GB2498981A

GB2498981A - Improved horticultural nutrient compositions

Info

Publication number: GB2498981A
Application number: GB1201756.2A
Authority: GB
Inventors: John William Carson
Original assignee: SYNCHEMICALS Ltd
Current assignee: SYNCHEMICALS Ltd
Priority date: 2012-02-01
Filing date: 2012-02-01
Publication date: 2013-08-07
Also published as: GB201201756D0

Abstract

A process for the manufacture of a horticultural nutrient composition comprises: blending de-polymerised nitrogenous and phosphatic monomers and/or oligomers and/or finely ground polymers together to give a blended feed; reacting this blended feed with an acid catalyst to give a reacting feed; absorbing the reacting feed onto dry powder(s) to produce a cake; and granulating the cake to produce a mixed polymeric substance. Preferably the acid catalyst is phosphoric acid, sulphuric acid and/or nitric acid(s). Also preferably the dry powder(s) are based on minerals and/or oxides containing potassium, calcium, magnesium, sulphur and phyto nutrient trace elements. The polymerisation process takes place during granulation, preferably at temperatures between 80 and 120Â°C. In another embodiment a horticultural nutrient composition comprises a granulated blend of re-polymerised organic waste, wherein the organic waste comprises de-polymerised nitrogenous and phosphatic monomers and/or oligomers and/or finely ground polymers. Preferably the polymeric substance has controlled sequentially attenuating nutrient release properties.

Description

1

IMPROVED HORTICULTURAL FERTILISERS

Introduction

5 The present invention relates to a process by which horticultural fertilisers can be manufactured in controlled sequential attenuating form. The process of the present invention and the product obtained thereby provides significant advantages compared with processes and products of the prior art.

10 Brief Description of the Background Art

Current practice using conventional nutrificational approaches in horticulture will first be described:

15 Many crops are grown horticulturally that have extended growing periods, or are biennials or perennials. While such subjects as florals, decoratives, hardy nursery stock and arborials are high value crops their nurturing involves ergonomically intensive high cost nutrification systems.

20 Current horticultural practice, in connection with the above crops may involve a base fertiliser plus frequent application of liquid fertiliser. Such practice is inherently costly and agronomically inefficient as considerable quantities of nutrients and lost through leaching.

The known prior art of fertiliser nutrient provision, relevant to the present invention, will next be 25 reviewed:

Conventional modern agricultural fertilisers have been based almost entirely on rapid release water soluble nutrients.

30 In horticultural similar rapid release water soluble nutrients are extensively used in the form of liquid feeds. However, there is prior art concerning slower release base fertilisers in horticulture.

Entities such as dried blood, hoof and horn and bone meal are provided in the forms of 35 powders, blends and agglomerated products as slow release nitrogen and phosphate sources for horticultural use.

Additionally, recently, various organic waste digestates containing partially decomposed excreta and or waste human or animal foods plus agricultural wastes have been processed for

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use as slow release nitrogen and phosphate sources, for both horticultural and agricultural use.

While these various waste and co-product based fertilisers have a role to play in some sectors 5 of horticulture their effect is limited and the growth results obtained can be un-predictable.

It is an object of the invention to provide an improved process for producing a horticultural nutrient composition.

10 Another object is to provide a process for producing an improved horticultural nutrient composition, especially one providing for controlled nutrient release from organic materials, particularly organic materials that have been further processed so as to provide re-polymermised consistent release entities.

15 Summary and Detailed Description of the Invention

According to a first aspect of the present invention there is provided a process for the manufacture of a horticultural nutrient composition, the process comprising:

20 (a) Blending de-polymerised nitrogenous and phosphatic monomers and/or oligimers and/or finely ground nitrogenous and phosphatic polymers together to give a blended feed;

(b) Reacting this blended feed with an acid catalyst to give a reacting feed;

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(c) Absorbing the reacting feed onto dry powder(s) to produce a cake;

(d) Granulating the cake to produce a mixed polymeric substance.

30 Step (d) preferably provides a mixed polymeric substance with controlled sequentially attenuating nutrient release properties.

