WO2003059845A1 - Acidic potassium nitrate for irrigation fertilization of plants - Google Patents
Acidic potassium nitrate for irrigation fertilization of plants Download PDFInfo
- Publication number
- WO2003059845A1 WO2003059845A1 PCT/FI2003/000026 FI0300026W WO03059845A1 WO 2003059845 A1 WO2003059845 A1 WO 2003059845A1 FI 0300026 W FI0300026 W FI 0300026W WO 03059845 A1 WO03059845 A1 WO 03059845A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- potassium nitrate
- aqueous solution
- irrigation
- plants
- urea phosphate
- Prior art date
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- FGIUAXJPYTZDNR-UHFFFAOYSA-N potassium nitrate Chemical compound [K+].[O-][N+]([O-])=O FGIUAXJPYTZDNR-UHFFFAOYSA-N 0.000 title claims abstract description 127
- 235000010333 potassium nitrate Nutrition 0.000 title claims abstract description 65
- 239000004323 potassium nitrate Substances 0.000 title claims abstract description 61
- 238000003973 irrigation Methods 0.000 title claims abstract description 35
- 230000002262 irrigation Effects 0.000 title claims abstract description 35
- 230000002378 acidificating effect Effects 0.000 title claims abstract description 28
- 230000004720 fertilization Effects 0.000 title claims description 14
- DZHMRSPXDUUJER-UHFFFAOYSA-N [amino(hydroxy)methylidene]azanium;dihydrogen phosphate Chemical compound NC(N)=O.OP(O)(O)=O DZHMRSPXDUUJER-UHFFFAOYSA-N 0.000 claims abstract description 33
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 33
- BVKZGUZCCUSVTD-UHFFFAOYSA-M Bicarbonate Chemical compound OC([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-M 0.000 claims abstract description 16
- 239000007787 solid Substances 0.000 claims abstract description 16
- 239000007864 aqueous solution Substances 0.000 claims abstract description 14
- 239000000126 substance Substances 0.000 claims abstract description 5
- 230000001105 regulatory effect Effects 0.000 claims abstract 2
- 235000015097 nutrients Nutrition 0.000 claims description 23
- 230000007935 neutral effect Effects 0.000 claims description 5
- 150000003839 salts Chemical class 0.000 claims description 3
- 239000002274 desiccant Substances 0.000 claims 1
- 239000000243 solution Substances 0.000 description 35
- 241000196324 Embryophyta Species 0.000 description 20
- 239000003337 fertilizer Substances 0.000 description 19
- 239000008233 hard water Substances 0.000 description 12
- 229910052698 phosphorus Inorganic materials 0.000 description 12
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 10
- 239000011575 calcium Substances 0.000 description 10
- 239000011574 phosphorus Substances 0.000 description 10
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 9
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 8
- UIIMBOGNXHQVGW-UHFFFAOYSA-M Sodium bicarbonate Chemical compound [Na+].OC([O-])=O UIIMBOGNXHQVGW-UHFFFAOYSA-M 0.000 description 8
- 239000000047 product Substances 0.000 description 8
- 239000002253 acid Substances 0.000 description 7
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 6
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 6
- LFVGISIMTYGQHF-UHFFFAOYSA-N ammonium dihydrogen phosphate Chemical compound [NH4+].OP(O)([O-])=O LFVGISIMTYGQHF-UHFFFAOYSA-N 0.000 description 6
- 229910000387 ammonium dihydrogen phosphate Inorganic materials 0.000 description 6
- 229910052791 calcium Inorganic materials 0.000 description 6
- 230000000694 effects Effects 0.000 description 6
- 230000012010 growth Effects 0.000 description 6
- 239000000203 mixture Substances 0.000 description 6
- 235000019837 monoammonium phosphate Nutrition 0.000 description 6
- 239000006012 monoammonium phosphate Substances 0.000 description 6
- 239000002244 precipitate Substances 0.000 description 6
- 229910052757 nitrogen Inorganic materials 0.000 description 5
- 229910052700 potassium Inorganic materials 0.000 description 5
- 239000012088 reference solution Substances 0.000 description 5
- UXVMQQNJUSDDNG-UHFFFAOYSA-L Calcium chloride Chemical compound [Cl-].[Cl-].[Ca+2] UXVMQQNJUSDDNG-UHFFFAOYSA-L 0.000 description 4
- 150000007513 acids Chemical class 0.000 description 4
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 4
- 229910000019 calcium carbonate Inorganic materials 0.000 description 4
- 239000001110 calcium chloride Substances 0.000 description 4
- 229910001628 calcium chloride Inorganic materials 0.000 description 4
- 229960004838 phosphoric acid Drugs 0.000 description 4
- 235000011007 phosphoric acid Nutrition 0.000 description 4
- 235000017557 sodium bicarbonate Nutrition 0.000 description 4
