FERTILISING COMPOSITION WHICH INCLUDES A PLANT-ASSIMILABLE PHOSPHORUS AND CALCIUM POTENTIATOR AND USE THEREOF

Abstract

The invention provides a fertilising composition which includes a plant-assimilable phosphorus and calcium potentiator, said assimilable phosphorus potentiator being glyceric acid, a combination of said fertilising composition together with other fertilisers and/or biostimulants, as well as its use in the form of a hydrosoluble powder, granulate or liquid prior dissolution in water for direct application by fertigation or foliar application.

Claims

1. A fertilising composition comprising a plant-assimilable phosphorus and calcium potentiator, wherein the plant-assimilable phosphorus and calcium potentiator is glyceric acid.

2. The fertilising composition according to claim 1, comprising 100% by weight of the glyceric acid in the form of a hydrosoluble powder or in a water-dissolved form.

3. The fertilising composition according to claim 1, comprising 30 to 80% by weight of the glyceric acid and 5 to 30% by weight of other components selected from the group consisting of sugars, amino acids, organic acids other than glyceric acid, polyamines, glycerol, myoinositol, adenine, uracil, cytosine, guanine and combinations thereof, the fertilising composition being in the form of a hydrosoluble powder.

4. The fertilising composition according to claim 3, wherein the sugars are selected from sucrose, fructose, trehalose, glucose, arabinose, maltose, as well as mixtures thereof.

5. The fertilising composition according to claim 3, wherein the amino acids are selected from threonine, lysine, phenylalanine, glutamic acid, methionine, GABA, ornithine, glycine, glutamine, aspartic acid, serine, asparagine, tyrosine, tryptophan, valine, leucine, isoleucine, proline, 4-hydroxyproline, arginine, histidine, alanine, cysteine, and mixtures thereof.

6. The fertilising composition according to claim 3, wherein the organic acids other than glyceric acid are selected from lactic acid, succinic acid, oxalic acid, gluconic acid, threonic acid, fumaric acid and mixtures thereof.

7. The fertilising composition according to claim 3, wherein the polyamines are selected from putrescine, spermidine, spermine and mixtures thereof.

8. A combination of the fertilising composition according to claim 3 with another additional fertiliser selected from nitrogen fertilisers, phosphate fertilisers, potassium fertilisers, calcium fertilisers and amendments, micronutrients, boric acid and leonardite, as well as combinations thereof.

9. The combination according to claim 8, wherein the fertilising composition is present in the combination in a proportion of 0.5 to 10% by weight.

10. The combination according to claim 8, wherein the additional nitrogen fertiliser is present in the combination in a proportion of 5 to 90% by weight and is selected from urea, ammonium nitrosulphate, potassium nitrate, ammonium sulphate, ammonium nitrate, calcium nitrate.

11. The combination according to claim 8, wherein the additional phosphate fertiliser is present in the combination in a proportion of 5 to 90% by weight and is selected from phosphate rock, triple superphosphate, single superphosphate, concentrated superphosphate, and phosphoric acid.

12. The combination according to claim 8, wherein the additional potassium fertiliser is present in the combination in a proportion of 5 to 90% by weight and is selected from potassium chloride, potassium sulphate, potassium and magnesium double sulphate, and potassium hydroxide.

13. The combination according to claim 8, wherein the additional calcium fertiliser is present in the combination in a proportion of 5 to 90% by weight and is selected from calcium chloride, calcium cyanamide, calcium sulphate, dolomite, limestone, calcium oxide, and calcium hydroxide.

14. The combination according to claim 8, wherein the additional micronutrient fertiliser is present in the combination in a proportion of 1 to 30% by weight and is selected from iron sulphate, magnesium sulphate, zinc sulphate, manganese sulphate, copper sulphate, ammonium molybdate, and cobalt chloride.

15. The combination according to claim 8, wherein boric acid as an additional fertiliser is present in the combination in a proportion of 1 to 30% by weight.

16. The combination according to claim 8, wherein leonardite as an additional fertiliser is present in the combination in a proportion of 5 to 90% by weight.

17. The combination of the fertilising composition according to claim 3 with one or more biostimulants selected from the group consisting of amino acid hydrolysates, humic extracts, algae extracts, live micro-organisms or extracts of micro-organisms and combinations thereof.

18. The combination according to claim 17, wherein the biostimulants are present in the combination in a proportion of 5 to 90% by weight.