In step (d) the nitrogenous and phosphatic monomer and/or oligomers when present may be polymerised; and the finely ground nitrogenous and phosphatic polymers when present may 35 be incorporated into a larger polymeric substance.

In Step (a) the nitrogenous and phosphatic de-polymersied raw material is preferably based on co-product derived from the human food, agricultural and/or sewage industries.

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In Step (b) the acid catalyst is preferably phosphoric, sulphuric and, and/or nitric acid(s).

In Step (c) the dry powder(s) are preferably based on minerals and/or oxides containing potassium, calcium, magnesium, sulphur and phyto nutrient trace elements.

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Auxiliary phyto nutrients may also be added to the reaction mixture.

The polymerisation reaction preferably takes place during granulation at temperatures between 80 and 120°C.

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The granulation is preferably carried out in a pan or dish or disc granulator.

The granules formed are preferably thermally cured by the process or are subsequently thermally cured.

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The granular product produced preferably exhibits extended phyto-nutrient release in changing ratios with time, in horticultural growing mediums such as soils and composts.

According to the present invention there is provided a process for the manufacture of 20 controlled sequentially attenuating granular horticultural fertiliser. In this context, by controlled sequentially attenuating, we mean that the fertiliser releases ratios of primary nutrients, that is nitrogen, phosphate and potash, which vary over time. Thus the initial release ratio may be 2 parts of nitrogen to 1 part of phosphate to 0 part of potash. Three months later the release ratio may be 1 part of nitrogen to 1 part of phosphate and 1 part of potash. Six months later the 25 release rate may be 1 part nitrogen to 1 part phosphate to 2 parts potash.

The provision of such controlled sequentially attenuating compound granular fertilisers provides for a novel and effective form of horticultural nutrification wherein plant growth and ripening is optimised by retention of nutrients and provision of those nutrients in appropriate 30 ratios throughout the crop growth cycle.

The process for the manufacture of horticultural fertiliser according to the present invention involves the polymerisation of nitrogenous and phosphatic materials.

35 The horticultural fertiliser product according to the process invention is a compounded and granulated blend of water soluble and water insoluble nitrogen and phosphate sources together with slowly water soluble potash sources.

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It is a feature of the present invention that the processing step of granulation is aided by nitrogen and phosphate compound formation which takes the form of a thermal polymerisation reaction. This is to say that the formation of essentially water insoluble nitrogenous and phosphatic polymers contributes to the granule binding action. Moreover the exothermicity 5 generated by the polymerisation contributes to the granule setting and drying reactions.

The agronomic release mechanisms by which nutrients are released and made available to crops from the product of the present invention are combinations of water solubilisation and soil-born microbial enzymic activity.

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As a result of this duplex agronomic release mechanism nitrogen, phosphate and potash nutrients become available to the crop at varying rates and in varying ratios which mirror growth requirements through the plant growing cycle.

15 The overall agronomic effect according to the present invention is that crop growth and ripening are maximised whereas the ergonomics involved in horticultural nutrification are minimised and losses of nutrient through leaching are also minimised.

20 According to the present invention current expensive and agronomically inefficient horticultural nutrification practice may be replaced by one single fertiliser application, at the beginning of cultivation, that provides for the charging nutrient ratios required by the crop throughout its growing cycle, or until point of sale.

25 The specific horticultural, agronomic and commercial objectives of the present invention will next be explained:

Horticultural crops vary in their nutrient requirements but the following basic sequence may be regarded as average.

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After germination, which is usually carried out in a growing medium devoid of nutrients, the young plants firstly require appreciable nitrogen and some phosphate for early growth. Therefore soluble nitrogen and phosphate need to be provided rapidly from the fertiliser of the present invention.

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During mid life the crop requires nitrogen and phosphate to maintain growth and develop the root system plus some potash. Therefore slower release nitrogen, phosphate and potash need to be provided over a period of several months.

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As the end of the crop growing sequence approaches the plants need further nitrogen and phosphate plus significant potash to secure ripening. Therefore some extended release nitrogen and phosphate and significant potash needs to be provided over many months.