- 229910000030 sodium bicarbonate Inorganic materials 0.000 description 4
- 239000002689 soil Substances 0.000 description 4
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 3
- 239000012895 dilution Substances 0.000 description 3
- 238000010790 dilution Methods 0.000 description 3
- 229910052500 inorganic mineral Inorganic materials 0.000 description 3
- 239000011707 mineral Substances 0.000 description 3
- 235000010755 mineral Nutrition 0.000 description 3
- 230000008635 plant growth Effects 0.000 description 3
- 239000011591 potassium Substances 0.000 description 3
- 238000001556 precipitation Methods 0.000 description 3
- 239000003643 water by type Substances 0.000 description 3
- WCUXLLCKKVVCTQ-UHFFFAOYSA-M Potassium chloride Chemical compound [Cl-].[K+] WCUXLLCKKVVCTQ-UHFFFAOYSA-M 0.000 description 2
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 230000003139 buffering effect Effects 0.000 description 2
- OSGAYBCDTDRGGQ-UHFFFAOYSA-L calcium sulfate Chemical compound [Ca+2].[O-]S([O-])(=O)=O OSGAYBCDTDRGGQ-UHFFFAOYSA-L 0.000 description 2
- 239000004202 carbamide Substances 0.000 description 2
- 229940113601 irrigation solution Drugs 0.000 description 2
- 239000003621 irrigation water Substances 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 150000007524 organic acids Chemical class 0.000 description 2
- 235000005985 organic acids Nutrition 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- 229910019142 PO4 Inorganic materials 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 230000002730 additional effect Effects 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 230000001580 bacterial effect Effects 0.000 description 1
- 239000000872 buffer Substances 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000002178 crystalline material Substances 0.000 description 1
- 238000012364 cultivation method Methods 0.000 description 1
- 230000001627 detrimental effect Effects 0.000 description 1
- 239000003102 growth factor Substances 0.000 description 1
- 239000010440 gypsum Substances 0.000 description 1
- 229910052602 gypsum Inorganic materials 0.000 description 1
- 231100001261 hazardous Toxicity 0.000 description 1
- 239000003864 humus Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 230000000813 microbial effect Effects 0.000 description 1
- 150000007522 mineralic acids Chemical class 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 230000020477 pH reduction Effects 0.000 description 1
- 235000021317 phosphate Nutrition 0.000 description 1
- 150000003013 phosphoric acid derivatives Chemical class 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 230000037039 plant physiology Effects 0.000 description 1
- 230000008092 positive effect Effects 0.000 description 1
- XAEFZNCEHLXOMS-UHFFFAOYSA-M potassium benzoate Chemical compound [K+].[O-]C(=O)C1=CC=CC=C1 XAEFZNCEHLXOMS-UHFFFAOYSA-M 0.000 description 1
- 239000001103 potassium chloride Substances 0.000 description 1
- 235000011164 potassium chloride Nutrition 0.000 description 1
- OTYBMLCTZGSZBG-UHFFFAOYSA-L potassium sulfate Chemical compound [K+].[K+].[O-]S([O-])(=O)=O OTYBMLCTZGSZBG-UHFFFAOYSA-L 0.000 description 1
- 229910052939 potassium sulfate Inorganic materials 0.000 description 1
- 235000011151 potassium sulphates Nutrition 0.000 description 1
- 230000002786 root growth Effects 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
- 239000011701 zinc Substances 0.000 description 1
- -1 zinc metals Chemical class 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C05—FERTILISERS; MANUFACTURE THEREOF
- C05B—PHOSPHATIC FERTILISERS
- C05B17/00—Other phosphatic fertilisers, e.g. soft rock phosphates, bone meal
-
- C—CHEMISTRY; METALLURGY
- C05—FERTILISERS; MANUFACTURE THEREOF
- C05C—NITROGENOUS FERTILISERS
- C05C5/00—Fertilisers containing other nitrates
- C05C5/02—Fertilisers containing other nitrates containing sodium or potassium nitrate
-
- C—CHEMISTRY; METALLURGY
- C05—FERTILISERS; MANUFACTURE THEREOF
- C05G—MIXTURES OF FERTILISERS COVERED INDIVIDUALLY BY DIFFERENT SUBCLASSES OF CLASS C05; MIXTURES OF ONE OR MORE FERTILISERS WITH MATERIALS NOT HAVING A SPECIFIC FERTILISING ACTIVITY, e.g. PESTICIDES, SOIL-CONDITIONERS, WETTING AGENTS; FERTILISERS CHARACTERISED BY THEIR FORM
- C05G5/00—Fertilisers characterised by their form
- C05G5/20—Liquid fertilisers
- C05G5/23—Solutions
Definitions
- the present invention relates to a solid, acidic potassium nitrate by means of which properties of hard, alkaline water, such as the pH and bicarbonate content of the water, can be adjusted to correspond better to the growth requirements of plants.