19. A use of the fertilising composition according to claim 1 in the form of a hydrosoluble powder, granulate or liquid form prior dissolution in water for application by fertigation or foliar application.

20. The use according to claim 19, wherein the composition is applied in a quantity of 0.5 to 20 kg/ha and 0.06 to 1 kg/ha as a hydrosoluble powder by fertigation or foliar application prior dissolution in water, respectively.

21. The use of the combination according to claim 8, in the form of a hydrosoluble powder, granulate or liquid form prior dissolution in water for application by fertigation or foliar application.

22. The use according to claim 21, wherein it is applied directly in an amount of 75 to 1,500 kg/ha in granulate form.

23. The use according to claim 21, wherein it is applied by fertigation or foliar application in an amount of 0.5 to 20 kg/ha and 0.06 to 1 kg/ha respectively.

Description

DETAILED DESCRIPTION

[0015] As mentioned above, in a first aspect, the present invention provides a fertilising composition which includes glyceric acid as a plant-assimilable phosphorus and calcium potentiator.

[0016] In one embodiment, the fertilising composition of the invention consists of 100% by weight of glyceric acid in the form of a hydrosoluble powder.

[0017] In another embodiment, the fertilising composition of the invention comprises between 30 and 80% by weight of glyceric acid and between 5 and 30% by weight of other components selected from the group consisting of sugars, amino acids, organic acids other than glyceric acid, polyamines, glycerol, myoinositol, adenine, uracil, cytosine, guanine and combinations thereof, the fertilising composition being in the form of a hydrosoluble powder.

[0018] When present in the present fertilising composition, sugars are preferably selected from mono- and di-saccharides such as sucrose, fructose, trehalose, glucose, arabinose, maltose, as well as mixtures thereof.

[0019] When present in the present fertilising composition, amino acids are preferably selected from threonine, lysine, phenylalanine, glutamic acid, methionine, GABA, omithine, glycine, glutamine, aspartic acid, serine, asparagine, tyrosine, tryptophan, valine, leucine, isoleucine, proline, 4-hydroxyproline, arginine, histidine, alanine, cysteine, and mixtures thereof.

[0020] When present in the present fertilising composition, the organic acids other than glyceric acid are preferably selected from lactic acid, succinic acid, oxalic acid, gluconic acid, threonic acid, fumaric acid and mixtures thereof.

[0021] Polyamines, if present in the present composition, are preferably selected from putrescine, spermidine, spermine and mixtures thereof.

[0022] The presence of these components other than glyceric acid in the composition of the invention is based on the fact that such components form part of the root exudates in the crops tested in the absence of phosphorus described below or are described in the literature as components of said exudates under normal conditions for plant development (Zhalnina et al, “Dynamic root exudate chemistry and microbial substrate preferences drive patterns in rhizosphere microbial community assembly”, Nat Microbiol, 3(4):470-480, 2018), which are therefore desirable for the aforementioned purpose of having a fertilising composition that mimics root exudates with a similar effect that can make it possible to dispense with or reduce the application of mineral fertilisers.

[0023] The fertilising composition of the invention is formulated as a hydrosoluble powder, as indicated above, but can also be formulated as a liquid composition by dissolving it in water or in the form of granulates by adding granulating agents known to the person skilled in the art.

[0024] According to the second aspect, the invention relates to a fertilising composition as described above in combination with another additional fertiliser selected from nitrogen fertilisers, phosphate fertilisers, potassium fertilisers, calcium fertilisers and amendments, micronutrients, boric acid and leonardite and combinations thereof, and/or in combination with one or more biostimulants selected from the group consisting of amino acid hydrolysates, humic extracts, algae extracts, live micro-organisms, extracts of micro-organisms and combinations thereof. The live micro-organisms or extracts of micro-organisms shall preferably be of the species Pichia guilliermondii, Azotobacter, chroococcum, Bacillus megaterium, Bacillus aryabhattai, Oceanobacillus picturae, or bacteria belonging to genera recognised for their phosphorus solubilising capacity: Pseudomonas, Bacillus, Rhizobium, Burkholderia, Achromobacter, Agrobacterium, Micrococcus, Aerobacter, Flavobacterium, Mesorhizobium, Azotobacter, Azospirillum, Erwinia, Paenibacillus and Oceanobacillus (Rodriguez and Fraga, “Phosphate solubilizing bacteria and their role in plant growth promotion”, Biotechnology Advances 17 (1999) 319-339, 1999; El-Tarabily and Youssef, “Enhancement of morphological, anatomical and physiological characteristics of seedlings of the mangrove Avicennia marina inoculated with a native phosphate-solubilizing isolate of Oceanobacillus picturae under greenhouse conditions”, Plant Soil (2010) 332:147-162, 2010; Zhu et al., 2018, supra).

