AU2002300060B2 - Fertilizer composition including fulvic acid - Google Patents

Description

FERTILIZER COMPOSITION INCLUDING FULVIC ACID This invention relates to fertilizer compositions and methods for their production and use. Such compositions contain important nutrient elements and compounds for employment in soil fertilisation. In such manner, plant growth and development may be promoted.

At the present time, most fertilizers in conventional use are chemical fertilizers, not natural products. For example, as US 5912398 explains, phosphorus fertilizers are produced by chemical treatment of mined phosphate ores. The chemical conversion of mineral phosphate ore into phosphate fertilizer is an energy intensive process involving high temperature leaching of phosphate ore. The leaching process generates contaminants and the resultant fertilizers are often over-utilised.

As an alternative to such chemical fertilizers have been proposed biological fertilizers which are naturally occurring materials or derived from naturally occurring materials. Various biological fertilizer compositions are available, one being the subject of the Applicant's Australian Patent Application No. 18362/01 filed February 8, 2001. That composition is derived by at least partial microbial digestion of: fertilizer components adjusted in proportion to give the desired NPK analysis; a source of phosphate an adsorbent material; biomass derived from a microbial inoculate; a carbon source suitable to sustain growth of digestion microorganisms.

An objective of using fertilizer compositions is to promote plant growth and plant nutrition because the quality of food is directly related to nutrition received by plants. The balance of that nutrition between the primary minerals nitrogen, phosphorus, potassium and calcium may be critical to the end result for a plant in terms of yield and the nutritional value of the edible part of the plant.

Increased plant nutrition requires increase of the rate of photosynthesis which forms the primary sugars needed by a plant to grow and reproduce itself.

By increasing sugar production within the plant cell, a high energy food product can be produced because sugars are a primary source of energy required for life.

The element phosphorus is important to control of sugar production.

Therefore, higher levels of phosphorus in plants assist in increasing the rate of photosynthesis and sugar production. A major limitation when fertilising plants to increase sugar production is the rate of uptake of phosphorus and other nutrients by a plant. That rate may be limited because the fact that a fertilizer is applied to a plant or leaves of a plant does not mean that all of the nutrient is taken up and metabolised by the plant. In the case of foliar spraying, much of the spray may be lost, falling off leaves onto soil without any uptake of the nutrient from this "lost" spray.

It is therefore an object of the present invention to provide a fertilizer composition that facilitates plant nutrient uptake rate.

With this object in view, the present invention provides a phosphorus containing fertilizer composition containing a fulvic acid in effective amount to increase plant cell uptake of at least one nutrient selected from the group consisting of nitrogen, phosphorus, calcium, potassium and any combination of these.

Such a fertilizer composition may be in liquid or solid form with a desired NPK and calcium analysis, The NPK and calcium analysis may be made up by conventional compounds such as potassium phosphate, potassium sulphate, lime, calcium nitrate, urea and ammonium compounds such as ammonium nitrate and diammonium phosphate. Biologically acceptable compounds which should not contain minerals in the chloride form may also be used for achieving the desired NPK and calcium analysis. The chlorine tends to kill the micro-organisms that live on the surface of the leaf. This allows disease into the plant. Also, all chlorides are salts and salts kill or suppress microbial activity. The phosphorus analysis is advantageously higher than that of nitrogen, potassium or calcium.

The ratio of phosphorus to calcium is important to the results achieved with a ratio in the range of 1:1 and 3:1, being most effective on plant growth and sugar levels. This ratio of phosphorus to calcium needs to be achieved without the formation of tri-calcium phosphate which precipitates and preferably maintaining a pH in the solution of 1.8-2.2. The pH of the base product is influential to the final pH of the spray solution at the time of application. The lower the pH of the initial product the more water that is required to increase the pH of the spray solution so as not to burn leaf tissue or create excessive shock in the plant.

The pH in the range of 1.8 2.2 minimises the precipitation of humic acids and the resulting spraying and filtration problems that occur with having a solid component in a product designed for spray application.

The advantage achieved with the fertilizing composition of the present invention is maintaining the phosphorus and calcium in solution without forming tricalcium phosphate and forming insoluble precipitates. A ratio of 3:1 phosphorus to calcium can be achieved readily by reducing the pH to 0.5 1 range. However, such a low pH is detrimental to plant growth.

By creating fulvic acid by an acid alkali reaction, a level of heat in the solution of between 20 0 C and 70 0 C is generated which allows total dissolution of all the added solids. The heat also disperses the added oil more completely which then interacts with the fulvic acids protecting or chelating the calcium preventing it from forming insoluble tricalcium phosphate.

