The present invention relates to a process by which agricultural fertilisers intended for use in connection with sustainable farming can be manufactured via processes not dependent on the consumption of fossil fuels. The process of the present invention and the product obtained thereby provides significant advantages compared with processes and products of the prior art.

Brief description of the Background Art

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

Many crops are currently grown agriculturally for both human foods and animal fodder that are annuals requiring high levels of nutrification.

Fertilisers for such annual crops need to be high in nitrogen and are currently manufactured by chemical processes derived from the consumption of depleting fossil fuels such as natural gas and crude oil.

Such practices are inherently expensive and ultimately un-sustainable and global agriculture needs to move away from annuals to perennial crops which can be nutrified by fertilisers derived from non- depleting resources.

Such crops, which can be biennials or perennials are known for both human food and fodder production.

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

Conventional modern agricultural fertilisers have been based almost entirely on chemical entities which are rapid release water soluble nutrient sources. Such fertilisers are inherently inefficient as much nutrient intended for the crop is leached out by rain water and can pollute surface waters. Moreover, because of this rapid nutrient solubility such fertilisers only remain in the soil for one growing season, little or nothing of the nutrient input remains for future growing seasons. This means that large quantities of such fertilisers have to be applied at least annually. There is evidence to suggest that the repeated use of large quantities of rapidly soluble chemical fertilisers together with the frequent ploughing that is involved, impoverishes agricultural soil through structural degradation and erosion.

Furthermore, on a global scale, the application of large quantities of rapid solubility chemical fertilisers based on fossil fuels, cannot be sustained.

It is an object of the present invention to provide an improved process for producing agricultural fertilisers, suitable for biennial and perennial cultivation, that is retained in the soil for longer periods and manufactured from renewable raw material and energy sources

Summary Description of the Invention

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

(a) Batching and blending dry nutrient containing calcined powder to give dry powders comprising an intimate mixture of powders containing insoluble phosphatic and potassic nutrients;

(b) Absorbing liquidous nutrient containing proteinaceous slurries on to the dry powders;

(c) Allowing time for an exothermic reaction to thermally polymerise the proteinaceous slurries and absorb the cross-linked nitrogenous polymer onto the dry powders to produce a cake;

(d) Granulating the cake so as to complete the thermal polymerisation process to produce an insoluble nitrogenous material intimately mixed with insoluble phosphatic and potassic nutrients.

The batching of step (a) may comprise batching pyromorphic powders containing primary, secondary and tertiary agronomic nutrients, with the exception of nitrogen, derived from various non-fossil fuel consuming industries as co-products.

The blending of step (a) may comprise dry blending these calcined powders in ratios to provide appropriate agronomic nutrient levels of: phosphate, potash, calcium, magnesium, iron, sulphur and trace elements.

The process may include, preferably as part of step (b), wet blending the above dry blended powders with liquidous solutions, suspensions, slurries and or pastes containing organic nitrogen agronomic nutrients, such as proteinaceous residues, derived from various non-fossil-fuel consuming industries as co-products. The process may include absorbing the liquidous ingredients onto the dry powder entities to produce a cake.

The process may include granulating the cake so as to produce stable, storable, spreadable agglomerated agricultural extended release fertiliser.

Granulating the cake preferably provides a balanced fertiliser with release profiles of all primary, secondary and tertiary nutrients extending to three years.

Advantageous calcined powders may be derived from the power generation industry burning wood or bio fuels; the food processing industries disposing of bone and offal by incineration the cement manufacturing industry calcination of feldspatic clays using non-fossil fuel eg bio fuels; the serwage and agricultural waste industries incineration of wastes.

In step (a) these and other various fine dry powders are advantageously blended together to give balanced ratios of phosphate and potash.

During wet blending these balanced ratio powders may be blended with nitrogenous arising such as microbial digestates from the processing of human food waste, agricultural waste and or sewage wastes. Advantageously the resulting cake has a balanced ratio of nitrogen, phosphate and potash.

When absorbing the liquidous ingredients onto the dry powder, auxiliary phyto nutrients, pH adjusters and trace elements, all derived from waste produced without fossil fuel, may advantageously be added.

