GB2314557A - Plant nutrient formulations - Google Patents

Abstract

According to a first aspect, a plant nutrient formulation, and in particular a hydroponics formulation, comprises a synergistic mixture of: (1) An agriculturally acceptable surfactant, such as cetrimide, with either or both of the following components: (2) An amine compound selected from secondary amines, tertiary amines and hydroxylated amines, e.g. triethanolamine, (3) A branched chain amino compound, e.g. an amino acid such as glycine, together with other conventional plant nutrients and additives, as desired. In a second aspect, a plant nutrient formulation, and in particular a hydroponics formulation, comprises (1) magnesium sulphate and (2) a calcium salt being calcium glycerophosphate, calcium hypophosphite or a combination thereof, together with other conventional plant nutrients and additives, as desired.

Description

"PLANT NUTRIENT FORMULATIONS" FIELD OF THE INVENTION The present invention relates to plant nutrient formulations for use in agriculture and horticulture, and in particular for use in relation to hydroponics.

BACKGROUND OF THE INVENTION Delivery of appropriate levels of nutrients such as minerals to plants can pose difficulties, especially in relation to hydroponics. Iron deficiency can be a particular problem, resulting in yellowing of foliage.

We have now found that particular combinations of compounds increase the efficiency of delivery of nutrients to the plants. Accordingly, in a hydroponics situation, lower concentrations of feed-stock can be used, and there is a lower run-off of waste. An added advantage is a decreased risk of disease or foliar damage, such as tipburn.

Amino acids have been used as a nitrogen source in plant nutrient formulations.

However, as far as the present inventor is aware, amino acids have not been used in such formulations in conjunction with compounds such as cetrimide, which are both wetting agents and antimicrobial agents.

Similarly, it is known to use glycerophosphate and hypophosphite salts of calcium in fertilizers (see eg "New Phospatic Fertilizers" by J R Ansiaux, FAO Soils Bulletin, 1978,No 37, pp 145-148; "Effect of inoculation and spraying with different phosphorus compounds on nodulation and yield of bush sitao (Vigna sinensis var.

sesquipedalis frunv)" by V Iswaran and C V Adajar, Philippine Journal of Plant Industry, 1974, vol 39(2), pp 115-118; USSR Patent Specification No 1368572 in the name of Kaza Phosphorus Ind (filed 1st July 1986)). However, it has not previously been known to combine those calcium salts with magnesium sulphate in one-part plant nutrient formulations.

DESCRIPTION OF THE INVENTION According to a first aspect of the invention, a plant nutrient formulation, and in particular a hydroponics formulation, comprises a synergistic mixture of: (1) An agriculturally acceptable surfactant, such as cetrimide, with either or both of the following components: (2) An amine compound selected from secondary gamines, tertiary amines and hydroxylated amines, (3) A branched chain amino compound, together with other conventional plant nutrients and additives, as desired.

Preferably, all of components (1) to (3) are present.

Cetrimide is a quaternary ammonium cationic detergent, consisting principally of a mixture of alkyltrimethylammonium bromides. It is a known wetting agent, and has previously been utilised for its antimicrobial properties. However, it has not previously been used in fertilizers or plant nutrient formulations. In the compositions of the present invention, it is utilised for its nutrient dispersing properties, and to enhance absorption of nutrients in the composition by the root hairs of plants. Its antimicrobial properties are also of benefit, as the present compositions preferably comprise lower levels of sulphates than prior art compositions. The high levels of sulphates in prior art compositions have antimicrobial properties, whereas the lower levels in the present compositions require the presence of the added surfactant as an antimicrobial agent. The formulations of the present invention preferably comprise 50-150 mg/l cetrimide, and more preferably about 100 mg/l.

The amine compound (2) is preferably triethanolamine. Triethanolamine is an organic solvent and intermediate in the manufacture of surface active agents. It will preferably be present in a concentration of 4.5-6.5 mg/l, and more preferably in a concentration of about 5.5 mg/l.

Incorporation of triethanolamine in the hydroponics solutions of the present invention may have at least two advantageous effects. Firstly, it is capable of providing a buffer against pH change. At the concentrations existing in the final hydroponics solutions, it is expected to have a fairly small but still appreciable buffering effect. Secondly, it may reduce the rate of abscission (dropping) of young fruit. Minute amounts of the triethanolamine salt of a synthetic auxin (2,4,5-TP) are known to reduce abscission. If the triethanolamine in the present hydroponics formulations combines with auxins already in the plant, then a similar effect may be observed in fruiting plants.

