TECHNICAL FIELD

[0001] The present invention relates to a method for improving plant growth and yield, in particular through a method of treating plant material with a nutrient solution containing one or more amino acids and plant nutrients.

BACKGROUND ART

[0002] The following discussion of the background art is intended to facilitate an understanding of the present invention only. The discussion is not an acknowledgement or admission that any of the material referred to is or was part of the common general knowledge as at the priority date of the application.

[0003] Each document, reference, patent application or patent cited in this text is expressly incorporated herein in their entirety by reference, which means that it should be read and considered by the reader as part of this text. That the document, reference, patent application or patent cited in this text is not repeated in this text is merely for reasons of conciseness.

[0004] TM Hildebrandt et al.(“ Hildebrandt’), Amino Acid Catabolism in Plants, Molecular Plant, (2015), 8, 1563-1579 observe that plant cells contain low levels of protein in comparison with animal cells mainly because of the high amount of carbohydrate (cellulose and others) that compose most of a plant’s structure. However, the importance of proteins and amino acids cannot be overlooked. Besides their role as protein constituents, amino acids are also involved in a plethora of cellular reactions and therefore they influence a number of physiological processes such as plant growth and development, intracellular pH control, generation of metabolic energy, or redox power, and resistance to both abiotic and biotic stress. Hildebrandt further observes that current knowledge concerning amino acid catabolism remains rather fragmented.

[0005] CS Dorr et al. (“Don ³ ’), Treatment of soybean seeds of different levels of physiological quality with amino acids, Journal of Seed Science, (2018), 40, 3, 407-414. observe that the physiological quality of soybean seeds and its effect on the performance of plants in the field is a topic that has often been discussed in scientific papers. High physiological quality soybean seeds promote a higher seedling resistance to environmental stresses, adequate plant stand density, higher initial growth, uniformity among plants, and increase of yield components and productivity.

[0006] Dorr treated seeds of different levels of physiological quality with a commercial liquid product containing the following: alanine (1.164%), arginine (0.189%), aspartic acid (1.943%), glutamic acid (3.316%), glycine (0.202%), isoleucine (0.171%), leucine (0.268%), lysine (0.240%), phenylalanine (0.143%), serine (0.179%), threonine (0.188%), tryptophan (0.175%), tyrosine (0.122%), valine (0.288%) with the nutrients nitrogen (11%) and potassium (K2O, 1%).

[0007] In Dorr, seed treatment was carried out by placing the liquid product with a graduated pipette directly in the bottom of polyethylene bags and spread on the sides of the bags up to 15 cm height. Afterward, 0.2 kg of soybean seeds were added inside the polyethylene bag and both liquid products and the soybean seeds were agitated with volume of solution used for seed treatment being 0.8 L per 100 kg of seeds. The seeds were then dried prior to sowing. Physiological performance of soybean seeds was assessed by tests of germination, first germination count, cold, accelerated aging and root and shoot length of the seedling. Dorr found the treatment of soybean seeds with amino acids was found to have no significant effect on seed germination and seedling length regardless of the physiological quality of seed lot. In vigour assessments, a negative effect of seed treatment was identified with increasing doses of amino acids.

[0008] Dorr concluded that seed treatment with amino acids does not promote increases in the physiological performance of seeds and plants nor in productivity.

[0009] It is against this background that the present invention has been developed.

SUMMARY OF INVENTION

[0010] In one aspect, the present invention provides a method of treating plant material comprising treating said plant material with a nutrient solution containing a selected amino acid and plant nutrients.

[0011] In another aspect, the present invention provides a nutrient solution containing a selected amino acid and plant nutrients. [0012] By “plant material” is meant plant seeds, crops and other plant materials, such as cuttings, from which plants can be grown.

[0013] In another aspect, the present invention provides a method of treating plant seeds with a nutrient solution containing a selected amino acid and plant nutrients prior to sowing.

[0014] The method of treating plant material may be applied where the plant material is a crop and treating of the crop comprises or consists of foliar feeding. As understood in the art, in foliar feeding, plant nutrients are delivered through the leaves of the plant forming the crop. Foliar feeding is desired by the Applicant as it addresses issues with, among other issues, soil variability. In preferred embodiments of the invention, amino acid(s) are delivered with other plant nutrients through plant leaves.

