USE OF AN ALUMINOSILICATE GLASS FOR PROVIDING A PLANT WITH SILICON IN AN ASSIMILABLE FORM, METHOD FOR TREATING A PLANT USING THIS GLASS AND NEW POWDER OF THIS GLASS

Abstract

The subject-matter of the present invention is the use of an aluminosilicate glass to provide a plant with silicon in assimilable form, a method for treating a plant using this glass and a new powder of said glass.

According to the invention, this aluminosilicate glass comprises the following constituents in a weight content varying within the limits defined below: SiO.sub.2 30-60% Al.sub.2O.sub.3 10-26% CaO+MgO+Na.sub.2O+K.sub.2O 15-45%.

The invention finds applications in particular in the agricultural field.

Claims

1. A method for providing a plant with silicon in assimilable form which comprises applying to said plant or to a growth medium of said plant an aluminosilicate glass comprising the following constituents in a weight content varying within the limits defined below: SiO.sub.2 30-60% Al.sub.2O.sub.3 10-26% CaO+MgO+Na.sub.2O+K.sub.2O 15-45% as source of silicon.

2. The method of claim 1, wherein, in said aluminosilicate glass, the SiO.sub.2 content by weight is between 35 and 49%.

3. The method of claim 1, wherein, in said aluminosilicate glass, the Al.sub.2O.sub.3 content by weight is between 12 and 25%.

4. The method of claim 1, wherein, in said aluminosilicate glass, the cumulative weight content of CaO, MgO, Na.sub.2O and K.sub.2O is between 20 and 40%.

5. The method of claim 4, wherein, in said aluminosilicate glass: the weight content of CaO is between 8 and 30%; and the weight content of MgO is between 1 and 15%.

6. The method of claim 4, wherein, in said aluminosilicate glass: the weight content of Na.sub.2O is between 1 and 10%; the weight content of K.sub.2O is between 1 and 7%.

7. The method of claim 1, wherein, in said aluminosilicate glass: the sum of the weight contents of CaO and MgO is between 25 and 40%; and the sum of the weight contents of Na.sub.2O and K.sub.2O is between 0 and 6%.

8. The method of claim 1, wherein, in said aluminosilicate glass: the sum of the weight contents of CaO and MgO is between 10 and 25%; and the sum of the weight contents of Na.sub.2O and K.sub.2O is between 8 and 15%.

9. The method of claim 1, wherein said aluminosilicate glass further comprises iron oxide and: the total weight content of iron oxide, expressed in the form Fe.sub.2O.sub.3 is between 0 and 13%.

10. The method of claim 1, wherein, in said aluminosilicate glass, the total weight content of SiO.sub.2, Al.sub.2O.sub.3, CaO, MgO, Na.sub.2O, K.sub.2O and Fe.sub.2O.sub.3 is at least 94%.

11. The method of claim 1, wherein said aluminosilicate glass comprises the following constituents, in a weight content varying within the limits defined below: SiO.sub.2 35-49% Al.sub.2O.sub.3 12-24% CaO+MgO+Na.sub.2O+K.sub.2O 20-40% Fe.sub.2O.sub.3 0-12%.

12. The method of claim 11, wherein said aluminosilicate glass comprises the following constituents in a weight content varying within the limits defined below: SiO.sub.2 36-45% Al.sub.2O.sub.3 14-23% CaO+MgO+Na.sub.2O+K.sub.2O 25-35% Fe.sub.2O.sub.3 0-10%.

13. The method of claim 1, wherein said aluminosilicate glass is in the form of particles having a size distribution such that the volume median diameter of the particles D50 is between 60 and 250 microns.

14. (canceled)

15. The method f of claim 1, wherein the above plant is in a suboptimal nitrogen condition.

16. The method of claim 1, wherein the plant is selected from the group consisting of rice, grassland, rape, sunflower, wheat, oats, sugar cane, barley, soya, and maize.

17. The method of claim 1, wherein the aluminosilicate glass is provided to the plant in an amount between 20 and 500 Kg/T in a form selected from the group consisting of solid form, powder and granules.