The branched chain amino compound (3) is preferably an amino acid, in particular glycine. Glycine is a simple amino acid, which is known for use as a human and animal nutrient. Amino acids such as glycine can improve plant growth through their provision of nitrogen.

The concentrations of several amino acids, including glycine, increase in plant tissues during the initiation of shoots. This suggests that, after the glycine in the hydroponics solution is taken up by the plant, it could increase branching of shoots.

Furthermore, glycine is known to increase callus formation in tissue culture media.

The relevance of this to solutions around intact roots is uncertain, but the glycine may possibly have the effect of increasing root branching.

Glycine is also capable of forming chelation complexes with trace elements. This affords some protection against chemical reactions that would otherwise remove the trace elements from solution. This chelation effect is particularly useful with respect to iron.

The present formulations will preferably comprise 20-25 mg/ 1 of the branched chain amino compound such as glycine, and more preferably about 21 mg/l of glycine.

In the present formulations, the amine compound (2) and the branched chain amino compound (3) assist in bonding or chelating to metals, thus enhancing delivery of the metals to plants.

In compositions which have been utilised to date, a pH of about 5.5-6.5 is necessary for delivery of plant nutrients, in particular metals such as iron or magnesium. By utilising a branched chain amino compound and a secondary, tertiary or hydroxylated amine in the formulations, the nutrients in the formulation can be made available to plants over a far wider pH range.

The various components of the formulation (ie the surfactant; secondary, tertiary or hydroxylated amine; and branched chain amino compound) have a synergistic effect when used in combination, and greatly enhance the availability of nutrients to plants.

In particular, iron can be incorporated in the formulations in lower levels than previously, whilst still avoiding the foliage yellowing caused by iron deficiency.

Research has shown that spraying plant shoots with methanol/ glycine mixtures can lead to 100% increases in growth under high-light conditions. Apparently, methanol provides some carbon and the glycine is a nitrogen source. However, the effect may be even more specific, in that it lasts long after it would have been expected that the applied methanol and glycine would have been used up by the plant. When the same solution was applied to plants under artificial light, plant damage resulted.

This damage is preventable by including glycerophosphate in the solution.

Accordingly, a combination of glycine with glycerophosphate can increase plant growth in hydroponics solutions, whilst helping to prevent plant damage. Part of the increase in plant growth probably results from increase in the turgidity of the plant tissues under drying conditions. This increase in turgidity allows the stomata to remain open for longer and thus allows more carbon dioxide into the plant, hence allowing the production of greater quantities of photosynthesis products.

In a second aspect of the invention, a plant nutrient formulation, and in particular a hydroponics formulation, comprises (1) magnesium sulphate and (2) a calcium salt being calcium glycerophosphate, calcium hypophosphite or a combination thereof, together with other conventional plant nutrients and additives, as desired. Calcium and magnesium are important plant nutrients. In prior art compositions, magnesium is generally used in the form of magnesium sulphate, and calcium in the form of calcium nitrate. In order that these important plant nutrients can be delivered at the highest possible tolerance levels, they are delivered separately to prevent precipitation (in the form of gypsum).

In the present formulations, calcium is used in the form of calcium glycerophosphate or calcium hypophosphite. When combined with magnesium sulphate, there is no problem with gypsum formation. Accordingly, the magnesium and calcium components can be delivered together, in a single liquid formulation. All of the required plant nutrients are freely available in the one liquid.

The formulations of the present invention are well-balanced, and form very little (if any) precipitate. The amount of magnesium sulphate in the hydroponics formulation is preferably 200-300 mg/l, and in particular 250 mg/l. The calcium salt(s) are preferably present in amounts of 50-400 mg/l. Particularly preferred are formulations comprising both calcium glycerophosphate and calcium hypophosphite, the total amount of both salts being 125 to 350mg/l.

The invention will now be further described with respect to the following examples, which are illustrative but not restrictive of the present invention. Although not limited to such use, the BLOOM formulations of Examples 1 and 5 are specially formulated for plants at the flowering/fruiting stage, whereas the GROW formulations of Examples 2 and 4 are specially formulated for plants at the active growth stage.