During wet blending the agglomeration of the crumbled cake may advantageously be achieved by simple rotary cascading to form granules, thus consuming a minimal amount of power.

Also, when granulating the cake the formation of granules is exothermic because of the slaking reaction of the liquidous portion on the components of the dry powder portion. Thereby no further thermal energy is needed to produce a dry, stable, storable and spreadable fertiliser granule.

The granular product produced exhibits balanced release of nitrogen, phosphate and potash plus calcium, magnesium, sulphur and iron and a full range of trace elements; over a period of up to three years in agricultural soil.

According to the present invention there may beprovided a process for the manufacture of extended release balanced nutrient granular fertiliser for the agricultural cultivation of biennial and perennial crops, wherein the crop is sustained without further nutrification for up to three years. The provision of such an extended release balanced fertiliser facilitates the cultivation of longer term crops than are currently conventionally grown. This in turn reduces the structural degradation caused by excessive fertilisation and frequent ploughing.

Moreover, the proposed manufacturing route to these extended release balanced fertilisers is not dependent on the consumption of depleting fossil fuels such as natural gas and or crude oil, and may thus be said to be sustainable.

Furthermore the total quantity of fertiliser needed for cropping is significantly reduced via both the avoidance of leaching and the selection of appropriate biennial and perennial crops.

Many conventional annual crops, such as cereals, require massive applications of chemical fertilisers in general and nitrogenous nutrients in particular. Much of this nutrification is lost through leaching, little of this nutrification survives in the upper levels of the soil to serve future crops.

Many conventional annual crops, such as cereals, can be replaced by biennial and or perennial crops, both for human food production and animal grazing and feeding.

Many such biennials and perennials require less nitrogenous nutrient than conventional annual crops, which is to say they benefit from a balance nitrogen, phosphate and potash fertiliser formula.

However, to be effective such balanced fertilisers must have extended nutrient release profiles, if biennials and or perennials are to be grown without the need for further nutrification.

Many perennial crops, such as legumes, contribute to soil fertility via the process of nitrogen fixation from the atmosphere, therefore a balanced fertiliser feed, without the need for excessive nitrogen, will suffice to grow such biennials and perennials.

Novel temperate botanical cultivars are being developed for growth as biennials and or perennials grown over a three year period that have the capability to displace many conventional annual crops for both human food production and food animal rearing.

However, the economic and sustainable cultivation of such longer term crops depends on the availability of appropriate balanced extended release fertilisers, derived via renewable energy and raw material based manufacturing routes.

What is needed, on a global scale, is a zero fossil fuel route to balanced nutrient extended release fertilisers. It is preferably a feature of the present invention that all the energy consumed and raw materials processed are renewable.

It is preferably a further feature of the present invention that nutrient losses caused by leaching of the soil is virtually eliminated. This is achieved because virtually all of the primary, secondary and tertiary nutrients are present in water insoluble forms.

Thus extended release nitrogen is preferably provided by proteinaceous residues derived from the human food, agriculture and sewage industries via processes such as microbial digestion.

The extended release phosphates are preferably provided by calcined phosphates derived from human and animal food industries, and or the sewage industry.

The extended release potash is preferably provided by calcined oxidics derived from wood and bio fuel burning powerstations and cement manufacturing operations using feldspahtic clays and bio fuels. Additionally all secondary nutrients, calcium, magnesium, sulphur and iron are similarly preferably provided and derived, as are a full range of trace elements.

The agronomic release mechanism by which nutrients are released and made available to crops over extended periods of time, from the product of the present invention, are preferably based mainly on soil- born microbial enzymic activities.

The overall agronomic effect according to the present invention is that biennial and perennial crop growth and ripening are maximised via the provision of balanced nutrification over a period of up to three years.

According to the present invention current non sustainable, expensive, inefficient and soil damaging agricultural chemical fertilisers applied annually, may be replaced by one single fertiliser application every third year, that provides balanced extended nutrification for the cultivation of biennial and perennial crops.