- the invention also relates to an irrigation solution, prepared from this product and intended for the irrigation of plants.
- Plants require for their growth heat and sunlight, water and nutrients.
- the growth of plants is determined by the growth factor that is in the shortest supply relative to their need. To guarantee the growth possibilities, efforts are made to ensure plants a sufficient supply of water and nutrients.
- drip irrigation wherein the concentrations of nutrients in the irrigation water can be adjusted to correspond more precisely to the needs of plants at each given time has proven to be efficient with respect to the use of both water and nutrients.
- the efficiency of phosphorus in drip irrigation is considerably higher than the efficiency of a solid phosphorus fertilizer applied to the soil by local fertilizing.
- Drip irrigation has indeed become a popular cultivation method, for example, in the Mediterranean countries.
- the pH of a solution usable for irrigation fertilizing is preferably 5 - 7.
- a grower in order for a grower to know how to prepare such a solution for use, he should know the pH and buffering capacity of the raw water, the urea phosphate concentration in the solution, and the effect of the other fertilizers present in the solution on the pH value of the completed solution for use.
- the pH of even one and the same fertilizer for example mono- ammonium phosphate, may vary depending on the preparation process of the product and the raw materials used therein.
- Potassium chloride is used less because of its detrimentally high chloride content.
- Potassium sulfate for its part, cannot be used if the raw water contains a large amount of calcium, which precipitates as calcium sulfate, i.e. gypsum.
- Potassium nitrate is used either alone or in fertilizer mixtures together with other nutrient salts to provide the desired nutrient proportions. It is also common that growers themselves prepare from different fertilizers the solutions they need for use.
- a plant thrives best in an environment having a pH of approx. 5 - 7. Within this pH range most nutrients are in a form usable by plants. In an alkaline environment there occurs precipitation of secondary and trace nutrients in the form of phosphates or other compounds. At a low pH (pH ⁇ 5), on the other hand, the concentration of, for example, aluminum in the soil solution increases sharply. This has detrimental effects on plant roots. In general a pH range of 5.5 - 6.5 is advantageous for root growth, which in turn is a prerequisite for plant growth (Taiz L., Zaiger E., Plant Physiology, 1991, p. 105; Kluwer Academic Publishers, Fertilizer Manual, 1998, p. 24 - 26).
- Drip irrigation fertilization is one of the most efficient forms of fertilization. Problems may, however, appear when precipitates (e.g. CaC0 3 ) are formed from alkaline and hard waters on pipe walls and in nozzles. The problem is emphasized in particular in sub-surface drip irrigation (SDI) pipes.
- SDI sub-surface drip irrigation
- an aqueous solution usable for irrigation fertilizing of plants the solution being formed from a solid potassium nitrate acidified with urea phosphate and from neutral or alkaline water and containing the said acidic potassium nitrate in an amount of 0.01 - 0.3 % by weight of potassium nitrate.
- a solid, acidic potassium nitrate product for controlling the chemical properties of neutral or alkaline water and for preparing an aqueous solution intended for irrigation fertilization of plants, the potassium nitrate product comprising 85 - 98 % by weight of potassium nitrate and 2 - 15 % by weight of urea phosphate.
- the invention relates preferably to a solid, acidic potassium nitrate by means of which the pH and bicarbonate concentration of hard, alkaline water can be adjusted to correspond better to the growth requirements of plants.
- the acidic potassium nitrate according to the invention contains at maximum 15 % by weight of urea phos- phate.
- the invention also relates to an at maximum 0.3 % (w/w) solution for use, containing an acidic potassium nitrate.
- Acidic potassium nitrate used in accordance with the invention may be a mixture of crystalline materials, a granular product.
- the acidic potassium nitrate according to the invention can be prepared, for example, simply by mixing a crystalline urea phosphate and a crystalline potassium ni- trate at the said weight ratios.
- Potassium nitrate acidified with urea phosphate thus has a positive effect on the dissolving of both phosphorus and secondary and trace nutrients, and it thereby also improves the ability of plants to use these nutrients.
- irrigation solutions containing it are not too acidic, for example, for use in drip irrigation. Also, when the product according to the invention is used, separate equipment associated with the adding of acid are not necessary.
- an approx. 10 % (w/w) solution for storage which is then further diluted to an approx. 0.01 - 0.3 % (w/w) solution for use.
- the acidic potassium nitrate according to the invention which con- tains urea phosphate 2 - 15 % (w/w), may also be used as dilutions of 0.01 - 0.3 % (w/w), preferably as dilutions of 0.05 - 0.3 % (w/w), when the pH of the available raw water is 7 - 9 and its bicarbonate concentration is 170 - 350 ppm HCO .
- the use of the acidic potassium nitrate is especially advantageous with a medium-hard water having a pH of 7 - 9 and a bicarbonate concentration of 170 - 250 ppm HCO 3 .