[0015] Plant nutrients included in the nutrient solution desirably include one or more, preferably all, of nitrogen, phosphorus, potassium and mixtures thereof (NPK nutrients). Desirably, the nutrient solution also includes other elements, preferably including a group of trace elements selected from the group consisting of sulphur, magnesium, zinc, manganese, copper, iron, boron, molybdenum, cobalt, calcium, silicon and mixtures thereof. Other elements may be included.

[0016] In another aspect, the present invention provides a nutrient solution for treating plant material comprising a selected amino acid or selected plurality of amino acids in aqueous solution with a plurality of plant nutrients which are selected from the groups consisting of:

(A) nitrogen, phosphorus and mixtures thereof; and

(B) a group of trace elements selected from the group consisting of potassium, sulphur, magnesium, zinc, manganese, copper, iron, boron, molybdenum, cobalt, calcium, silicon and mixtures thereof.

[0017] The nutrient solution may be used for seed treatment and/or as a foliar feed for a selected plant or crop. Desirably, the nutrient solution is used both as a seed treatment and foliar feed for a selected plant or crop. In either event, the nutrient solution is applied exogenously to plant material. Foliar feeding may be more efficient than soil feeding alone though a combination of foliar and soil fertilisation may promote superior plant growth. Where used as a foliar feed, the nutrient solution components and content are desirably selected dependent on parameters selected from the group consisting of soil type, crop type, fertility status, growing environment and expected yield potential.

[0018] The nutrient solution may contain a single selected amino acid or a selected plurality of amino acids. In either case, amino acid(s) may be selected from the group consisting of aspartic acid, threonine, serine, glutamic acid, glycine, alanine, cysteine, valine, methionine, leucine, isoleucine, tyrosine, phenylalanine, lysine, histidine, arginine and proline. Cysteine may be excluded due to its reactivity and potential toxicity. Glycine is desirably included in the nutrient solution whether as a single selected amino acid or as a member of a plurality of amino acids.

[0019] A plurality of amino acids may in some embodiments include, in combination, threonine, glycine, alanine, lysine and arginine.

[0020] The amino acids may, in some embodiments, include plant signalling molecules including one or more of serine, proline and leucine. Signalling molecules are involved in biochemical and physiological responses within a plant including germination of seed, photosynthetic regulation and shoot or root development. The amino acids may also be referred to, generally though there may be exceptions, as biostimulants.

[0021] The plant nutrients are conveniently dissolved in aqueous solution with amino acid(s) in a proton rich solution (i.e. containing H ⁺ ), having an acidic range pH due, preferably, to the presence of unreacted phosphoric acid, a plant available source of phosphorus. That is, the nutrient solution desirably has pH in the acidic range. The nutrient solution is expected to be less effective at neutral pH.

[0022] Optionally, the nutrient solution contains nitrogen, phosphorus, potassium, sulphur, magnesium, zinc, manganese, copper, iron, boron, cobalt and molybdenum in aqueous solution. The nutrient solution may contain greater than 3% w/v nitrogen and greater than 10% w/v phosphorus, optionally greater than or equal to 3.5% w/v nitrogen and greater than or equal to 15% w/v phosphorus. Additionally, the nutrient solution may contain greater than 1.5% w/v potassium, optionally greater than or equal to 2.0% w/v potassium. [0023] The nutrient solution may advantageously be prepared as a concentrate which is diluted with water to a dilution ratio, optionally dependent on the plant material, prior to treating plant material. A total content of amino acid(s) in the concentrate nutrient solution is between 1 and 60% w/v, optionally 10-30%w/v, with an upper limit determined based on costs and adverse effects on plants. Thus, in preferred embodiments, the concentrate solution may contain 1 -60% w/v glycine, for example 10% w/v glycine.

[0024] Plant material may be treated with other agricultural chemicals, such as insecticides. Such chemicals may be applied by spraying or coating of plants or seeds. Treated seeds may also be dried following treatment ad prior to sowing.

[0025] The method may be supplemented by further foliar feeding of plant nutrients, for example of NPK to achieve optimum plant nutrition. Soil fertilisation may also be practised in which a balance between foliar and soil fertilisation may be determined with an objective to economically and sustainably establish optimum soil fertility (for example as measured by 100% recommended soil applied fertilisers (RSAF)) also promoting plant growth.

[0026] The method and nutrient solution may be used to treat a range of crops, for example high yield cereal crops, such as rice, corn, barley and wheat; or oil crops, such as rapeseed; and/or their seeds or other plant material from which these crops can be grown. The amount of nutrient solution applied in seed treatment and/or foliar feeding may be selected depending on the plant. For example, corn, cotton, sunflower and pumpkin seeds would tend to require less nutrient solution - for a given nutrient solution composition - than celery and grass pasture seeds.