The specific agricultural and commercial objectives of the present invention will next be explained:

Biennial and perennial crops vary in their nutrificational requirements but in most cases have distinctly different fertiliser needs to conventional annual crops. An important agricultural and commercial objective of the present invention is to cater efficiently for the nutrificational requirements of longer life- cycle crops. Germination of biennial and or perennial crops may either take place via self seeding or seedlings propagated elsewhere may be transplanted. Co-cropping of up-standing biennial varieties above perennial ground cover may be an appropriate system.

Once biennial and perennial crops are established they grow at a relatively consistent rate compared to annual crops which show a spring growth surge. Such biennial and perennial crops therefore need continuous nutrient provision throughout their life cycle, rather than for example high nitrogen spring applications. Throughout their growing stages biennial and perennial crops need provision of nitrogen, phosphate and potash in a balanced ratio. The nitrogen provides for leaf and stem growth, the phosphate encourages root growth and the potash induces the ripening of the crop.

It is a feature of the present invention that the product envisaged provides extended balanced nutrification for up to three years. It should be noted that different species of biennals and perennials require variants for the above theme, and it is a preferred feature of the present invention that these can be provided in the form of crop specific fertiliser formulations.

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 growth. This interlinkage has been studied because it provides for extended nutrient release, of otherwise insoluble nutrients, over significant periods of time.

There is now sufficient experimental evidence that suggests that a link exists, in nature, 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 crop growth is low, so is soil-born microbial activity.

It is also known that soil-born microbial activity is ground temperature dependent. In perennial agricultural situations this effect is important as the seasons change. It appears to be a natural phenomenon that when soil temperatures drop, in autumn and through winter, microbial activity diminishes. Through our studies of this phenonemen we have been able to explain the longevity of nutrient release from the product of the present invention.

The interlinkage between the mechanisms of microbial population growth and perennial agricultural crop growth is believed to be the mode by which microbes contribute to the feeding of crops. 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 then available for absorption by 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 still further nutrients are made available in the soil. These excess nutrients are taken up by the crops and the crops grow accordingly.

Because the nutrient release mechanism is temperature dependent it follows that less of the extended release nutrient, that is the subject of the present invention, is solubilised in autumn and winter. This conserves nutrient in the ground, in insoluble form, which, is then available to the microbes and the crop in the following spring.

Overall, the effect created is that our extended release fertilisers over-winter in the soil and are not leached out by winter rains.

Via this microbially linked mechanism we have now demonstrated that our extended release fertilisers can provide crop nutrients for up to thirty six months in the ground.

The significance of this theory and practical demonstration of what may be called "Phyto-Microbial Nutrification", to the present invention, is that the provision of extended release nutrients becomes possible for the cultivation of biennial and perennial crops, wherein the plants are nutrified during their complete life cycle from seedlings to fully ripe crop.

The provision of extended release nutrification is achieved in the present invention through the incorporation of sources of nutrient that are in themselves insoluble but are solubilised over time by microbial activity.

Additionally, some fast active sources, that is soluble sources, of nutrients may also be incorporated in the extended release fertiliser to aid initial crop growth, for species where this is appropriate.

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

Basically, our proposed approach is to manufacture agricultural fertiliser wherein a proportion of the primary, secondary and tertiary nutrients are present in water insoluble forms. This is to state that a proportion of the primary nutrients, nitrogen, phosphate and potash together with a proportion of the secondary nutrients, calcium, magnesium, sulphur and iron and a proportion of the trace element tertiary nutrients are all in a physico-chemical form which does not dissolve in rain water. These insoluble forms of nutrient only dissolve, and become available to the crop, via soil-born microbial activity over a period of many months, up to three years.

The fertiliser compositions, according to the present invention, can contain phyto nutrients in conventional rapid release form, but, these are augmented by extended release variants of these nutrients.

The physico-chemical approach used, in the present invention, is to provide water insoluble nutrients which have either been polymerised or pyrolysed.

Water insoluble nitrogen is preferably provided in cross-linked proteinaceous format. This is achieved via thermal polymerisation of the oligomeric protein residues in the food industry microbial digestate. The thermal polymerisation may be induced by the exothermic slaking reaction during the granulation stage.