5 If the above sequence of changing ratio nutrients can be provided then, agronomically the crop is best served and economically the crop yield is maximised.

It should be noted that different species of plants require variants on the above theme, and it is a feature of the present invention that these can be provided in the form of crop-specific 10 fertilisers.

The basic agronomic concept behind the present invention will next be presented:

Our theoretical research has focused on a concept that links soil microbial activity with crop 15 growth. This interlinkage has been studied because it provides for slow, extended and attenuated nutrient release over and above that provided in the short term by aqueous leaching.

There is now sufficient experimental evidence that suggests that a link exists, in nature, 20 between crop growth and soil-born microbial activity. This is to state that, when soil-born microbial activity is high this is mirrored by high crop growth rates. Conversely, when soil-born microbial activity is low, so is crop growth.

It is also known that soil-born microbial activity is ground temperature dependent. In 25 agricultural situations this effect is important as the seasons change. However, in horticultural situations systems are applied to protect the crop from temperature extremes. Thus in the case of the present invention, which relates to horticultural ie protected crops, the temperature dependence of microbial activity may be said to be of less importance than in agriculture.

30 At a relatively constant soil temperature the control over microbial activity is the provision over time of microbial nutrients, that is nutrients that are taken-in by soil-born microbes.

If, in addition to quickly available, that is to say water soluble nutrients, there is provided slow and extended release sources of microbial nutrients then their soil-born populations continue 35 to increase.

Steadily increasing populations of soil-born microbes, throughout the growing cycle of horticultural crops has an important bearing on the health of the crop, growth rates and ultimate ripening.

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The interlinkage in the mechanisms of microbial population growth and horticultural crop growth is believed to be the mode by which microbes contribute to the feeding of crops.

5 Firstly, the basis of the process by which microbes obtain their nutrients will be described:

The mechanism via which microbes feed is enzymic dissolution of nutrients. This is to state that soil-born microbes exude enzymic catalytic entities into the soil and that these catalysts solubilise nutrients such as nitrogen, phosphate and potash. These solubilised nutrients are 10 then available to the microbes.

The on-going effect of this solubilisation process on crops will now be described:

Because of the highly efficient catalytic solubilisation brought about by the microbial enzymes 15 still further nutrients are made available in the soil. These excess nutrients are taken up by the crops and the crops grow accordingly.

Thus, we believe, microbes and crops benefit together in a symbiotic relationship in terms of the provision of solubilise nutrients.

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The significance of this theory, which may be called "Photo-microbial Nutrification", to the present invention is that the provision of slow and extended release nutrient sources to the soil is vital if microbial activity is to be sustained and increased during the complete life cycle of horticultural crops.

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The provision of slow and extended release nutrients is achieved in the present invention through the incorporation, in addition to fast acting soluble sources, of further sources of nutrients that are in themselves insoluble but are solubilised over time by microbial activity.

30 The balance between fast acting water soluble sources and slower acting microbially solubilised sources provides the key to horticultural fertilisers that present a time-varying ratio of nutrients to crops.

The basic physico-chemical approach of the present invention will next be outlined:

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Basically, our proposed approach is to manufacture advanced horticultural fertilisers wherein a proportion of the primary nutrients are present in water insoluble forms. This is to state that a proportion of the nitrogen, phosphate and potash is in physico-chemical forms which do not

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dissolve in rain or irrigation water but which are slowly liberated by the activity of soil-born microbes.

The fertiliser compositions, according to the present invention, can contain all the normal 5 relatively rapid release primary, secondary and tertiary phyto-nutrients, but these are augmented by controlled sequentially attenuating release water insoluble entities.

The physico-chemical approach used, in the present invention, to provide water-insoluble nitrogenous and phosphatic nutrients involves the re-polymerisation of previously partially de-10 polymerised organic materials, plus the provision of finely ground polymeric materials.

The provision of slow release potassic, plus secondary and tertiary nutrients for horticultural fertilisers is also provided for in the present invention. This is achieved through the incorporation of dry oxidic and mineral derivatives which are similarly leached over time by 15 microbial enzymic exudates.