18. The method of claim 1, wherein said aluminosilicate glass is supplied to the plant by the roots.

19. An aluminosilicate glass powder comprising: the following constituents in a weight content varying within the limits defined below: SiO.sub.2 30-60% Al.sub.2O.sub.3 10-26% CaO+MgO+Na.sub.2O+K.sub.2O 15-45%; and said glass powder having a particle size distribution such that the volume median diameter of these particles D50 is comprised between 60 and 250 microns.

20. A fertilizer composition comprising at least one nitrogen source in admixture with at least one aluminosilicate glass as defined with comprising the following constituents in a weight content varying within the limits defined below: SiO.sub.2 30-60% Al.sub.2O.sub.3 10-26% CaO+MgO+Na.sub.2O+K.sub.2O 15-45%.

21. The method of claim 1, wherein, in said aluminosilicate glass, the SiO.sub.2 content by weight is between 36 and 45%.

22. The method of claim 1, wherein, in said aluminosilicate glass, the SiO.sub.2 content by weight is between 38 and 44%.

23. The method of claim 1, wherein, in said aluminosilicate glass, the Al.sub.2O.sub.3 content by weight is between 14 and 24%.

24. The method of claim 1, wherein, in said aluminosilicate glass, the cumulative weight content of CaO, MgO, Na.sub.2O and K.sub.2O is between 25 and 35%.

25. The method of claim 4, wherein, in said aluminosilicate glass: the weight content of CaO is between 12 and 28%; and the weight content of MgO is between 1 and 12%.

26. The method of claim 1, wherein, in said aluminosilicate glass: the sum of the weight contents of CaO and MgO is between 27 and 35%; and the sum of the weight contents of Na.sub.2O and K.sub.2O is between 1 and 5%.

27. The method of claim 1, wherein, in said aluminosilicate glass: the sum of the weight contents of CaO and MgO is between 12 and 20%; and the sum of the weight contents of Na.sub.2O and K.sub.2O is between 9 and 13%.

28. The method of claim 1, wherein said aluminosilicate glass further comprises iron oxide and: the total weight content of iron oxide, expressed in the form Fe.sub.2O.sub.3 is between 4 and 12%.

29. The method of claim 1, wherein, in said aluminosilicate glass, the total weight content of SiO.sub.2, Al.sub.2O.sub.3, CaO, MgO, Na.sub.2O, K.sub.2O and Fe.sub.2O.sub.3 is at least 97%

30. The method of claim 1, wherein said aluminosilicate glass is in the form of particles having a size distribution such that the volume median diameter of the particles D50 is between 75 and 180 microns

31. The method of claim 1, wherein the aluminosilicate glass is provided to the plant in an amount between 50 and 300 Kg/T in a form selected from the group consisting of solid form, powder and granules.

32. The aluminosilicate glass powder of claim 19, wherein said glass powder has a particle size distribution such that the volume median diameter of these particles D50 is comprised between 75 and 180 microns.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0116] FIG. 1 is a graph showing the impact of nitrogen fertilizer application on (i) grain yield (solid and diamond lines), (ii) nitrogen leaching losses (bar graph) and (iii) nitrogen efficiency (dashed and square lines).

[0117] FIG. 2 is a graph representing the percentage of silicon (of an aluminosilicate glass according to the invention) dissolved in various acids.

[0118] FIG. 3 is a graph representing the percentage of silicon (from an aluminosilicate glass according to the invention, calcium silicate, diatomaceous earth and soda-lime-silica glass) dissolved in various acids (malic acid A, oxalic acid B, citric acid C and succinic acid D).

[0119] FIG. 4 reproduces the photographs showing the formation of phytoliths in a leaf of rice (Oryza sativa) treated with an aluminosilicate glass according to the invention (V1) and with sodium silicate.

[0120] FIG. 5 is a graph that represents the yield of ryegrass plants, i.e. the dry mass of ryegrass plants, (i) with a nitrogen-free feed, (bar 0); (ii) with a feed containing 60 Kg.Math.ha.sup.1 of nitrogen, (bar 60); (iii) with a feed containing 100 Kg.Math.ha.sup.1 of nitrogen, (bar 100); this dose being considered the suboptimal nitrogen dose that does not achieve optimal yield, (iv) with a feed that includes 140 Kg.Math.ha.sup.1 of nitrogen, (bar 140), this dose being considered as the optimal nitrogen dose which allows the optimal yield to be achieved, and (v) with a feed which comprises 100 Kg.Math.ha.sup.1 of nitrogen and 50 Kg.Math.ha.sup.1 of an aluminosilicate glass according to the invention, (bar 100+aluminosilicate glass).