- the pH of a solution used in drip irrigation can be adjusted, by means of a 0.01 - 0.3 % aqueous solution of potassium nitrate acidified with urea phosphate, to a pH range within which CaC0 3 precipitates do not form.
- the proportion of potassium nitrate varies, but it is typically approx. one-half or more than one-half of the total amount of the fertilizer.
- the adding of urea phosphate to potassium nitrate, i.e. the acidification of potassium nitrate thus makes it possible to regulate the pH of conventional fertilizer solutions (nutrient concentration ⁇ 0.3 %; KN0 3 over 50 % (w/w) of the solids) used in irrigation fertilization.
- the acidic potassium nitrate solution automatically adjusts to the correct level the pH of the solution used where medium hard water is avail- able.
- Such areas exist in, for example, the Mediterranean countries, South America and Australia.
- the use of the acidic potassium nitrate is possible also when the phosphorus requirement of a plant is low. If, on the other hand, the phosphorus requirement of a plant is higher, any phosphorus fertilizer suitable for irrigation fertilization can be used for additional fertilization.
- Table 1 shows the nutrient composition of the acidic potassium nitrate according to the invention as the amount of urea phosphate (UP) present in it varies.
- the other advantages of the acidic potassium nitrate include a good physical quality, since both components absorb moisture only a little or not at all.
- urea phosphate on metals (e.g. copper and zinc metals) is also considerably less than that of the mineral acids used for corresponding purposes.
- the advantageousness of urea phosphate is emphasized when the solution contains a large amount of potassium nitrate (Corros. Sci. (1976), 16(8), 485-98).
- phosphoric acid has a strongly buffering char- acter.
- pH 8 the pH of alkaline water
- the pH of alkaline water e.g. pH 8
- the pH of alkaline water can be lowered rapidly and effectively to the desired range ( ⁇ pH 7), but owing to the buffer effect the pH will, however, remain within a range of pH 5 - 7.
- a synthetic, medium-hard water having a bicarbonate concentration of 175 ppm HC0 3 , a calcium concentration of 82 ppm Ca and a pH of 7.2 was prepared by adding 241 mg of sodium bicarbonate and 160 mg of calcium chloride to one liter of ion-exchanged water.
- a synthetic, medium-hard water having a bicarbonate concentration of 250 ppm HCO 3 , a calcium concentration of 82 ppm Ca, and a pH of 7 was prepared by adding 344 mg of sodium bicarbonate and 228 mg of calcium chloride to one liter of ion-exchanged water.
- a synthetic, rather hard water having a bicarbonate concentration of 300 ppm HC0 3 , calcium concentration of 99 ppm Ca and a pH of 7 was prepared by adding 413 mg/liter of sodium bicarbonate and 274 mg/liter of calcium chloride to ion- exchanged water.
- a synthetic, rather hard water having a bicarbonate concentration of 330 ppm HCO 3 , a calcium concentration of 109 ppm Ca and a pH of 7 was prepared by adding 454 mg/liter of sodium bicarbonate and 301 mg/liter of calcium chloride to ion- exchanged water.
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Pest Control & Pesticides (AREA)
- Fertilizers (AREA)
Abstract
A solid, acidic potassium nitrate containing 2-15 % by weight of urea phosphate is intended for regulating the chemical properties, such as the pH and bicarbonate concentration, of hard alkaline water. From the solid potassium nitrate acidified with urea phosphate it is possible to form an aqueous solution that can be used for the irrigation of plants.
Description
ACIDIC POTASSIUM NITRATE FOR IRRIGATION FERTILIZATION OF PLANTS
The present invention relates to a solid, acidic potassium nitrate by means of which properties of hard, alkaline water, such as the pH and bicarbonate content of the water, can be adjusted to correspond better to the growth requirements of plants. The invention also relates to an irrigation solution, prepared from this product and intended for the irrigation of plants.
State of the art
Plants require for their growth heat and sunlight, water and nutrients. The growth of plants is determined by the growth factor that is in the shortest supply relative to their need. To guarantee the growth possibilities, efforts are made to ensure plants a sufficient supply of water and nutrients.
Not only ensuring a sufficient supply of water, but also ensuring a supply of irrigation water of specifically the correct quality in terms of plant growth, may be prob- lematic. It is particularly problematic when the soil is calcareous and alkaline. In this case the raw water also contains dissolved calcium and bicarbonate, which render it alkaline and hard, and thus less suitable for the irrigation of plants.
Of the various irrigation methods, drip irrigation wherein the concentrations of nutrients in the irrigation water can be adjusted to correspond more precisely to the needs of plants at each given time has proven to be efficient with respect to the use of both water and nutrients. For example, the efficiency of phosphorus in drip irrigation is considerably higher than the efficiency of a solid phosphorus fertilizer applied to the soil by local fertilizing. Drip irrigation has indeed become a popular cultivation method, for example, in the Mediterranean countries.