[0025] In this case, the composition of the invention is present in the combination in a proportion of 0.5 to 10% by weight.

[0026] In one embodiment, the additional nitrogen fertiliser is present in the combination in a proportion of 5 to 90% by weight and is selected from urea, ammonium nitrosulphate, potassium nitrate, ammonium sulphate, ammonium nitrate, calcium nitrate.

[0027] In another embodiment, the additional phosphate fertiliser is present in the combination in a proportion of 5 to 90% by weight and is selected from phosphate rock, triple superphosphate, single superphosphate, concentrated superphosphate, phosphoric acid.

[0028] In yet another embodiment, the additional potassium fertiliser is present in the combination in a proportion of 5 to 90% by weight and is selected from potassium chloride, potassium sulphate, potassium and magnesium double sulphate, potassium hydroxide.

[0029] In another embodiment, the additional calcium fertiliser is present in the combination in a proportion of 5 to 90% by weight and is selected from calcium chloride, calcium cyanamide, calcium sulphate, dolomite, limestone, calcium oxide, calcium hydroxide.

[0030] In yet another embodiment, the additional micronutrient fertiliser is present in the combination in a proportion of 1 to 30% by weight and is selected from iron sulphate, magnesium sulphate, zinc sulphate, manganese sulphate, copper sulphate, ammonium molybdate, cobalt chloride.

[0031] In a further embodiment, boric acid as an additional fertiliser is present in the combination in a proportion of 1 to 30% by weight.

[0032] In another embodiment, leonardite as an additional fertiliser is present in the combination in a proportion of 5 to 90% by weight.

[0033] In the case of the combination of the fertilising composition of the invention with biostimulants as described above, preferably the biostimulants are present in the combination in a proportion of 5 to 90% by weight.

[0034] It is also the object of the invention to use the fertilising compositions described here in the form of a hydrosoluble powder, in the form of a granulate or in the form of a liquid prior dissolution in water for the application thereof by fertigation or foliar application.

[0035] If the composition of the invention is used in the form of a hydrosoluble powder by fertigation or by foliar application prior dissolution in water, it is preferably applied in an amount of 0.5 to 20 kg/ha and 0.06 to 1 kg/ha respectively.

[0036] If the composition of the invention is used in combination with another additional fertiliser in the form of a granulate, preferably said combination is applied directly in an amount of 75 to 1,500 kg/ha.

[0037] If the composition of the invention is used in combination with biostimulants in the form of a liquid for the application thereof by fertigation or foliar application, it is preferably applied in an amount of 0.5 to 20 kg/ha and 0.06 to 1 kg/ha respectively.

EXAMPLES

1. Trial To Obtain and Identify Root Exudates in the Absence of Phosphorus

[0038] In order to characterise in detail the response of crops to phosphorus deficiency and to identify the metabolites exuded by roots that have the greatest influence on phosphorus dynamics in the soil, the Applicant analysed the differential exudate profile of two crop species of agronomic interest, maize and tomato, in the absence of phosphorus. The following is a brief description of the trial to determine the root exudates emitted in the absence of phosphorus.

[0039] The method, similar to that used by other authors (Naveed et al., 2017, “Plant exudates may stabilize or weaken soil depending on species, origin and time”, European Journal of Soil Science) was the same for both maize seeds (variety LG 34.90) and tomato seeds (variety Agora Hybrid F1). The seeds were surface sterilised by washing for 5 minutes in 96% ethanol, followed by 10 minutes in 5% bleach. The seeds were then washed extensively and allowed to hydrate in sterile MilliQ water for 4 hours. For germination, the seeds were placed on a bed of filter paper moistened with sterile MilliQ water. The seeds were left to germinate in darkness for 4 days, after which the seedlings were placed in hydroponic culture trays with the roots immersed in standard Hoagland nutrient solution. Twelve plants were placed in each tray, with three trays (each corresponding to a biological replicate) for the control treatment and three trays for the phosphorus-free treatment. The plants were grown at a temperature and photoperiod of 25° C. and 16 h light/22° C. and 8 h darkness and a light intensity of 4,000 lux on the surface.