Partially de-polymerised proteinaceous materials containing peptidic oligomers plus amino acids, and, bone based phosphatics are available from the human food industry and other organic material processing industries.

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Such co-products arise as digestates, which is to state that these materials have been de-polymerised so as to recover useful feed by-products. Processes such as aerobic, anoxic and anaerobic digestion are currently applied that produce pasteurised mixtures of protein and bone derived partially de-polymerised organic materials. These digestates are then 25 concentrated by processes such as thermal evaporation or reverse osmosis. The resulting concentrated de-polymerised organic liquors are used in various sectors of the animal feed industry.

These concentrated de-polymerised organic liquors from the above and other by-product 30 recovery processes provide the de-polymerised starting point for the manufacture of re-polymerised controlled sequentially attenuating release nutrients according to the present invention.

The above concentrates together with other nutrient ingredients are to be re-polymerised via 35 an acid catalysed reaction.

The basic polymer chemical approach to the present invention will next be defined:

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Through our research into further treatment of concentrated de-polymerised organic liquors we have now discovered that these may be re-polymerised by a catalysed acidic thermo-chemical process.

5 In terms of polymer chemistry what is involved is the formulation of a range of nitrogen linkages between amino acids and amino groups and other groups on oligomeric peptide chains so as to form polymer which in part resembles synthetic protein, urea formaldehyde and plastics such as nylon. These re-formed polymeric substances also take in phosphatic entities to their polymeric structures during the re-polymerisation reaction of the present invention.

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Because of the multifarious nature of the by-product raw materials used, namely the concentrated de-polymerised organic liquors, the resulting polymer is not a simple pure polymeric entity but a complex polymeric mixture.

15 The re-polymerisation process may be carried out in alkaline neutral or acidic conditions. Our currently preferred approach is acidic conditions wherein the acid may act as a polymerisation catalyst.

Our research is continuing into the nature and potential extent of the above re-polymerisation 20 reaction. This appears to be temperature dependent. Currently our preferred temperature range is 80°C to 120°C.

According to the present invention an acid is added to the concentrated de-polymerised organic liquor and this, at elevated temperatures brings about the re-polymerisation of 25 nitrogenous and phosphatic entities.

Several different acids, or blends of acids, or acid precursors may be used in the above re-polymerisation reaction.

30 Advantageous acids include sulphuric acid, nitric acid and phosphoric acid.

It will be recognised that these three acids contribute primary and or secondary nutrient to the finished fertiliser product.

35 The basic re-polymerisation process may now be defined:

According to the present invention concentrated de-polymerised organic liquors containing nitrogen and phosphate are further treated via a pH controlled catalysed re-polymerisation reaction at elevated temperatures.

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The result is a mixed polymer containing, controlled sequentially attenuated release nitrogenous and phosphatic nutrients of specific use in advanced horticultural fertilisers. Depending on the reaction temperature the resulting mixed polymer may either be slowly 5 soluble in water or insoluble in water but enzymically soluble in soil-born waters.

Our research has defined a simple manufacturing process for the production of granular horticultural fertilisers wherein the above catalysed thermal re-polymerisation process is achieved in and contributes to the fertiliser granulation process.

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The raw materials to be used in the above granulation process will now be described:

The raw material mix used in the present invention may be comprised of the following ingredients:

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1. Concentrated de-polymerised organic liquors derived from the human food processing industry, agriculture or sewage industries.

2. Acidic liquors such as sulphuric, nitric or phosphoric acids or blends or precursors 20 thereof.

3. Pyromorphic powders, that is powders of oxidic and or mineral nature that have been pyrolysed in connection with other industrial activities, and are thus dry and un-hyd rated.

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4. Auxiliary phyto nutrients conventionally used to provide agronomic sources of primary secondary or tertiary nutrients.

The principle roles of the above raw materials are as follows:

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1.The concentrated de-polymersied organic liquors provide labile nitrogen and phosphate sources.