In drip irrigation, technical problems may be incurred from the use of hard and alkaline water, for example, as calcium carbonate (CaC03) forms precipitations on the walls of the irrigation pipes and the nozzles. This problem is especially emphasized in sub-surface drip irrigation (SDI) pipes.
In practice, attempts have been made to solve this problem by dissolving precipita- tions formed in pipes by means of strong mineral acids, such as nitric acid or phosphoric acid. Being strong liquid acids they are not only difficult to handle but also hazardous to people and the environment. Solid inorganic acids, such as solid phos-
phoric acid hemihydrate (melting point 29.3 °C, CRH 9 % RH), are also out of the question because of their disadvantageous physical properties.
From patent application WO 01/25168 there is known a solid water-soluble fertilizer composition that contains, in addition to fertilizers, also a phosphorus-free or- ganic acid to control the pH of the water. However, in nutrient solutions organic acids may act as nutrients for microbes; there forms slimy microbial growth that clogs the nozzles of the irrigation equipment. Furthermore, organic substances are not compatible with oxidizing substances such as potassium nitrate. Since organic acids are expensive and do not contain nutrients necessary for plants, their use causes only futile expense.
The adding of solid urea phosphate to irrigation fertilizers has been a clear improvement in preventing the formation of precipitates. Simultaneously with the addition of nitrogen and phosphorus as nutrients to the solution, also the pH of the solution will be adjusted to an acidic value and the formation of precipitates will be presented. Such an option has been disclosed by, for example, R.L. Mikkelsen (Soil Sci. Soc. Am. J. 1987 51 :2 464-468).
From patent publication ZA 7507914 (Triomf Fertilizers Ltd) there is known a method for the preparation of a solid, acid NPK mixed fertilizer, wherein the raw materials are urea, a strong phosphoric acid solution and potassium nitrate.
It is known that the pH of a solution usable for irrigation fertilizing is preferably 5 - 7. However, in order for a grower to know how to prepare such a solution for use, he should know the pH and buffering capacity of the raw water, the urea phosphate concentration in the solution, and the effect of the other fertilizers present in the solution on the pH value of the completed solution for use. There is also the addi- tional drawback that the pH of even one and the same fertilizer, for example mono- ammonium phosphate, may vary depending on the preparation process of the product and the raw materials used therein.
Most irrigation fertilized plants require of the principal nutrients (N, P, K) potassium relatively the most, nitrogen slightly less and phosphorus the least. For this reason, potassium nitrate is indeed an ideal nutrient salt for use as a source of nitrogen and potassium in irrigation fertilization.
Both in the cultivation of garden plants and in greenhouses the most common potassium salt even in drip irrigation cultivation is potassium nitrate. Potassium chloride is used less because of its detrimentally high chloride content. Potassium sulfate, for
its part, cannot be used if the raw water contains a large amount of calcium, which precipitates as calcium sulfate, i.e. gypsum.
Potassium nitrate is used either alone or in fertilizer mixtures together with other nutrient salts to provide the desired nutrient proportions. It is also common that growers themselves prepare from different fertilizers the solutions they need for use.
For good growth a plant needs not only water and the principal nutrients N, P and K, but also secondary and trace nutrients. It is known that the availability of both phosphorus and trace nutrients largely depends on the pH (Kluwer Academic Pub- lishers, Fertilizer Manual, 1998, pp. 24-26).
A plant thrives best in an environment having a pH of approx. 5 - 7. Within this pH range most nutrients are in a form usable by plants. In an alkaline environment there occurs precipitation of secondary and trace nutrients in the form of phosphates or other compounds. At a low pH (pH <5), on the other hand, the concentration of, for example, aluminum in the soil solution increases sharply. This has detrimental effects on plant roots. In general a pH range of 5.5 - 6.5 is advantageous for root growth, which in turn is a prerequisite for plant growth (Taiz L., Zaiger E., Plant Physiology, 1991, p. 105; Kluwer Academic Publishers, Fertilizer Manual, 1998, p. 24 - 26).
Drip irrigation fertilization is one of the most efficient forms of fertilization. Problems may, however, appear when precipitates (e.g. CaC03) are formed from alkaline and hard waters on pipe walls and in nozzles. The problem is emphasized in particular in sub-surface drip irrigation (SDI) pipes.
Description of the invention
As a solution to the problems described above it has been invented to add urea phosphate to potassium nitrate. Owing to the sufficient acidity of urea phosphate, the amounts of urea phosphate used are small and do not restrict the use of conventional fertilizer compositions in irrigation fertilization. With 0.01 - 0.3 % (w/w) aqueous solutions of potassium nitrate acidified with urea phosphate it is possible to adjust the pH of the raw water according to the hardness of the water to a range wherein no CaC03 precipitates are formed and whereby the problems caused by humus and slimy bacterial covers are also eliminated.