[0040] The nutrient solution was replaced with fresh solution every three days and kept aerated at all times by bubbler probes. After 10 days of growth, the plants were subjected to phosphorus depletion treatment. For this, three trays were incubated for three days with modified Hoagland solution without phosphorus and the remaining three trays were incubated with full solution. After incubation, root exudates were obtained.

[0041] The plants were carefully removed from the culture trays and washed with plenty of water, followed by a final wash with distilled water. Plants corresponding to each tray were placed in wide-necked flasks containing 200 ml of MilliQ water, the roots being immersed in the water. The plants were incubated in the flasks for 6 hours. Subsequently, the plants were removed and the insoluble material was removed from the solution by filtering with 0.20 μm filters. The filtered material was flash-frozen in liquid nitrogen and freeze-dried. The dried material obtained was weighed and analysed by gas-mass chromatography after derivatisation with methoxy amine and N-methyl-(trimethylsilyltrifluoroacetamide).

[0042] Table 1 shows the metabolites exuded by the plants and their ratios under phosphorus-free versus control conditions.

TABLE-US-00001 TABLE 1 Increase of metabolites released in the absence of phosphorus. Ratio −P/P Maize Tomato Gluconic acid 6.52 Gluconic acid 8.30 Glyceric acid 3.15 Lactic acid 6.44 Lactic acid 2.72 Glyceric acid 6.27 Glucose 2.23 Erythritol 5.76 Threonic acid 2.16 Serina 4.21 Fructose 1.75 Aspartic acid 3.62 Aspartic acid 1.65 Glucose 3.39 Serina 1.64 Fructose 3.11 Glycerol 1.56 GABA 2.85 Arabinose 1.40 Threonic acid 2.73 Glutamine 1.27 Glutamine 2.34 Arabinose 2.74 Glycerol 1.62

[0043] Based on these results, the 11 matching metabolites in the exudates of both cultures were selected. These metabolites were: gluconic acid, glyceric acid, lactic acid, glucose, threonic acid, fructose, aspartic acid, serine, glycerol, arabinose and glutamine. Each of the metabolites was applied separately at a dose of 1 kg/ha in a pot with 3 kg of soil, maize plants were planted (4 pots per treatment with one plant per pot) and the effect on their dry weight was observed after 6 weeks. The effect of the metabolites was compared with a negative control (no treatment) and a positive control with a conventional phosphate fertiliser (triple superphosphate at a dose of 100 phosphorus fertiliser units —P.sub.2O.sub.5— per hectare). The soil came from an agricultural soil with a sandy loam texture and an assimilable phosphorus content of 0.5 ppm, which is considered a very low level of this element for agricultural practices (Guía práctica de la fertilización racional de los cultivos en España [Handbook of rational fertilisation of crops in Spain], MAPAMA 2009). This level of assimilable phosphorus corresponds to 4.5 kg of P.sub.2O.sub.5 per hectare (considering 30 centimetres of arable soil and an average density of 1,300 kg/m.sup.3, the mass per hectare would be approximately 3,900 tonnes). The total phosphorus level in this soil, including that not available to plants, was 252 ppm (2,251 kg P.sub.2O.sub.5/ha).

[0044] The selected metabolites enhance maize growth to varying degrees, as shown in Table 2 below.

TABLE-US-00002 TABLE 2 Dry biomass of maize plants at 6 weeks of growth. Compound Dry weight (g) Standard error Control 1.11 ±0.06 Gluconic acid 1.77 ±0.03 Glyceric acid 1.93 ±0.05 Lactic acid 1.73 ±0.06 Glucose 1.45 ±0.05 Threonic acid 1.14 ±0.03 Fructose 1.38 ±0.04 Aspartic acid 1.16 ±0.05 Serine 1.31 ±0.02 Glycerol 1.30 ±0.07 Arabinose 1.26 ±0.05 Glutamine 1.55 ±0.07 Triple superphosphate 1.91 ±0.05

[0045] The above results indicate that glyceric acid is the most growth-enhancing metabolite in maize, achieving the same result as conventional phosphate treatment with triple superphosphate.