[0121] FIG. 6 is a graph representing the nitrogen efficiency of ryegrass plants, i.e., the dry mass of ryegrass plants divided by the amount of nitrogen supplied, (i) with a feed which comprises 60 Kg.Math.ha.sup.1 of nitrogen, (bar 60); (ii) with a feed which comprises 100 Kg.Math.ha.sup.1 of nitrogen, (bar 100); (iii) with a feed which comprises 140 Kg.Math.ha.sup.1 of nitrogen, (bar 140); (optimum nitrogen dose which allows optimum yield to be achieved) and (iv) with a feed which comprises 100 Kg.Math.ha.sup.1 of nitrogen and 50 Kg.Math.ha.sup.1 of an aluminosilicate glass according to the invention, (bar 100+aluminosilicate glass).

[0122] FIG. 7 is a histogram showing the particle size distribution of a glass powder used according to the invention.

DESCRIPTION OF THE EMBODIMENTS

Example 1: Preparation of Aluminosilicate Glass Particles According to the Invention

[0123] Two aluminosilicate glass compositions illustrative of the invention were prepared by melting a suitable vitrifiable mixture in accordance with a usual method of obtaining a molten glass mass.

[0124] The compositions of these two aluminosilicate glasses are given in Table 2 below.

TABLE-US-00002 TABLE 2 Glass 1 Glass 2 SiO.sub.2 40.8 43.1 Al.sub.2O.sub.3 16.8 22.8 Na.sub.2O 1.7 6.2 K.sub.2O 1.4 4.0 MgO 6.0 1.8 CaO 25.0 14.6 Fe.sub.2O.sub.3 5.8 5.8 Impurities 2.5 1.7

[0125] After cooling, the mass of glass obtained was crushed by means of a pendulum mill associated with an aerodynamic selector (mill in which the crushing is obtained by crushing the glass between a fixed cylindrical ring with a vertical axis and centrifugal rollers by the rotation of their support).

[0126] The particle size of the glass particles thus obtained was measured by laser diffraction sizing and FIG. 7 shows the particle size distribution of these particles.

[0127] In this example, the following operating conditions were used:

[0128] Device Used: [0129] Mastersizer 2000, Malvern [0130] Accessory Hydro Cell 2000

[0131] Operating Parameters: [0132] Liquid process [0133] Dispersant: alcohol [0134] Refractive index (particle):1.52 [0135] Absorption index (particle):0.01 [0136] Stirring speed: 2000 rpm [0137] Ultrasonic use: no [0138] Measurement time: 6 seconds [0139] Blank measurement time: 6 seconds [0140] Obscuration range: 6.21%.

[0141] The powder obtained had the following characteristic values: [0142] D90: 189 microns [0143] D50: 81 microns [0144] D10: 18.4 microns

Example 2: Demonstration of the Dissolution Properties of an Aluminosilicate Glass According to the Invention in the Presence of Organic Acids

[0145] Plants have the particularity of releasing various organic acids through their roots, such as in particular citric acid, lactic acid, malic acid, oxalic acid, succinic acid, formic acid, acetic acid, pyruvic acid, maleic acid, oxaloacetic acid, ascorbic acid, isocitric acid.

[0146] In order to demonstrate the special dissolution properties of an aluminosilicate glass according to the invention in these organic acids, particles of glass 1 prepared according to example 1 were treated with the following protocol.