2. Acidic liquors provides the acid catalytic reagent for the re-polymerisation reaction, and 35 may also provide agronomic nutrients.

3. Pyromorphic powders provide for fluidic adsorption during the re-polymerisation reaction and aid granulation and may additionally provide agronomic nutrients, notably potash.

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4. Auxiliary phyto nutrients provide additional primary secondary and tertiary nutrients with varying release properties ranging from rapid water solubility to more extended release patterns.

5 A range of recipes for the mix of the above raw materials will next be defined:

1. Concentrated de-polymerised organic liquor 10% to 40% weight.

2. Acid liquor 10% to 40% weight.

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3. Pyromorphic powder 10% to 40% by weight.

4. Auxiliary phyto nutrient 10% to 40% by weight.

15 From the above ranges it can be deduced that the raw material blend for granulation should contain approximately 50% liquidous components and 50% solid components.

Depending on the NPK ratio and analysis required, and the release characteristics, various recipes can be used within the above ranges.

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A typical recipe as widely used in horticulture, with a 14:7:7 nitrogen/phosphate/potash ratio and a nutrient provision span of 9 months may be produced from the following specific recipe of raw materials for granulation:

25 1. Concentrated de-polymerised organic liquor; 40 parts by weight containing 10% nitrogen and 5% phosphate.

2. Acid liquor 10 parts by weight containing 25% phosphate.

30 3. Pyromorphic powder; 30 parts by weight containing 18% potash.

4. Auxiliary phyto nutrients; 20 parts by weight containing 26% nitrogen 5% phosphate and 8% potash.

35 The granulation process via which the improved horticultural fertiliser described in the present invention is to be manufactured will now be delineated.

This granulation process may be described as a thermo-chemical granulation process. The process comprises six steps:

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1. Intimate mixing of the liquidous and powder raw materials to produce a moist cake.

2. Comminution of this moist cake through an appropriate sized sieve.

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3. Pan, dish or disc granulation of the comminuted cake.

4. Dry powder coating of the moist granules.

10 5. Sieving of the dry powder coated granules, with recycle of the over and undersized fractions.

6. Auxiliary drying of the on-size granules.

15 It should be noted that the final step (6) is auxiliary to the overall process. This is because the liquidous and dry powder raw material components react together exothermically during the main steps of the process (steps 1, 2, 3, 4 and 5). Temperatures between 80°C and 120°C may be produced via this exothermic reaction and extensive drying takes place.

20 This exothermic reaction is the principle advantage of this form of thermo-chemical granulation. The exothermicity is generated by the acid catalysed re-polymerisation reaction and by a slaking action of the excess acid with basic raw material components in the pyromorphic powders used eg the slaking of calcium oxide.

25 The exothermicity generated together with the chemical and physical adsorption of water by the pyromorphic powders brings about the setting, that is curing of the granules.

The curing granules may either be stacked in shallow layers, in which this drying process is completed via the slaking reactions plus evaporation, or, auxiliary thermal drying may be 30 carried out in a suitable dryer.

Overall approximately 20% by weight of water is lost during the drying of the finished product granular fertiliser. Further water is chemically absorbed.

35 The finished product of the process, according to the present invention will now be defined:

The finished product, that is the improved horticultural fertiliser provided by the present invention, may be described as follows:

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The finished product is a controlled sequentially attenuating provider of agronomic nutrients over an extended period of many months.

The physical form of the finished product is a dry storable and easily applyable granular 5 fertiliser. Granulatometry can be controlled to yield 0.5 to 1.5mm and or 1.5 to 2.5 and or 2.0 to 4mm spheroids, which are appropriate for usage in various sectors of horticulture.

The primary nutrient content of the finished product can range from low levels of nitrogen, phosphate and potash to formulations as high as 16% N; 8% P2O5; 8% K20.

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The release profiles of the finished product can be made to commence as 2:1:1 nitrogen, phosphate and potash; progress to a ratio of 1:1:1 in a matter of a month or as long as six months; then progress to 1:1:2 ratio in a matter of two months or as long as 18 months.