2. Application of the Fertilising Composition and Combination of the Invention

[0046] Three fertilising compositions in the form of a hydrosoluble powder were prepared according to the invention with the following composition:

[0047] A: 100% by weight of glyceric acid

[0048] B: a combination of 30-80% by weight of glyceric acid and 5-30% gluconic acid, 5-30% lactic acid and 5-30% glutamine;

[0049] C: a combination of 30-80% by weight of glyceric acid and 5-30% glucose, 5-30% fructose and 5-30% glycerol.

[0050] These products (A, B, C) were tested in field trials on maize and tomato plants and compared with a negative control (no treatment) and a positive control of conventional phosphate fertilisation consisting of triple superphosphate (D). The rates and mode of application were as follows:

For maize:

[0051] A: 10.0 kg/ha via fertigation.

[0052] B: 10.0 kg/ha via fertigation.

[0053] C: 10.0 kg/ha via fertigation.

[0054] D: Triple Superphosphate: 100 Phosphorus (P.sub.2O.sub.5) fertiliser units per hectare

For the tomato:

[0055] A: 8.0 kg/ha via fertigation.

[0056] B: 8.0 kg/ha via fertigation.

[0057] C: 8.0 kg/ha via fertigation.

[0058] D: Triple superphosphate: 80 phosphorus fertiliser units (P.sub.2O.sub.5) per hectare

[0059] The treatments significantly improved yield and phosphorus content of maize (Tables 3 and 4) as well as tomato (Tables 5 and 6).

TABLE-US-00003 TABLE 3 Maize yield (Tn grain/ha). Control 8.17 A 9.29 B 10.14 C 9.82 D 10.10

TABLE-US-00004 TABLE 4 Total phosphorus concentration in maize (%). Control 0.16 A 0.25 B 0.31 C 0.29 D 0.31

TABLE-US-00005 TABLE 5 Tomato yield (Tn/ha). Control 44.5 A 49.8 B 53.2 C 51.5 D 52.7

TABLE-US-00006 TABLE 6 Total phosphorus concentration in tomato (%). 2nd bunch Control 0.11 A 0.18 B 0.23 C 0.20 D 0.22

[0060] In order to determine whether the increase in phosphorus content in the treatments studied is due to an increase in the availability of assimilable phosphorus for the plants, phosphorus balances were carried out in the trials with maize and tomato plants.

[0061] In trial 2, the same agricultural soil was used as in trial 1, with an assimilable phosphorus content of 0.5 ppm (corresponding to 1.95 kg/ha phosphorus and 4.5 kg/ha P.sub.2O.sub.5 fertiliser units) and a total phosphorus content of 252 ppm (corresponding to 983 kg/ha phosphorus and 2,251 kg/ha P.sub.2O.sub.5 fertiliser units).

[0062] In treatments A, B and C, no phosphorus fertiliser units were added, as none of the molecules used in these treatments contain this element.

[0063] Taking into account the dry weight of the biomass of maize and tomato plants (see Tables 7 and 8) and the percentage of total phosphorus in the plants (Tables 4 and 6), the kg of phosphorus present in the biomass obtained per hectare can be calculated. As can be seen, the amount of phosphorus in the dry biomass is much higher in all cases than the amount of phosphorus available in the soil. Therefore, the increase in phosphorus content of the plants is necessarily due to an increase in the availability of plant-assimilable phosphorus thanks to the fertilising composition with assimilable phosphorus potentiator.

TABLE-US-00007 TABLE 7 Phosphorus balance in maize plants. Biomass dry weight (Tn/ha) kg of P dry biomass/ha Control 8.36 13.38 A 9.52 23.80 B 10.08 31.25 C 9.88 28.65 D 10.03 31.09

TABLE-US-00008 TABLE 8 Phosphorus balance in tomato plants. 2nd bunch Biomass dry weight (Tn/ha) kg of P dry biomass/ha Control 4.5 4.95 A 5.7 10.26 B 6.1 14.03 C 5.8 11.60 D 6.1 13.42

[0064] In all the tests carried out, the soil used had a pH of 8.4 and a percentage of active limestone of 14%. These conditions are typical of calcareous soils, in which phosphorus precipitates with calcium give rise to calcium phosphates. Thus, in this type of soil, the solubilisation of insoluble phosphorus will not only release assimilable phosphorus for the plants, but also assimilable calcium.