[0147] Preparation of Media with Different Organic Acids

[0148] Several media were prepared, and their composition is presented in the following table 3:

TABLE-US-00003 TABLE 3 pH of the Medium Composition of the medium medium Ultrapure water Ultrapure water 7.0 Sulfuric acid Ultrapure water adjusted to pH 2 with concentrated sulfuric acid 2.0 Nitric acid Ultrapure water adjusted to pH 2 with concentrated nitric acid 2.0 Hydrochloric acid Ultrapure water adjusted to pH 2 with concentrated hydrochloric acid 2.0 Phosphate citrate buffer 360 mL 0.5M Na2HPO4 + 220 mL 0.5M citric acid + 1420 mL 4.5 ultrapure water Phosphate oxalate buffer 360 mL 0.5M Na2HPO4 + 220 mL 0.5M oxalic acid + 1420 mL 4.2 ultrapure water Phosphate tartrate 360 mL of 0.5M Na2HPO4 + 220 mL of 0.5M tartaric acid + 1420 mL 4.4 buffer of ultrapure water Citric acid 2%. 40 g citric acid in 2 L ultrapure water 2.0 Succinic acid 2%. 40 g succinic acid in 2 L ultrapure water 2.5 Oxalic acid 2%. 40 g oxalic acid in 2 L ultrapure water 1.2 Tartaric acid 2%. 40 g tartaric acid in 2 L ultrapure water 2.0 Malic acid 2% 40 g malic acid in 2 L ultrapure water 2.1 Glucuronic acid 2% 40 g glucuronic acid in 2 L ultrapure water 2.1 Pyruvic acid 2%. 40 g pyruvic acid in 2 L ultrapure water 1.6 Malonic acid 2% 40 g malonic acid in 2 L ultrapure water 1.8 Gluconic acid 2% 40 g gluconic acid in 2 L ultrapure water 2.3 Phosphate buffer 2.75 g KH2PO4 in 2 L ultrapure water adjusted to pH 8.5 8.5 Phosphate buffer 2.75 g KH2PO4 in 2 L ultrapure water adjusted to pH 11 11

[0149] Dissolution Test

[0150] 100 mg of each product was placed in a 60 ml pill box. 50 ml of each dissolution medium was added and then put under continuous stirring with a rotary shaker (Heidolph reax 2). After 48 h of stirring, the samples were filtered with filter paper with a pore diameter of 15 m. The silicon was measured to determine the percentage of dissolution in each medium.

[0151] Silicon Measurement

[0152] The determination of the silicon (Si) content of the samples was carried out for each sample and for each sampling time by inductively coupled plasma-optical emission spectroscopy using ICP-OES (Inductively Coupled Plasma-Optical Emission Spectroscopy, Thermo Elemental Co. Iris Intrepid II XDL).

[0153] The results are shown in FIG. 2.

[0154] As can be seen, the aluminosilicate glass according to the invention is solubilized in the presence of the organic acids usually released by plants.

[0155] On the other hand, it is noted that no silicon release occurs in aqueous media close to neutral pH.

[0156] This figure also shows that the solubility effect of aluminosilicate glass is not related to pH alone, since the dissolution of silicon is relatively weak in strong acids such as sulfuric, nitric or hydrochloric acid.

[0157] Other tests showed that the release of silicon is congruent with the release of the other constituents of the glass.

Example 3: Demonstration of the Dissolution Properties of an Aluminosilicate Glass According to the Invention in the Presence of Organic Acids in Comparison with Other Forms of Silicon

[0158] In order to demonstrate the particular dissolution properties of an aluminosilicate glass according to the invention in certain organic acids, and to be able to compare this dissolution with that of other forms of silicon, particles of glass 1 prepared according to example 1, calcium silicate, diatomaceous earth and a soda-lime-silica glass illustrating the teaching of document WO 2010/040176 were treated according to the following protocol:

[0159] Preparation of Media with Different Organic Acids

[0160] 4 media each containing a phosphate buffer and an organic acid were prepared: [0161] Medium 1, based on malic acid, is composed of: 360 mL of 0.5M Na.sub.2HPO.sub.4, 220 mL of 0.5M malic acid made up to 2 L with ultrapure water. The measured pH is 4.9 [0162] Medium 2, based on citric acid, is composed of: 360 mL of 0.5M Na.sub.2HPO.sub.4, 220 mL of 0.5M citric acid made up to 2 L with ultrapure water. The measured pH is 4.5 [0163] Medium 3, based on oxalic acid, is composed of: 360 mL of 0.5M Na.sub.2HPO.sub.4, 220 mL of 0.5M oxalic acid made up to 2 L with ultrapure water. The measured pH is 4.2 [0164] Medium 4, based on succinic acid, consists of 2% succinic acid prepared with 40 g of succinic acid supplemented to 2 L with ultrapure water. The measured pH is 2.4

[0165] Dissolution Test

[0166] 100 mg of each product was placed in a 60 ml pill box. 50 ml of dissolution medium was added and then put under continuous stirring with a rotary shaker (Heidolph reax 2). Successive samples of solution are then taken after 1, 2, 5, 8, 24 and 48 h of stirring. The samples taken are filtered with a filter paper with a pore diameter of 15 m. The silicon assay was carried out for each sample to determine its dissolution kinetics in the medium.