[0027] In another aspect, the present invention provides a method of fertilising a farmed area comprising the step of applying a fertiliser containing a nutrient solution comprising a selected amino acid or selected plurality of amino acids and plant nutrients to a crop growing in the farmed area, wherein said fertiliser is applied to said crop by foliar feeding.

[0028] Preferably, said crop is grown from seeds which have been treated as described above. [0029] In the case of seeds, seeds may be treated with the nutrient solution at a selected time before sowing. Desirably, such seed treatment is conducted before sowing, for example at least one day before sowing, at any time between harvest and sowing. Treatment of clean and not dusty seed is preferred to avoid stickiness and absorption of nutrient solution reducing seed uptake of the nutrient solution.

[0030] Without wishing to be bound by theory or objective, the amino acid containing nutrient solution desirably increases nutrient availability, in particular phosphorus and trace elements, overcoming limited amounts of plant available phosphorus during early germination. That is, in the case of seeds, about 70% of phosphorus is as phytic acid which is unavailable to the plant during early germination. The amino acid containing nutrient solution is intended to increase rhizosphere activity and exudation of organic acids releasing soil-based phosphate bound to calcium (in alkaline soils) or soil-based phosphate that is bound to metals such as aluminium, iron and manganese in acid soils. The presence of amino acids enhances nutrient availability and has positive consequences in terms of resultant faster root system growth following germination, this protecting plants from disease. Slower root system growth, for a given plant, is associated with higher disease susceptibility.

[0031] In summary, the method and nutrient solution combining or integrating the action of amino acid(s) and plant nutrients promote the biological properties of plants - such as rice, corn, wheat and rapeseed - in either seed treatment or foliar feeding (or preferably both seed treatment and foliar feeding) and are expected to have a significant effect on improving quality, yield and consequential economic benefits. The gains may be such as to reduce requirements for fertilising treatments during plant growth, thus reducing overall costs and carbon emissions due to excessive fertilisation events.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0032] Further features of the method and nutrient solution for treating plant material of the present invention are more fully described in the following description of several non-limiting embodiments thereof. This description is included solely for the purposes of exemplifying the present invention. It should not be understood as a restriction on the broad summary, disclosure or description of the invention as set out above. [0033] Those skilled in the art will appreciate that the invention described herein is susceptible to variations and modifications other than those specifically described. The invention includes all such variation and modifications. The invention also includes all of the steps, features, formulations and compounds referred to or indicated in the specification, individually or collectively and any and all combinations or any two or more of the steps or features.

[0034] The invention described herein may include one or more range of values (e.g. concentration etc). A range of values will be understood to include all values within the range, including the values defining the range, and values adjacent to the range which lead to the same or substantially the same outcome as the values immediately adjacent to that value which defines the boundary to the range.

[0035] Other definitions for selected terms used herein may be found within the detailed description of the invention and apply throughout. Unless otherwise defined, all other scientific and technical terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which the invention belongs. The term “active agent” may mean one active agent, or may encompass two or more active agents.

[0036] Any manufacturer’s instructions, descriptions, product specifications, and product sheets for any products mentioned herein or in any document incorporated by reference herein, are hereby incorporated herein by reference, and may be employed in the practice of the invention.

[0035] In preferred embodiments, plant seeds and plant leaves (foliar feeding) are treated with a nutrient solution containing a selected amino acid and plant nutrients as described above. The amino acids may be selected from the group consisting of aspartic acid, threonine, serine, glutamic acid, glycine, alanine, cystinol, valine, methionine, leucine, isoleucine, tyrosine, phenylalanine, lysine, histidine, arginine and proline. Glycine is particularly desirably present within the nutrient solution as described for Examples 1 to 5 below. Glycine addition to the nutrient solution may be in the range 1 to 60% w/v with 10% w/v exemplified below. Other components of the nutrient solution, mixed in water on a litre basis are described below. [0036] Further description of the method of treating plant material by seed treatment and foliar feeding will be made with reference to the following examples where glycine was selected as a preferred amino acid. It will be understood that, in other embodiments, amino acids other than glycine may be used.