15 The finished product may be bio-chemically defined as containing re-polymerised synthetic protein-like water insoluble organic entities which slowly release nutrient via soil-born microbial enzymic activity. Also contained in the finished product are soluble phyto-nutrients and extended release potash and secondary and tertiary elements derived from the pyromorphic and mineral powders and auxiliary nutrients used.

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The finished product according to the present invention provides for the economic, ergonomic and environmentally superior nutrification of horticultural crops.

Specifically, the finished product of the present invention provides for horticultural nutrification 25 regimes that are achieved via one base dressing application rather than multiple applications of rapidly leaching conventional fertilisers.

Taken together the above advantages constitute a significant techno-commercial improvement in the manufacture of horticultural fertilisers.

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According to a second aspect of the present invention there is provided a finished product as described in relation to the first aspect. The finished product may be a horticultural nutrient composition.

35 According to a third aspect of the present invention there is provided a horticultural nutrient composition, comprising a granulated blend of re-polymerised organic waste, wherein the organic waste comprises de-polymerised nitrogenous and phosphatic monomers and/or oligimers and/or finely ground nitrogenous and phosphatic polymers.

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The composition preferably has controlled sequentially attenuating nutrient release properties.

Preferably at least part of the re-polymerised organic waste is aqueous-solubilised by soil-born microbial enzymic activity.

Preferably the granular product exhibits extended phyto-nutrient release in changing ratios with time, in horticultural growing mediums such as soils and composts.

Preferred features of any aspect are also preferred features of any other aspect.

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Claims

1. A process for the manufacture of a horticultural nutrient composition, the process 5 comprising:

(a) Blending de-polymerised nitrogenous and phosphatic monomers and/or oligimers and/or finely ground nitrogenous and phosphatic polymers together to give a blended feed;

10

(b) Reacting this blended feed with an acid catalyst to give a reacting feed;

(c) Absorbing the reacting feed onto dry powder(s) to produce a cake; 15 (d) Granulating the cake to produce a mixed polymeric substance.

2. The process according to Claim 1 where step (d) provides a mixed polymeric substance with controlled sequentially attenuating nutrient release properties.

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3. The process according to any preceding claim where in Step (a) the nitrogenous and phosphatic de-polymersied raw material is based on co-product derived from the human food, agricultural and/or sewage industries.

4. The process according to any preceding claim where in Step (b) the acid catalyst is 25 phosphoric, sulphuric and, and/or nitric acid(s).

5. The process according to any preceding claim where in Step (c) the dry powder(s) are based on minerals and/or oxides containing potassium, calcium, magnesium, sulphur and phyto nutrient trace elements.

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6. The process according to any preceding claim wherein auxiliary phyto nutrients are also added to the reaction mixture.

7. The process according to any preceding claim wherein the polymerisation reaction takes 35 place during granulation at temperatures between 80 and 120°C.

8.

The process according to any preceding claim wherein the granulation is carried out in a pan or dish or disc granulator.

15

9. The process according to any preceding claim in which the granules formed are thermally cured by the process or are subsequently thermally cured.

10. The process according to any preceding claim where in the granular product produced 5 exhibits extended phyto-nutrient release in changing ratios with time, in horticultural growing mediums such as soils and composts.

11. A horticultural nutrient composition, comprising a granulated blend of re-polymerised organic waste, wherein the organic waste comprises de-polymerised nitrogenous and

10 phosphatic monomers and/or oligimers and/or finely ground nitrogenous and phosphatic polymers.

12. The horticultural nutrient composition according to claim 11, wherein the composition has controlled sequentially attenuating nutrient release properties.

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13. The horticultural nutrient composition according to claims 11 or 12, wherein at least part of the re-polymerised organic waste is aqueous-solubilised by soil-born microbial enzymic activity.

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14. The horticultural nutrient composition according to any preceding claim wherein the granular product exhibits extended phyto-nutrient release in changing ratios with time, in horticultural growing mediums such as soils and composts.

15. A process as substantially hereinbefore described with reference to the Examples.

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16. A horticultural nutrient composition as substantially hereinbefore described with reference to the Examples.