The addition of the oil increases the chelating effect of the fulvic acids which then allows more calcium to be added to the solution without precipitation then would normally be possible.

The 2:1 ratio of phosphorus to calcium is preferred as being most effective on plant growth and sugar levels is not normally achievable in solution without some other mechanism being present to prevent the formation of tricalcium phosphate precipitation.

In an aqueous solution at pH 2.0, the formation of tricalcium phosphate occurs at very low concentrations and ratios. Eg 5% phosphorus and calcium. In the composition and method of the present invention it is possible to prevent the precipitation of tricalcium phosphate at much higher concentrations such as 9% phosphorus and 4% calcium.

Microorganisms which aid plant nutrient uptake may be included within the composition. These microorganisms may be introduced to the fertilizer composition in the dormant form. Suitable microorganisms are organic material decomposing microorganisms found, for example, in liquid extracts from sewage sludge or compost worm castings. Grain industry waste or other biologically active industrial waste may also include suitable microorganisms.

In liquid form, such composition may be utilised as a foliar spray for plants with the fertilising composition containing fertilizer components in aqueous solution. Such solution may have pH in the acid range with pH not varying beyond bounds at which plant damage occurs. A pH of 0.5 to 3.0 more preferably pH 1-2, is acceptable in a concentrate which may be diluted as necessary to minimise risk of plant damage.

The quantity of fulvic acid is expected to range between 1 and 20% by volume of a liquid fertilizer composition, the amount being selected to increase plant uptake of nutrients such as nitrogen, phosphorus, calcium, potassium and any combination of these. Increase of phosphorus uptake may be most desirable in view of the apparent dependence of photosynthetic rate on phosphorus uptake.

Sources of fulvic acids, organic acids having a short chain carbon group produced by microbial breakdown of plant residues, and other organic materials, may include soils, peat and coal. A water soluble fraction of fulvic acids suitable for inclusion in a liquid fertilizer may be produced by a leaching process involving an alkaline-acid reaction, which separates the soluble carbon fraction being humic acids and fulvic acids from insoluble humins. The major difference between humic acids and fulvic acids is the length of the carbon chain and hydrogen absorbing capacity. Humic acids have an exchange capacity or hydrogen absorbing capacity of 400-800 meq/gm, are soluble in alkaline solutions and have long chain carbon groups. Fulvic acids are water soluble at all pH levels but solubilise better at low pH values and have an exchange capacity of 900-1400 meq/gm. Fulvic acids are very reactive, functioning as powerful chelators of minerals including nutrient minerals such as calcium and potassium.

Fulvic acid containing material, or a material from which fulvic acids may be derived in a leaching process, for example soil, peat or coal, is subjected to a leach reaction of this kind to liberate fulvic acids. However, it is not intended to preclude other sources of fulvic acids from the fertilizer composition of the invention.

The role of fulvic acids, without wishing to be bound by any theory, may reside in their capacity to alter the permeability of walls of plant cells to enable increased uptake of applied nutrients over a situation where fulvic acids are not present. In this way, foliar sprays and fertilizers containing these fulvic acids may result in increased nutrient uptake capacity of plants.

A fertilizer composition of the invention may allow application of calcium and phosphate in such a form that enables calcium distribution to occur in desired parts of the plant thus potentially increasing product shelf life by reducing the risk and incidence of bruising. Calcium phosphate may advantageously be present in solution within the fertilizer composition as monocalcium phosphate. In that regard, it is advantageous to supply calcium to plants in monocalcium phosphate form, the mobile phosphate allowing the more immobile calcium ions to move throughout the plant.

The fertilizer composition may be supplied in concentrate or diluted form, the dilution being with water or water containing additives which may facilitate plant growth and nutrition.

Such aqueous solutions may be applied to an area to be fertilised by any suitable technique. For example, the fertilizer composition may be applied by low water volume applicators such as misters and boom sprays commonly used in broad acre agriculture. However, the fertilizer composition of the invention may also be applied on a smaller scale.

The fertilizer composition of the present invention may be a foliar spray or other liquid having analysis (percent by volume) as follows: Nitrogen 2-10% Phosphorus 6-15% Potassium 2-10% Calcium 1-8% Fulvic acid 1-20% Water 1-40% Vegetable oil 1-10% In tests conducted using a fertilizer composition of the present invention, sugar level increases measured in Brix by use of a refractometer have been recorded. Increases of up to 4% have been noted on wheat and clover production. Such increases remained sustained 14 days after application.

Example I By way of example, a liquid fertilizer compost and foliar in accordance with the invention may be prepared as follows.