[0167] Silicon Measurement

[0168] The determination of the silicon (Si) content of the samples was carried out for each sample and for each sampling time by inductively coupled plasma-optical emission spectroscopy using ICP-OES (Inductively Coupled Plasma-Optical Emission Spectroscopy, Thermo Elemental Co. Iris Intrepid II XDL).

[0169] The results are shown in FIG. 3.

[0170] As can be seen, the aluminosilicate glass according to the invention is gradually solubilized in the presence of the organic acids usually released by plants, such as malic acid A, oxalic acid B, citric acid C or succinic acid D). On the other hand, no release of silicon occurs in these media for diatomaceous earth or soda-lime-silica glass products.

Example 4: Demonstration of the Formation of Phytoliths in a Plant Treated with an Aluminosilicate Glass According to the Invention

[0171] Preparation of Plant Material

[0172] Oryza sativa L. Var ARELATE rice seeds were placed at +4 C. the day before germination to ensure a homogeneous emergence. They were then sown on a perlite layer in tanks containing demineralized water and left in the dark for 10 days before being provided to light. After 7 days, the seedlings were transplanted into 2 L pots containing a mixture of clay beads and vermiculite (50%/50%; V/V) and then received the various treatments at the time of transplanting. The plants were watered three times a week with a Hoagland solution of: KNO.sub.3 (0.2 mM); Ca(NO.sub.3).sub.2, 4H.sub.2O (0.4 mM); KH.sub.2PO.sub.4 (0.2 mM); MgSO.sub.4, 7H.sub.2O (0.6 mM), (NH.sub.4).sub.2SO.sub.4 (0.4 mM); H.sub.3BO.sub.3 (20 M); MnSO.sub.4, H.sub.2O (5 M); ZnSO.sub.4, 7H.sub.2O (3 M); CuSO.sub.4, 5H.sub.2O (0.7 M); (NH.sub.4).sub.6Mo.sub.7O.sub.24, 4H.sub.2O (0.7 M) and Fe-EDTA (200 M). The experiment was conducted in a growing greenhouse at 22 C. with a photoperiod of 12 h day/12 h night. The plants were harvested 48 days after application of the treatment.

[0173] Food that Did not Include Aluminosilicate Glass (Control)

[0174] These plants received only the nutrient solution described above at a frequency of three times a week. The plants were grown in a growing greenhouse at 22 C. with a photoperiod of 12 h day/12 h night.

[0175] Food that Included Aluminosilicate Glass According to Example 1

[0176] These plants received the nutrient solution described above three times a week. The aluminosilicate glass was added during transplanting at a dose of 50 Kg.Math.ha.sup.1 (corresponding to 21 Kg.Math.ha.sup.1 of SiO.sub.2). The plants were grown in a culture greenhouse at 22 C. with a photoperiod of 12 h day/12 h night.

[0177] Food that Included Sodium Silicate

[0178] These plants received the nutrient solution described above three times a week. Sodium silicate was added during transplanting at a dose of 42.6 Kg.Math.ha.sup.1, in order to have the same SiO.sub.2 equivalent (21 Kg.Math.ha.sup.1). The plants were grown in a culture greenhouse at 22 C. with a photoperiod of 12 h day/12 h night.

[0179] Observation and Quantification of Phytoliths in the Plant

[0180] For each of the culture conditions (control, aluminosilicate glass and sodium silicate), four batches of four harvested plants were formed (1 batch=1 biological replicate). The phytolith observation method is based on the autofluorescence of phytoliths developed by Dabney III et al. Plant Methods (2016) 12:3 A novel method to characterize silica bodies in grasses.

