 2.7 PTUd Average 37.0 78.4 111.4 157.0 ± 1.0 10.0 23.4 25.8 PS Average 204.3 207.6 Disintegrated Disintegrated ± 0.4 1.6 PSd Average 45.2 75.9 120.2 162.3 ± 1.2 1.0 4.1 16.5 PSU Average 142.1 152.3 Disintegrated Disintegrated ± 3.3 0.1 PSUd Average 57.1 95.5 156.0 212.7 ± 0.5 1.5 21.0 26.0 PL Average 170.0 233.5 Disintegrated Disintegrated ± 2.9 2.8 PLd Average 54.2 60.4 126.1 Partially ± 1.2 1.1 20.0 disintegrated PLU Average 196.1 247.8 Disintegrated Disintegrated ± 2.6 4.7 PLUd Average 49.0 78.1 159.0 Partially ± 3.3 7.2 16.3 disintegrated

[0102] The following observations emerge from these results: [0103] when it can be measured, that is to say when the product is not yet disintegrated, the caking in water is always lower for the products of the disclosure compared to the non-densified products outside the disclosure, for the same formulation, right from the start; [0104] after 6 hours of immersion, only the products of the disclosure have not yet disintegrated.

Example 2: Efficacy Test in the Salting Out of an Active Ingredient of Manure Type from a Product of the Disclosure on a Spinach Cultivation

[0105] It is known that the cultivation of spinach requires a sufficient supply of nitrogen manure to ensure optimal growth of the leaves which are intended for human consumption.

[0106] 2.1 Equipment and Methods of Agronomic Tests

[0107] Spinach (Spinacia oleracea L.) was sown on a commercial substrate of Evergreen TS (Turco, Italy) type cultivation. The plants were cultivated in a greenhouse under natural light conditions. When the first two leaves appeared, the plants were transplanted to the substrate in 2 L (13 cm×13 cm×13 cm) pots (5 plants per pot and 5 pots per essay).

[0108] After one week, the manures were added according to the scheme described below: [0109] Essay No. 0: control (culture substrate alone); it is a control essay without fertilization; [0110] Essay No. 1: culture substrate+PTd (4 g per pot, 277 mg N); [0111] Essay No. 2: culture substrate+PTUd (2.5 g per pot, 285 mg N), this is a fertilization essay with a product according to the disclosure; [0112] Essay No. 3: culture substrate+urea (0.25 g per pot, 50 mg N); [0113] Essay No. 4: Osmocote® (1.5 g per pot, 285 mg N); this is a control essay with the addition of an Osmocote® PRO 3-4 slow-release commercial manure (NPK) (ICL Italia Treviso, Italy), implemented at the dose recommended by the manufacturer.

[0114] The amount of manures PTd and PTUd added to each pot, for essays No. 1 and No. 2 respectively, was calculated in order to introduce the same amount of nitrogen as in the control essay No. 4. The essay No. 3 contained the same amount of urea as the essay No. 2.

[0115] At the end of the experiment, the plants were all healthy and had reached a satisfactory size with no apparent difference between the essays.

[0116] After 55 days, the leaves and roots were collected, and their respective fresh weights were measured. Two plants per pot were dried at 60° C. until reaching a constant weight for the determination of the dry weight of the leaves and roots.

[0117] The chlorophyll content was determined on the fresh leaves from two plants per pot. The N content of dry leaves and roots was measured after crushing by elemental analysis.

[0118] The performance indicators of the tested products were (i) the production of biomass (leaves and roots), (ii) the content of chlorophyll and carotenoids, (iii) the total concentration of nitrogen and (iv) that of nitrates.

[0119] 2.2 Results obtained

[0120] 2.2.1 Effects on the Fresh Weights and the Dry Weights of the Leaves

[0121] The results are reported in FIG. 2 (fresh weight) and FIG. 3 (dry weight).

[0122] With nitrogen fertilization (essays No. 1 to No. 4), the average dry weight of the leaves is 2.2 g/plant against only 1.6 g/plant for the control carried out without fertilization (essay No. 0).