To manufacture a fulvic acid, 301 of vegetable derived oil is added to 8001 of water followed by 70kg of potassium hydroxide, 20kg of burnt lime and finally 100kg peat. The resulting mixture is agitated for a period of 10 20 hours and the 1001 of phosphoric acid is added and the pH adjusted to 5.5. The resulting fulvic acid solution is dark brown in colour.

6001 of fulvic acid are admixed with 1001 of water, 601 of phosphoric acid, 175kg diammonium phosphate and 230kg of calcium nitrate resulting in a solution with a pH in the range of 1.8 2.2.

In field trials using the product of Example I applied at the rate of 4 litres per hectare. Improvements were seen in sugar levels and yield.

Example II A trial was conducted and a clover based lawn the lawn consisting of mainly lotus clover. The lawn was spread twice with a separation of 21 days with the trial running for a period of 34 days.

The following table shows the results from the above trial.

CONTROL TREATED Average height on 2 August 2001 5-14 inches 18-25.5 inches Average height on 25 August 2001 10-14 inches 30-33 inches Average sugar levels 5.94 7.19 Average sap conductivity levels 8.11 10.09 Number of days that the treated area had 14 out of 18 days higher sugar levels than control Number of days that the treated area had 15 out of 18 days higher sap conductivity levels than the control Example III In another example a pasture was sprayed twice with a 31 day separation.

The following table shows biomass calculation as the pastures having been performed by mowing areas of 2.6 x 0.4m after 72 days from the commencement of the trial.

Control Treated Site 1 1.73kg 1.73kg Site 2 1.78kg 2.23kg Site 3 1.51kg 2.08kg Average 1.64kg 2.01kg Wet Weight 15.8t/ha 19.3t/ha Dry Weight 3.2t/ha 3.9t/ha Increase 22% The biomass calculations using a moisture content of 80% for the samples show an increase of 740kg/hectare or 22% increase in the dry biomass.

Modifications and variations may be made to the fulvic acid containing fertilizer composition of the present invention by skilled readers of this disclosure.

Such modifications and variations are within the scope of this invention.

Claims (9)

1. A phosphorus containing fertilizer composition containing: c an effective amount of fulvic acid to increase the plant cell uptake of at least one or a combination of nutrients selected from the group consisting of nitrogen, phosphorus, calcium and potassium and wherein the phosphorus Sanalysis is higher than that of the nitrogen, calcium or potassium.

2. The phosphorus containing fertilizer composition of claim 1, wherein the SNPK and calcium analysis is made up by a compound selected from the group, including potassium phosphate, potassium sulphate, lime, calcium nitrate, urea, and ammonium compounds, including ammonium nitrate and diammonium phosphate.

3. The phosphorus containing fertilizer composition of claim 2, wherein the compounds are biologically acceptable and not in the chloride form.

4. The phosphorus containing fertilizer of any one of the preceding claims with a phosphorus to calcium ratio in the range of 1:1 to 3:1. The phosphorus containing fertilizer of any one of the preceding claims, wherein fertilizing components are in aqueous solution.

6. The phosphorus containing fertilizer of claim 5, wherein the pH is in the range of 0.5 3.

7. The phosphorus containing fertilizer of any one of the preceding claims with fulvic acid in the concentrations of 1 to 20% by volumrne of a liquid fertilizer composition.

8. The phosphorus containing fertilizer of any one of: the preceding claims wherein the calcium is in the form of monocalcium phosphate. 00 O 9. The phosphorus containing fertilizer of any one of the preceding claims in Sthe form of a liquid spray having the analysis of: e Nitrogen 2 oo Phosphate 6-15% Potassium 2-10% Calcium 1 8% IDFulvic acid 1 Water 1 Cc Vegetable oil 1-10%

10. A method of fertilizing, including the administration to an area to be fertilized, a composition as claimed in any one of the preceding claims.

11. A method of manufacturing a phosphorus containing fertilizer according to any one of claims 1 to 9, including the steps of extracting fulvic acid by the steps including: i) mixing a predetermined amount of vegetable derived oil with water; ii) adding a predetermined amount of potassium hydroxide; iii) adding a predetermined amount of burnt lime; iv) adding a predetermined amount of peat v) agitating the resulting mixture for 10 20 hours to produce a fulvic acid extract; vi) adjusting the pH of the solution to the desired level by the addition of phosphoric acid; and mixing a working fertilizer composition by: i) mixing a predetermined amount of fulvic acid extract; ii) adding a predetermined amount of phosphoric acid; iii) adding a predetermined amount of diammonium phosphate; iv) adding a predetermined amount of calcium nitrate. THE ERA FARMING COMPANY PTY LTD WATERMARK PATENT TRADE MARK ATTORNEYS P19930AU00