[0181] A median section of each leaf blade was cut along the leaf of each plant, placed between two microscope slides, and then placed in a muffle furnace at 500 C. for 3 hours for complete charring of the leaf samples. After a cooling time, the slides were placed under a fluorescence microscope (Zeiss Axio Observer Z1) at 10 magnification. The autofluorescence of the phytoliths was measured using a GFP filter, with excitation between 450-490 nm and emission between 500-550 nm. Quantification of the phytoliths was performed using Zen 2 Pro software. By preselecting an area of the same air on the image and for each modality, the number of phytoliths is calculated using software in number of phytoliths. mm.sup.2.

[0182] The data obtained were presented as photos (for the observation of phytoliths) or means (for the number of phytoliths) and the variability of the results was given as a standard error of the mean for n=4. A statistical analysis of the results was performed using Student's test.

[0183] The accumulation of phytoliths in the plant is shown in FIG. 4.

[0184] Conclusion: plants treated with aluminosilicate glass show a greater accumulation of phytoliths in the leaves. The number of phytoliths in the presence of aluminosilicate glass increases by +86%, compared to the control, and by +93%, compared to sodium silicate. This reflects a better absorption of silicon by the plant in the presence of the aluminosilicate glass according to the invention.

[0185] Additional tests, the results of which are not reported here, have shown that a soda-lime glass illustrating the teaching of WO 2010/040176 also leads to limited phytolith formation.

Example 5: Demonstration of Improved Yield and Nitrogen Efficiency Under Suboptimal Nitrogen Conditions in a Plant Treated with an Aluminosilicate Glass According to the Invention

[0186] Preparation of Plant Material

[0187] Lolium perenne L. Var Abys ryegrass seeds were sown at a density of 240 Kg.Math.ha.sup.1 (corresponding to 2 g of seeds per pot) in 2 L pots containing a mixture of soil and sand (50/50V/V) and then placed in a glasshouse under the following conditions: daytime temperature of 25 C. and a photoperiod of 12 h/nighttime temperature of 20 C. and a photoperiod of 12 h. The soil used had the following characteristics: sandy loamy soil, pH 7.1 and contained 1.6% organic matter. Throughout the trial period, the plants were watered by weight to maintain the soil at 70% of its capacity in the field.

[0188] The term watered by weight, as used in this description, means that the watering is done in an amount to compensate for water losses that may occur through evapotranspiration. In this case, water is added in an amount that will bring the weight of the pot back to its original weight.

[0189] In order to draw residual nitrogen from the soil to obtain a nitrogen response curve, the plants were cultivated for 24 days before making the first cut. This first cut was not analyzed because no treatment was applied at this stage, the objective being to take up the residual nitrogen initially present in the soil. Subsequent treatments were applied 28 days after sowing (4 days after the first cut), varying the amount of nitrogen applied (0, 60, 100, 140 Kg.Math.ha.sup.1): [0190] the first nitrogen fertilization was carried out 28 days after sowing [0191] the second cut/harvest was carried out 68 days after sowing [0192] the second nitrogen fertilization was carried out 69 days after sowing [0193] the third cut/harvest was carried out 103 days after sowing

[0194] The biomass of the plants harvested in the second and third cut were then added together to give the total biomass.

[0195] The following observations were made.

[0196] Food that Did not Include Nitrogen(0 Kg.Math.Ha.sup.1)

[0197] No nitrogen fertilization was applied to the seedlings. This condition is considered a nitrogen deficiency condition as it does not allow optimal yield to be achieved. The plants were watered by weight throughout the trial period to maintain the soil at 70% of its field capacity.

[0198] Food that Included 60 Kg of Nitrogen Per Hectare(60 Kg.Math.Ha.sup.1)

[0199] These plants received 60 Kg of N.Math.ha.sup.1 at the first fertilization in the form of urea, and no nitrogen was applied at the second nitrogen fertilization. This condition is considered as a nitrogen deficiency condition as it does not allow to reach an optimal yield. Plants were watered by weight throughout the trial period in order to maintain the soil at 70% of its field capacity.

[0200] Food that Included 100 Kg of Nitrogen Per Hectare(100 Kg.Math.Ha.sup.1)

[0201] These plants received 60 Kg of N.Math.ha.sup.1 as urea at the first fertilization, and 40 Kg of N.Math.ha.sup.1 as urea at the second nitrogen fertilization. This condition is considered as a suboptimal nitrogen condition as it does not allow to reach an optimal yield. The plants were watered by weight throughout the trial period in order to maintain the soil at 70% of its capacity in the field.