EXAMPLE 1 BLOOM A: To make 1000 litres of the concentrate, BLOOM A, the following amounts are dissolved in about 850 litres of warm water then, when all is in solution, made up to 1000 litres.

1.0 kg cetrimide 8.6 kg ammonium nitrate 20.2 kg potassium nitrate 130 kg calcium nitrate tetrahydrate 1.3 kg FeEDTA or 2.8 kg FeEDDHA (both of which are iron chelates) On standing, this solution may throw a slight brown precipitate. This is easily resuspended by shaking.

BLOOM B: To make 1000 litres of the concentrate, BLOOM B, the following amounts are dissolved in about 800 litres of warm water then, when all is in solution, made up to 900 litres.

1.0 kg cetrimide 20.2 kg potassium nitrate 79.0 kg monopotassium phosphate 34.8 kg potassium sulphate 50.7 kg magnesium sulphate heptahydrate To this 900 litres of solution, 100 litres of Trace Element Concentrate (see Example 3) is added.

The BLOOM A formulation, and the BLOOM B plus Trace Element Concentrate formulation, are packaged separately, to be marketed as a two-component mix. In use, the two separate formulations are applied to the plants at around the same time, diluted by a factor of 50 ml BLOOM A plus 50 ml BLOOM B/Trace Element Concentrate to 10 litres water.

EXAMPLE 2 GROW A: To make 1000 litres of the concentrate, GROW A, the following amounts are dissolved in about 850 litres of warm water then, when all is in solution, made up to 1000 litres.

1.0 kg cetrimide 8.6 kg ammonium nitrate 55.6 kg potassium nitrate 130.0 kg calcium nitrate tetrahydrate 1.3 kg FeEDTA or 2.8 kg FeEDDHA (both of which are iron chelates) On standing, this solution may throw a slight brown precipitate which is easily resuspended by shaking.

GROW B: To make 1000 litres of the concentrate, GROW B, the following amounts are dissolved in about 800 litres of warm water then, when all is in solution, made up to 900 litres.

1.0 kg cetrimide 55.6 kg potassium nitrate 27.2 kg monopotassium phosphate 49.3 kg magnesium sulphate heptahydrate To this 900 litres of solution, 100 litres of Trace Element Concentrate (see Example 3) is added.

The GROW A formulation, and the GROW B plus Trace Element Concentrate formulation, are packaged separately, to be marketed as a two-component mix. In use, the two separate formulations are applied to the plants at around the same time, diluted by a factor of 50 ml GROW A plus 50 ml GROW B/Trace Element Concentrate to 10 litres water.

EXAMPLE 3 TRACE ELEMENT CONCENTRATE: The following solution is designed for addition to either the BLOOM B or GROW B formulation. The Trace Element Concentrate is made up separately from the A and B solutions described in Examples 1 and 2, then added to each B solution (ie BLOOM B and GROW B) in the ratio of 1 volume to 9 volumes of B. The fully constituted B mix is filtered before packaging.

PART 1: The following amounts are dissolved in about 85 litres of water.

310 gm manganese sulphate monohydrate 220 gm zinc sulphate heptahydrate 40 gm copper sulphate pentahydrate PART 2: The following amounts are added to about 10 litres of water.

25 gm sodium molybdate dihydrate with stirring then, when fully dissolved, ADD 110 gm triethanolamine 230 gm boric acid then stir until fully dissolved 420 gm glycine and stir until fully dissolved.

FINAL MIXTURE Add all of PART 2 to PART 1, stir, then make up to 100 litres and stir again.

EXAMPLE 4 ONE-PART GROW FORMULATIONS: The following stock solutions comprise a combination of magnesium sulphate and calcium glycerophosphate/hypophosphite. The formulations differ only in the form of iron used (FeEDTA or FeEDDHA). Any other iron chelate of similar composition can be used.

COMPONENT 1st FORMULATION 2nd FORMULATION g/litre in stock (to be diluted 200 ml to 10L)

Magnesium sulphate 12.5 12.5 Calcium glycerophosphate 3.0 3.0 Calcium hypophosphite 3.6 3.6 Potassium nitrate 26 26 Calcium nitrate 24 24 Ammonium nitrate 5.8 5.8 Trace element mixture 0.7 0.7 (see Example 6) FeEDTA 0.33 FeEDDHA . ~ 0.7 The natural pH of the stock solution is close to neutral. The pH is lowered into the range 5 to 6 with the addition of nitric acid.