According to the present invention, there is thus provided an aqueous solution usable for irrigation fertilizing of plants, the solution being formed from a solid potassium nitrate acidified with urea phosphate and from neutral or alkaline water and containing the said acidic potassium nitrate in an amount of 0.01 - 0.3 % by weight of potassium nitrate.
According to the invention there is also provided a solid, acidic potassium nitrate product for controlling the chemical properties of neutral or alkaline water and for preparing an aqueous solution intended for irrigation fertilization of plants, the potassium nitrate product comprising 85 - 98 % by weight of potassium nitrate and 2 - 15 % by weight of urea phosphate.
Thus the invention relates preferably to a solid, acidic potassium nitrate by means of which the pH and bicarbonate concentration of hard, alkaline water can be adjusted to correspond better to the growth requirements of plants. The acidic potassium nitrate according to the invention contains at maximum 15 % by weight of urea phos- phate. The invention also relates to an at maximum 0.3 % (w/w) solution for use, containing an acidic potassium nitrate. Acidic potassium nitrate used in accordance with the invention may be a mixture of crystalline materials, a granular product.
The acidic potassium nitrate according to the invention can be prepared, for example, simply by mixing a crystalline urea phosphate and a crystalline potassium ni- trate at the said weight ratios.
Potassium nitrate acidified with urea phosphate thus has a positive effect on the dissolving of both phosphorus and secondary and trace nutrients, and it thereby also improves the ability of plants to use these nutrients. However, irrigation solutions containing it are not too acidic, for example, for use in drip irrigation. Also, when the product according to the invention is used, separate equipment associated with the adding of acid are not necessary.
In general, for irrigation fertilization there is first prepared an approx. 10 % (w/w) solution for storage, which is then further diluted to an approx. 0.01 - 0.3 % (w/w) solution for use. The acidic potassium nitrate according to the invention, which con- tains urea phosphate 2 - 15 % (w/w), may also be used as dilutions of 0.01 - 0.3 % (w/w), preferably as dilutions of 0.05 - 0.3 % (w/w), when the pH of the available raw water is 7 - 9 and its bicarbonate concentration is 170 - 350 ppm HCO . The use of the acidic potassium nitrate is especially advantageous with a medium-hard
water having a pH of 7 - 9 and a bicarbonate concentration of 170 - 250 ppm HCO3.
The use of the product according to the invention for irrigation fertilizing purposes is, however, not limited only to hard water; it is also suitable for use with soft wa- ters as long as the correct dilution proportions are taken into account.
The pH of a solution used in drip irrigation can be adjusted, by means of a 0.01 - 0.3 % aqueous solution of potassium nitrate acidified with urea phosphate, to a pH range within which CaC03 precipitates do not form.
Together with the product it is possible to use in irrigation fertilization also other common fertilizers, such as urea and/or monoammonium phosphate (MAP), as long as care is at the same time taken that the total nutrient concentration in the irrigation solution remains below 0.3 % (w/w).
In fertilizer compositions the proportion of potassium nitrate varies, but it is typically approx. one-half or more than one-half of the total amount of the fertilizer. The adding of urea phosphate to potassium nitrate, i.e. the acidification of potassium nitrate, thus makes it possible to regulate the pH of conventional fertilizer solutions (nutrient concentration <0.3 %; KN03 over 50 % (w/w) of the solids) used in irrigation fertilization. The acidic potassium nitrate solution automatically adjusts to the correct level the pH of the solution used where medium hard water is avail- able. Such areas exist in, for example, the Mediterranean countries, South America and Australia.
Owing to its low phosphorus content, the use of the acidic potassium nitrate is possible also when the phosphorus requirement of a plant is low. If, on the other hand, the phosphorus requirement of a plant is higher, any phosphorus fertilizer suitable for irrigation fertilization can be used for additional fertilization.
Table 1 shows the nutrient composition of the acidic potassium nitrate according to the invention as the amount of urea phosphate (UP) present in it varies.
Table 1
The other advantages of the acidic potassium nitrate include a good physical quality, since both components absorb moisture only a little or not at all.
The corrosive action of urea phosphate on metals (e.g. copper and zinc metals) is also considerably less than that of the mineral acids used for corresponding purposes. The advantageousness of urea phosphate is emphasized when the solution contains a large amount of potassium nitrate (Corros. Sci. (1976), 16(8), 485-98).
Compared with other mineral acids, phosphoric acid has a strongly buffering char- acter. In practice this means that, when a potassium nitrate acidified with urea phosphate is added, the pH of alkaline water (e.g. pH 8) can be lowered rapidly and effectively to the desired range (< pH 7), but owing to the buffer effect the pH will, however, remain within a range of pH 5 - 7.