[0123] It is observed that the essay No. 2 (product according to the disclosure) leads to the highest fresh weights and dry weights of leaves. This result demonstrates a proven (and cumulative) fertilizing effect of the product PTUd resulting from the nitrogen supply by (i) urea salted-out but also (ii) its proteins, present at 51% of its dry mass.

[0124] 2.2.2 Effects on the Fresh Weights and the Dry Weights of the Roots

[0125] The results are reported in FIG. 4 (fresh weight) and FIG. 5 (dry weight).

[0126] With nitrogen fertilization (essays No. 1 to No. 4), the recorded average values are slightly higher than with the non-fertilized essay (essay No. 0). Nevertheless, the differences observed are not significantly different and no relationship between the root/leaf ratio (with an average value of 0.06) and nitrogen fertilization has been demonstrated.

[0127] 2.2.3 Effects on the Chlorophyll Content

[0128] The contents of chlorophyll a (first bar of each essay in the histogram), chlorophyll b (second bar of each essay in the histogram) and carotenoids (third bar of each essay in the histogram) in the leaves are reported in FIG. 6. Despite high standard deviations, these contents remain higher in the case of nitrogen fertilization (essays No. 1 to No. 4) than for the control essay (essay No. 0). The use of PT, without or with urea (essays No. 1 and No. 2, respectively), comparable to that of urea alone (essay No. 3), is even beneficial in comparison with the tested commercial manure (essay No. 4).

[0129] 2.2.4 Effects on the Nitrogen Content of the Leaves and Roots

[0130] FIG. 7 shows that the nitrogen uptake by the leaves (first bar of each essay in the histogram) of the plants fertilized with TP-based samples (essay No. 1 and No. 2) or with pure urea (essay No. 3) is higher than in the cases of the control essay (essay No. 0) and even of the plants fertilized with the Osmocote® commercial manure (essay No. 4). The uptake of N by the roots (second bar of each essay in the histogram) is on average lower than that of the leaves.

[0131] The high N content of the leaves implies a high protein concentration and therefore a cultivation with better nutritional value.

[0132] 2.2.5 Effects on the Nitrate Content of the Fresh Leaves

[0133] FIG. 8 shows that the fresh leaves of the control plants (essay No. 0) have the lowest nitrate content, followed by the fresh leaves of the plants fertilized with Osmocote® (essay No. 4). Conversely, the fresh leaves of the plants fertilized with PTd (essay No. 1), PTUd (essay No. 2) and pure urea (essay No. 3) have much higher nitrate contents.

[0134] It should be remembered that the accumulation of nitrates in spinach leaves may be critical. The European Commission has indeed published a regulation (No. 1258/2011, Eur-lex, 2011) fixing the maximum acceptable concentration of nitrates in spinach at 3500 mg NO.sub.3.sup.−/kg in fresh spinach, 2000 mg NO.sub.3.sup.−/kg in canned or frozen spinach, and 200 mg NO.sub.3.sup.−/kg in baby food.

[0135] The urea added at a dose of 0.25 g (essay No. 3) therefore has a negative impact due to the higher nitrate content in the fresh leaves of the plants. This content is reduced by replacing the urea with PTUd (essay No. 2) or with PTd (essay No. 1).

[0136] It is therefore observed that the nitrate content in the fresh leaves of plants treated with a product of the disclosure (PTUd) is always well below the maximum value of 3500 mg NO.sub.3.sup.−/kg of fresh leaves tolerated by European regulations.

[0137] These examples demonstrate that a product of the disclosure, despite a low disintegration speed, brings a gain to the treated plants greater than that of products outside the disclosure and in particular than that of non-densified products. This effect is surprising. It has thus been demonstrated the benefit conferred by products of the disclosure in the field of agriculture, compared to the products of the prior art.

[0138] In conclusion, an agricultural product according to the disclosure makes it possible to reduce the amount of active ingredient without compromising plant growth. In addition, it allows to reduce the negative impact on the environment and on human health, caused by a high applied dose of active ingredient.