If desired, the GROW stock solutions can be doubled in strength.

EXAMPLE 5 ONE-PART BLOOM FORMULATIONS Both of the following stock solutions comprise a combination of magnesium sulphate and calcium glycerophosphate/hypophosphite. These formulations have FeEDTA or FeEDDHA as the iron source. However, any other iron chelate of similar composition can be used.

When preparing the formulations, the calcium glycerophosphate and the calcium hypophosphite should be fully dissolved before addition of at least some of the other components. Preferably, the trace elements are dissolved first, before adding any other components.

COMPONENT AMOUNT /litre in stock to be diluted 200 ml to 10L)

Magnesium sulphate Magnesium sulphate v .5 Calcium glycerophosphate 6.0 Calcium hypophosphite 11.4 Potassium nitrate 30 Calcium nitrate 10.4 Ammonium nitrate 1.7 Trace element mixture 0.7 (see Example 6) FeEDTA/ FeEDDHA 0.33/ 0.7 Potassium sulphate 6.0 There was a bit of precipitate in each stock solution, but this was easily resuspended before use.

The natural pH of the BLOOM stock solution is near neutral. The pH is lowered into the range 5 to 6 with the addition of nitric acid.

EXAMPLE 6 TRACE ELEMENT MIXTURE:

COMPONENT Amount (g) for 20 litres of stock Manganese sulphate 3.1 Zinc sulphate 2.2 Copper sulphate 0.4 Sodium molybdate 0.25 Boric acid 2.3 Triethanolamine 1.1 Glycine 4.2 Cetrimide 0.5 While the present invention has been described in terms of preferred embodiments in order to facilitate better understanding of the invention, it should be appreciated that various modifications can be made without departing from the scope of the invention, as defined in the following claims. Therefore, the invention should be understood to include all such modifications within its scope.

Claims (18)

THE CLAIMS:

1. A plant nutrient formulation comprising a synergistic mixture of: (i) an agriculturally acceptable surfactant, with either or both of the following components: (ii) an amine compound selected from secondary amines, tertiary amines and hydroxylated amines, (iii) a branched chain amino compound, together with other conventional plant nutrients and additives, as desired.

2. A plant nutrient formulation according to claim 1, comprising both an amine compound (ii) and a branched chain amino compound (iii).

3. A plant nutrient formulation according to claim 1 or claim 2, wherein the surfactant is a quaternary ammonium cationic detergent.

4. A plant nutrient formulation according to claim 3, wherein the surfactant is cetrimide.

5. A plant nutrient formulation according to any one of claims 1 to 4, comprising 50 to 150 mg/l of the surfactant.

6. A plant nutrient formulation according to any one of claims 1 to 5, wherein the amine compound (ii) is triethanolamine.

7. A plant nutrient formulation according to any one of claims 1 to 6, comprising 4.5 to 6.5 mg/l of the amine compound (ii).

8. A plant nutrient formulation according to any one of claims 1 to 7, wherein the branched chain amino compound (iii) is an amino acid.

9. A plant nutrient formulation according to claim 8, wherein the amino acid is glycine.

10. A plant nutrient formulation according to any one of claims 1 to 9, comprising 20 to 25 mg/l of the branched chain amino compound (iii).

11. A plant nutrient formulation comprising (i) magnesium sulphate and (ii) a calcium salt being calcium glycerophosphate, calcium hypophosphite or a combination thereof, together with other conventional nutrients and additives, as desired.

12. A plant nutrient formulation according to claim 11, comprising 200 to 300 mg/l of magnesium sulphate.

13. A plant nutrient formulation according to claim 11 or claim 12, comprising both calcium glycerophosphate and calcium hypophosphite.

14. A plant nutrient formulation according to any one of claims 11 to 13, comprising 50 to 400 mg/l of the calcium salt(s).

15. A plant nutrient formulation according to claim 13, comprising 125 to 350 mg/l of the calcium salts.

16. A plant nutrient formulation according to any one of claims 11 to 15, further comprising glycine.

17. A plant nutrient formulation according to any one of claims 1 to 16, being a hydroponics formulation.

18. A plant nutrient formulation substantially as described herein and with reference to any one of Examples 1 to 6.