Examples 1 to 4 - Seed Treatment

[0037] In these examples, seeds were treated with a nutrient solution concentrate available under the Trade Mark ‘BSN Superstrike’ from RLF Agtech Ltd, Perth, Australia, with components including 10% w/v glycine and as follows:

[0038] The nutrient solution is proton rich, containing unreacted phosphoric acid. The nutrient solution should not be mixed with alkaline copper fungicides or inoculants.

Example 1 - Rapeseed

[0039] Rape seeds were treated according to the following regime:

Treatment 1 : Mix 2 kg of rape seeds with 10ml nutrient solution and 10ml water. Treatment 2: Mix 2kg of rape seeds with 10ml nutrient solution with the amino acid glycine (10% w/v glycine in the nutrient solution) and 10ml water.

Treatment 3: Control - no treatment

[0040] The seeds were then sown in the same area with consistent field management in terms of sowing, weeding, fertilisation, irrigation, pest control and so on. A comparison between the different treatments was made at the flowering stage of the rape seed.

Table 1 : Comparison of Indexes of different treatments at flowering stage of rapeseed

[0041] Compared with Treatment 2, the rapeseed treated by nutrient solution with glycine had thicker stems and a large number of flowers supporting seed setting and yield increase over the treatment with nutrient solution alone (Treatment 2) and control (Treatment 3). In addition, the treated rapeseed had more developed roots, higher plants, more hypertrophic leaves, thicker stems, denser green leaf colour and more flowers than the control rapeseed.

Example 2 - Corn

[0042] Corn seeds were treated according to the following regime:

Treatment 1 : Mix per 1 kg of corn seeds, 5ml nutrient solution and 10ml water, coat with insecticide, dry and sow seeds.

Treatment 2: Mix per 1 kg of corn seeds with 5ml nutrient solution with the amino acid glycine (10% w/v glycine in the nutrient solution) and 10ml water. Treatment 3: Control - no treatment

The seeds were then sown in plots in the same area with consistent field management in terms of sowing, weeding, fertilisation, irrigation, pest control and so on. A comparison between the different treatments was made of corn seedlings with 10 plants from each treatment being sampled.

Table 2: Comparison of Indexes of different treatments of corn seeds

[0043] Corn seed treated by the amino acid containing nutrient solution was found to have a more developed root system, taller plants, thicker stems, more dense and green leaf colour and improved growth than corn seed of the control.

[0044] At harvest time, some five months after day 1 , corn yield was measured and the impact of the various treatments on yield measured. The results are provided in Table 3 below:

Table 3: Comparison of Corn Yield for Different Treatments [0045] The theoretical yield of the corn grown under control conditions was 15366.9 kg/ha. The corn treated with the nutrient solution (without amino acids) had a yield of 16082.25 kg/ha, an improvement of 4.65% compared with the control.

[0046] The theoretical yield of the corn treated with the nutrient solution (with amino acids, here glycine) is 16768.8 kg/ha, an increase of 9.12% compared with the control demonstrating an advantage in increased yield and income.

Example 3 - Spring Wheat

[0047] Spring wheat seeds were treated according to the following regime:

Treatment 1 : Mix per 1 kg of spring wheat seeds, 5ml nutrient solution and 10ml water, coat with insecticide, dry and sow seeds.

Treatment 2: Mix per 1 kg of spring wheat seeds with 5ml nutrient solution with the amino acid glycine (10% w/v glycine in the nutrient solution) and 10ml water, dry and sow seeds.

Treatment 3: Control - no treatment

[0048] The seeds were then sown in plots in the same area with consistent field management in terms of sowing, weeding, fertilisation, irrigation, pest control and so on. A comparison between the different treatments was made of spring wheat seedlings.

Table 4: Comparison of Indexes of different treatments of spring wheat seeds [0049] Spring wheat seeds treated by the amino acid containing nutrient solution was found to have a more developed root system, more effective tillers, taller plants, thicker stems, more green leaves, fuller seeds and heavier 100 grain weight compared with spring wheat seeds of the control with advantages in increasing yield and income from production.

Example 4 - Rice

[0050] Rice seeds were treated according to the following regime:

Treatment 1 : Mix per 1 kg of rice seeds, 5ml nutrient solution and 10ml water, coat with insecticide, dry and sow seeds.

Treatment 2: Mix per 1 kg of rice seeds with 5ml nutrient solution with the amino acid glycine (10% w/v glycine in the nutrient solution) and 10ml water, dry and sow seeds.