Water insoluble phosphates may be provided in calcined oxide format. This is achieved via pyrolysis of hydroxides and hydrated entities in the industrial co-products of the food waste processing industry. This pyrolysis takes place when these phosphatic raw materials are kilned.

Water insoluble potasssics are preferably provided in calcined combined oxidic structures. This is achieved via pyrolysis of potassic mineral entities in the industrial co-products of the power generation and cement manufacturing industries. This pyrolysis takes place when these potassic raw materials are kilned.

Similar kiln pyrolysis also provides secondary and trace elements in water insoluble format. Thus water insoluble sources of calcium, magnesium, sulphur and iron are provided.

According to the present invention the above polymerised and or pyrolysed raw materials contribute to the analysis of the proposed extend release fertiliser and specifically provide the longevity of the nutrient profiles.

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

1 ) Concentrated nitrogen containing digestates derived from human, agricultural or sewage waste microbial treatments.

2) Pyro-morphic phosphatic powders derived from the human food industry or sewage waste incineration processes. 3) Pyro-morphic potassic powders derived from the power generation and or cement manufacturing furnacing or kilning processes.

4) Secondary and tertiary pyro-morphic powders from various industrial processes.

5) 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:

1 ) Concentrated nitrogen containing digestates provide nitrogen in extended release format and act as a micro-fibrous organic granulation binder.

2) Pyro-morphic phosphatic powders provide phosphate in extended release format and act as a slaking granulation builder.

3) Pyro-morphic potassic powders provide potash in extended release format and act as both an exothermic agent and a slaking granulation builder.

4) Secondary and tertiary powders provide the corresponding element in extended release format and act as absorbing granulation builders.

5) Auxiliary phyto-nutrients provide analysis boosting and some rapid release nutrients and contribute to granulation binding.

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

1 ) Concentrated nitrogen containing digestate 10% to 60% by weight.

2) Pyro-morphic phosphatic powder 10% to 40% by weight.

3) Pyro-morphic potassic powder 10% to 40% by weight.

4) Secondary and tertiary pyro-morphic powder 1 % to 20% by weight.

5) Auxiliary phyto-nutrients 1 % to 40% by weight.

From the above ranges it is advantageous to select raw material blends for granulation that contain approximately 50% liquidous components and 50% powdered components. Depending on the nitrogen: phosphate: potash ratio required, and the release characteristics, various recipes can be used within the above range.

A typical balanced formula fo r agricultural application to perennial crops such as speciality monocotyledens, with a 5:5:5 nitrogen to phosphate to potash ratio and a nutrient profile extending to 36 months, may be produced from the following exemplifying recipe of raw materials for granulation:

1 ) Concentrated nitrogen containing digeste; 50 parts by weight containing 100 Kg per tonne of nitrogen.

2) Pyro-morphic phosphatic powder; 20 parts by weight containing 180 Kg per tonne of P ₂ 0 ₅ .

3) Pyro-morphic potassic powder; 20 parts by weight containing 180 Kg per tonne of K^O. Secondary and tertiary pyro-morphic powders 1 part by weight.

4) Auxiliary phyto-nutrient 19 parts by weight of conventional urea plus mineral phosphatic and potassic fertilisers in solubilised format.

The 1 10 part by weight of the above charge is reduced by water loss during granulation to 100 parts of finished product.

It should be noted that the above is only an example of the analyses that can be achieved via the present invention. Our work is continuing and balanced formulations as high as 8:8:8 are possible. Also, it should be noted that weighted formulations such as 10:7:7 and 7: 10:7 and 7:7: 10 are also possible. However, it is not intended nor is it currently possible or desirable in the present invention, to produce high nitrogen formulations.

The granulation process via which the sustainable agricultural fertiliser of the present invention is to be manufactured will now be delineated by way of example:

This granulation process may be described as a thermo-chemical granulation process. The

process comprises six steps: a) Batching of pyromorphic powder to provide the desired nutrients except nitrogen. b) Dry blending these calcined powders in ratios to provide the desired ratio of nutrients except nitrogen. c) Wet blending the above dry powders with concentrated nitrogenous proteinaceous digestate in the required ratio to provide the nitrogen requirement. d) Allowing time for the adsorption of the liquidous component onto the dry powder component and for the onset of the slaking reaction. e) Granulating the resulting setting cake so as to exothermically set the agglomerates. f) Sizing the resulting granules when set, via sieving to produce the desired agglomerate size range.