For the pH control of especially hard waters (e.g. 250 - 350 ppm HC03) it is possi- ble to use either stronger solutions of acidic potassium nitrate (e.g. 0.2 - 0.3 % (w/w)) or an acidic potassium nitrate containing relatively more urea phosphate.
The invention is defined in greater detail in claims 1 - 10.
The following examples are intended for elucidating the invention without limiting it in any manner.
Example 1
Comparison of acidic potassium nitrate solutions
Two fertilizer solution series were prepared in ion-exchanged water, one series containing potassium nitrate acidified with urea phosphate and the other potassium nitrate acidified with monoammonium phosphate.
The pH values of the solutions were measured. The results of the measurements are shown in Table 2.
Table 2
The results show that, when the same amounts of monoammonium phosphate and urea phosphate are added to potassium nitrate, a considerably greater pH change is obtained with potassium nitrate acidified with urea phosphate than with potassium nitrate acidified with monoammonium phosphate.
Example 2 Effect of acidic potassium nitrate on medium-hard water
A synthetic, medium-hard water having a bicarbonate concentration of 175 ppm HC03, a calcium concentration of 82 ppm Ca and a pH of 7.2 was prepared by adding 241 mg of sodium bicarbonate and 160 mg of calcium chloride to one liter of ion-exchanged water.
From five potassium nitrates acidified with different urea phosphate amounts a series of solutions was prepared in the synthetic, medium-hard water mentioned above. The reference solutions were prepared from pure potassium nitrate. The pH values of the solutions were measured. The results of the measurements are shown in Table 3.
Table 3
(*pH of the raw water approx. 7)
Example 3
Effect of acidic potassium nitrate on medium-hard water
A synthetic, medium-hard water having a bicarbonate concentration of 250 ppm HCO3, a calcium concentration of 82 ppm Ca, and a pH of 7 was prepared by adding 344 mg of sodium bicarbonate and 228 mg of calcium chloride to one liter of ion-exchanged water.
From four potassium nitrates acidified with different urea phosphate amounts a series of solutions were prepared in this water. The solution concentrations were within the range 0.1 - 0.3 %. Reference solutions containing only potassium nitrate were prepared. The pH values of the solutions were measured, and the results are shown in Table 4.
Table 4
Effect of acidic potassium nitrate on rather hard water
A synthetic, rather hard water having a bicarbonate concentration of 300 ppm HC03, calcium concentration of 99 ppm Ca and a pH of 7 was prepared by adding 413 mg/liter of sodium bicarbonate and 274 mg/liter of calcium chloride to ion- exchanged water.
From four potassium nitrates acidified with different urea phosphate amounts solutions of 0.2 - 0.3 % were prepared in this water. Reference solutions containing only potassium nitrate were prepared. The pH values of the solutions were measured, and the results are shown in Table 5.
Table 5
Example 5
Effect of acidic potassium nitrate on rather hard water
A synthetic, rather hard water having a bicarbonate concentration of 330 ppm HCO3, a calcium concentration of 109 ppm Ca and a pH of 7 was prepared by adding 454 mg/liter of sodium bicarbonate and 301 mg/liter of calcium chloride to ion- exchanged water.
From two potassium nitrates acidified with different urea phosphate amounts solu- tions of 0.05 - 0.3 % were prepared in this water. Reference solutions containing only potassium nitrate were prepared. The pH values of the solutions were measured, and the results are shown in Table 6.
Table 6
On the basis of the tests performed it can be stated that with the help of acidified potassium nitrate it was possible to adjust the acidity of waters of different levels of hardness (pH approx. 7) to a pH suitable for the irrigation of plants. Reference solutions containing only potassium nitrate surprisingly raised the pH of water to 8.
Claims
1. An aqueous solution for use for irrigation fertilization of plants, characterized in that it is formed from a solid potassium nitrate acidified with urea phosphate and from a neutral or alkaline water, and that it contains the said acidic potassium nitrate in an amount of 0.01 - 0.3 % by weight.
2. The aqueous solution according to claim 1, characterized in that it is formed from a hard neutral or alkaline water having a pH of 7 - 9 and a bicarbonate concentration of 175 - 350 ppm HC03, preferably 175 - 250 ppm HC03.
3. The aqueous solution according to claim 1 or 2, characterized in that the solid potassium nitrate acidified with urea phosphate comprises 85 - 98 % by weight of potassium nitrate and 2 - 15 % by weight of urea phosphate.
4. The aqueous solution according to any of the preceding claims, characterized in that its pH is 5 - 7.
5. The aqueous solution according to claim 4, characterized in that its pH is 6 - 7.
6. The aqueous solution according to any of the preceding claims, characterized in that its bicarbonate concentration is lower than 150 ppm HCO3.
7. The aqueous solution according to any of the preceding claims, characterized in that it additionally contains other nutrient salts.