Treatment 3: Control - no treatment

[0051] The seeds were then sown in plots in the same area with consistent field management in terms of sowing and late fertilisation management. A comparison between the different treatments was made of rice seedlings.

Table 5 Comparison of indexes at rice tillering stage under different treatment conditions

[0052] The rice seedlings treated with nutrient solution and nutrient solution with amino acids showed improved performance compared to the control rice seedlings, the treatment with nutrient solution containing the amino acid being best. The rice seedlings had more tillers, stronger plants and dark green leaves. [0053] The rice seedlings also immediately entered the leaf break stage with rice leaves treated by the nutrient solutions being flat and wide which is conducive to more photosynthesis and nutrient production.

Table 6 Comparison of indexes at rice breaking stage under different treatment conditions

[0054] Rice yield was also measured for the different treatment conditions showing a significant increase in yield and income.

Table 7 Comparison of rice yield under different treatment conditions

[0055] Embodiments of the method also involve foliar feeding of the crop with the nutrient solution of the invention. Foliar Feeding

Example 5 - Soybean Line

[0056] An early maturity, free standing soybean line (PI595362 sourced from the University of Missouri, USA) with shallow and fibrous root system, suitable for short duration pot study, was selected for foliar treatment. The soybean was grown in pots filled with 4 kg of well-drained soil sourced from UWA Research Station, Pingelly with pH >6.5 (CaCh). Sub-optimal soil fertility was induced by adding 80% conventionally recommended soil applied fertilisers (80% RSAF) to pots. The seed inoculated with Noduator (granular legume inoculant available from BASF Australia) were sown in pots.

[0057] The replicates were grown for 80 days after sowing (DAS) in a controlled environment room (13 hours per day/25°C and 11 hours night/17°C) and maintaining moisture at 13% (v/w) for the duration of the study.

[0058] The pots were sprayed twice (1 L/ha foliar feed each time) with a nutrient solution - as available under the trade mark Legume Plus Max (LPM) from RLF Agtech Pty Ltd - under 1 ) a control condition using LPM without glysine and under 2) a test condition using LPM with glycine introduced. The concentrated nutrient solution, prior to dilution with water (1 part concentrated nutrient solution to 99 parts water) and foliar spraying, contained 10% w/v glycine.

[0059] The LPM concentrated nutrient solution containing glycine (10% w/v as in the other Examples) is a proton rich aqueous solution comprising unreacted phosphoric acid comprising the following plant nutrients (composition in % w/v):

Nitrogen 3.5

Phosphorus 15

Potassium 2.0

Sulphur 2.3

Magnesium 1.0

Zinc 4.0

Manganese 1 .5

Copper 0.10 Iron 0.05

Boron 0.25

Cobalt 0.03

Molybdenum 0.04

[0060] The water diluted nutrient solution was sprayed twice (1 L/ha each time), followed by a spray of nitrogen fertiliser (10% of total N used in RSAF) at 40, 45 and 50DAS respectively to provide a foliar feed to plants grown in pots with suboptimum soil fertility (80% RSAF). The controls were sprayed with diluted LPM solution (1 part LPM to 99 parts water) only, i.e. not containing glycine. It will be understood that the number and timing of treatments during plant growth is likely to be important for optimising plant growth and yield.

[0061] The harvested plants (harvest at 80 DAS) were separated into shoot and root, dried at 60°C to determine the weight and the relative value (% harvested dried plant parts at suboptimal/optimum) of root, shoot and plant dry weight respectively. The addition of glycine with plant nutrients improved LPM performance by enhancing relative root growth (17%), shoot growth (10%) and plant growth (13%) over use of LPM alone.

[0062] It will be understood that soybean seeds could also be treated by a nutrient solution either as described for Examples 1 to 4 or as described for Example 5. The same or different nutrient solutions may be used for seed treatment and foliar feeding.

[0063] Optimum plant nutrition may require a balance of foliar feeding and addition of NPK and other plant nutrients by soil fertilisation to achieve optimum RSAF. However, the present invention allows the amount of soil fertilisers to be reduced and has benefits in terms of reducing the costs of chemical fertiliser inputs (e.g of superphosphates etc.) and reducing the associated carbon footprint which assists more sustainable agriculture.

[0064] The disclosed methods and nutrient solutions also promote the biological properties of high yield crops, such as rice, corn, wheat and rapeseed, and are expected to have a significant effect on improving quality, yield and consequential economic benefits for those crops.

[0065] Throughout this specification, unless the context requires otherwise, the word "comprise" or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.