The exothermic reaction is the principle advantage of this form of thermo-chemical granulation. The exothermicity is generated by the water in the liquidous digestate raw material slaking the dry alkaline earth raw materials in the pyromorphs.

This exothermicity also cross-links the proteinaceous oligomers and amino acids present in the concentrated nitrogenous digestate raw material, thus presenting the nitrogen contained in water insoluble extended release format.

It should be noted that no expensive chemical catalyst needs to be added to induce this relatively simple thermal cross-linking process.

Overall approximately 10% of the water contained in the liquidous raw materials is lost during the granulation slaking and autogenous drying, that is to say curing, process. Further water is chemically absorbed.

The finished product, that is the improved agricultural fertiliser for sustainable farming, provided by the present patent, may be described as follows:

The finished product is an extended release balanced formula organo-mineral fertiliser derived from raw materials and processes that are essentially fossil fuel free, that provides nutrification for up to 36 months, thus allowing for the cultivation of perennial crops.

The physical form of the finished product is a dry storable and easily applied granular fertiliser. Granulometry can be controlled to yield 0.5mm to 1.5mm and or 1.5mm to 2.5 and or 2.5mm to 4mm spheroids, which are appropriate for application via various conventional agricultural material spreading devices. The primary nutrient content of the finished product can range from low levels of nitrogen, phosphate and potash to formulations as high as 8:8:8 that is 80 Kg per tonne nitrogen; 80 Kg per tonne phosphate; 80 Kg per tonne potash.

Fertilisers with a balanced or close to balanced nitrogen phosphate to potash ratio are the primary aim of the present invention.

It is our intention that all these primary nutrients remain available in a balanced composition throughput the release profile of the product.

The release profile of the product can extend to up to 36 months from application.

It is not within the scope of the present invention to produce high nitrogen fertilisers. It is not our intention to provide high nitrogen fertilisers for sustainable farming.

The finished product may be bio-chemically defined as containing cross-linked insolubilised proteinaceous nitrogen and calcined mineral phosphatic and potassic derivatives. These specific sources of nutrients provide the product in extended release format. Release of nutrients thus provided is via soli-born microbial enzymic activity not rain water solubility.

However, some conventional fertiliser raw materials may also be contained in the finished product to provide for some rapid release of nutrients to stimulate early crop growth.

All of the principle raw material used according to the current invention can be derived from fossil fuel free processes.

The finished product according to the present invention provides for the economic sustainable nutrification of land on which biennial and perennial crops are to be grown.

Additionally, the finished product of the present invention provides for agricultural nutrification regimes that are achieved ergonomically via one dressing every third year rather than multiple applications of rapidly leached conventional fertilisers.

Such extended release agricultural fertilisers as provided by the current invention are agronomically preferable, that is they cause less damage to soil structure, than conventional chemical fertilisers.

Taken together the above advantage constitute a significant improvement in nutrification, that can lead to sustainable farming on a global basis. According to a second aspect of the present invention there is provided a finished product derived from the process of the first aspect. The finished product may be an agricultural nutrient composition.

According to a third aspect of the present invention there is provided an agricultural nutrient, comprising a granulated blend of polymerised (ie cross-linked) organic waste plus calcined phosphatic and potassic kilned residues.

The composition preferably has nutrient profiles extending to 36 months.

Preferably at least part of the polymerised organic waste and calcined phosphatic and potassic kilned residues are aqueously solubilised by soil-born microbial enzymic activity.

According to a fourth aspect of the present invention there is provided an agricultural nutrient composition, comprising a granulated blend of polymerised organic nitrogen containing wastes together with calcined mineral sources of phosphate, potash, secondary phyto nutrients and phyto trace element.

According to a fifth aspect of the present invention there is provided an agricultural nutrient composition obtainable by the process of the first aspect.

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