[0202] Food that Included 140 Kg of Nitrogen Per Hectare(140 Kg.Math.Ha.sup.1)

[0203] These plants received 60 Kg of N.Math.ha.sup.1 as urea at the first fertilization, and 80 Kg of N.Math.ha.sup.1 as urea at the second nitrogen fertilization. This condition is considered an optimal nitrogen condition because it allows to reach an optimal yield. The plants were watered by weight throughout the trial period in order to maintain the soil at 70% of its capacity in the field.

[0204] Food that Included 100 Kg of Nitrogen Per Hectare and 50 Kg.Math.Ha.sup.1 of an Aluminosilicate Glass According to Example 1 (Glass 1)

[0205] These plants received 60 Kg of N.Math.ha.sup.1 as urea at the first fertilization, and 40 Kg of N.Math.ha.sup.1 as urea at the second nitrogen fertilization. The aluminosilicate glass was provided during the first fertilization at the dose of 50 Kg.Math.ha.sup.1 and in association with the urea. This condition is considered to be a suboptimal nitrogen condition as it does not allow optimum yield to be achieved. The plants were watered by weight throughout the trial period in order to maintain the soil at 70% of its capacity in the field.

[0206] Measurement of Nitrogen Yield and Efficiency

[0207] Yield was determined by evaluating leaf biomass according to the following protocol. For each of the growing conditions (0, 60, 100, 140 and 100+100 aluminosilicate glass), and for each cut/harvest (second and third cut/harvest), six batches of harvested plants were formed (1 batch=1 biological replicate). The aerial parts (leaves and stems) of the plants were weighed (fresh biomass) then dried in an oven (at 70 C. for 2 days) to obtain the total dry biomass. Biomasses from the second and third harvest were added to obtain total biomass. Measurements of the dry biomass of the plants that represents the yield are shown in FIG. 5. The data obtained were presented as a mean and the variability of the results was given as the standard error of the mean for n=6. A statistical analysis of the results was performed using Student's test.

[0208] Conclusion: Under suboptimal nitrogen conditions (i.e. 100 Kg.Math.ha.sup.1), plants treated with the aluminosilicate glass according to the invention show a significant 12% increase in yield, which translates into better ryegrass growth under this low nitrogen condition. FIG. 5 also shows that the plants having received the suboptimal dose of nitrogen and the aluminosilicate glass have the same yield as the plants having received the optimal dose of nitrogen (140 Kg.Math.ha.sup.2). This result shows that the aluminosilicate glass according to the invention stimulates the yield under suboptimal nitrogen conditions, and makes it possible to achieve the same yield as that obtained with the plants having received the optimal dose of nitrogen.

[0209] Nitrogen efficiency was subsequently calculated using the following formula, presented by Good et al. 2004; Dawson et al. 2008:

[00001]$\mathrm{Nitrogen}\mathrm{efficiency}=\frac{\mathrm{Total}\mathrm{biomass}\mathrm{produced}\left(\mathrm{cut}1+\mathrm{cut}2\right)}{\mathrm{Total}\mathrm{amount}\mathrm{of}\mathrm{nitrogen}\mathrm{provided}}$

[0210] The resulting measures of nitrogen efficiency are shown in FIG. 6. The data obtained were presented as a mean and the variability of the results was given as the standard error of the mean for n=6. A statistical analysis of the results was performed using Student's test.

[0211] Conclusion: Under suboptimal nitrogen conditions (i.e. 100 Kg.Math.ha.sup.1), plants treated with the aluminosilicate glass according to the invention show a significant 11% increase in nitrogen efficiency, which translates into a better increase in yield per unit of nitrogen supplied under this low nitrogen supply condition. This result also shows that plants having received the suboptimal dose of nitrogen and the aluminosilicate glass have a nitrogen efficiency +42% higher than that obtained with plants having received the optimal dose of nitrogen (140 Kg.Math.ha.sup.2). The aluminosilicate glass according to the invention therefore improves the nitrogen efficiency in suboptimal nitrogen conditions.