8. The use of an aqueous solution according to any of the preceding claims in drip irrigation.
9. A solid acidic potassium nitrate product for regulating the chemical properties of neutral or alkaline water and for preparing an aqueous solution intended for the irrigation fertilization of plants, characterized in that it comprises 85 - 98 % by weight of potassium nitrate and 2 - 15 % by weight of urea phosphate.
10. The potassium nitrate product according to claim 9, characterized in that it contains a desiccant.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU2003201426A AU2003201426A1 (en) | 2002-01-15 | 2003-01-15 | Acidic potassium nitrate for irrigation fertilization of plants |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FI20020070 | 2002-01-15 | ||
| FI20020070A FI112938B (en) | 2002-01-15 | 2002-01-15 | Acid potassium nitrate |
Related Child Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US14/403,023 A-371-Of-International US9458128B2 (en) | 2012-05-24 | 2013-05-23 | Catechol O-methyltransferase activity inhibiting compounds |
| US15/226,579 Continuation US20170165219A1 (en) | 2012-05-24 | 2016-08-02 | Catechol o-methyltransferase activity inhibiting compounds |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2003059845A1 true WO2003059845A1 (en) | 2003-07-24 |
Family
ID=8562786
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/FI2003/000026 WO2003059845A1 (en) | 2002-01-15 | 2003-01-15 | Acidic potassium nitrate for irrigation fertilization of plants |
Country Status (3)
| Country | Link |
|---|---|
| AU (1) | AU2003201426A1 (en) |
| FI (1) | FI112938B (en) |
| WO (1) | WO2003059845A1 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| ES2337000A1 (en) * | 2008-10-17 | 2010-04-19 | Herogra Fertilizantes, S.A. | Unlocking product of nutrients for fertirrigation (Machine-translation by Google Translate, not legally binding) |
| ES2336999A1 (en) * | 2008-10-17 | 2010-04-19 | Herogra Fertilizantes, S.A. | Unlocking product of nutrients for fertirrigation (Machine-translation by Google Translate, not legally binding) |
| ES2337001A1 (en) * | 2008-10-17 | 2010-04-19 | Herogra Fertilizantes, S.A. | Unlocking product of nutrients for fertirrigation (Machine-translation by Google Translate, not legally binding) |
| CN111233556A (en) * | 2020-03-20 | 2020-06-05 | 贵州川恒化工股份有限公司 | Urea phosphate mother liquor slow-release suspension liquid fertilizer and preparation method thereof |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4013446A (en) * | 1974-12-20 | 1977-03-22 | Fertilizers & Chemicals Ltd. | Method for preventing creasing in citrus fruit |
| US4145208A (en) * | 1977-01-12 | 1979-03-20 | Fertilizers & Chemicals Ltd. | Method and composition for improving the functioning of drip irrigation systems |
| US5851260A (en) * | 1994-04-15 | 1998-12-22 | Kemira Agro Oy | Suspension fertilizer suitable for irrigation fertilization, and a process for its preparation |
| US5997602A (en) * | 1995-06-22 | 1999-12-07 | Kemira Agro Oy | Aqueous fertilzer suspension containing at least phosphate ions and calcium or magnesium ions and a use of the suspension |
| US6312493B1 (en) * | 1999-10-07 | 2001-11-06 | Oms Investments, Inc. | Water soluble fertilizer compositions |
-
2002
- 2002-01-15 FI FI20020070A patent/FI112938B/en not_active IP Right Cessation
-
2003
- 2003-01-15 WO PCT/FI2003/000026 patent/WO2003059845A1/en not_active Application Discontinuation
- 2003-01-15 AU AU2003201426A patent/AU2003201426A1/en not_active Abandoned
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4013446A (en) * | 1974-12-20 | 1977-03-22 | Fertilizers & Chemicals Ltd. | Method for preventing creasing in citrus fruit |
| US4145208A (en) * | 1977-01-12 | 1979-03-20 | Fertilizers & Chemicals Ltd. | Method and composition for improving the functioning of drip irrigation systems |
| US5851260A (en) * | 1994-04-15 | 1998-12-22 | Kemira Agro Oy | Suspension fertilizer suitable for irrigation fertilization, and a process for its preparation |
| US5997602A (en) * | 1995-06-22 | 1999-12-07 | Kemira Agro Oy | Aqueous fertilzer suspension containing at least phosphate ions and calcium or magnesium ions and a use of the suspension |
| US6312493B1 (en) * | 1999-10-07 | 2001-11-06 | Oms Investments, Inc. | Water soluble fertilizer compositions |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| ES2337000A1 (en) * | 2008-10-17 | 2010-04-19 | Herogra Fertilizantes, S.A. | Unlocking product of nutrients for fertirrigation (Machine-translation by Google Translate, not legally binding) |
| ES2336999A1 (en) * | 2008-10-17 | 2010-04-19 | Herogra Fertilizantes, S.A. | Unlocking product of nutrients for fertirrigation (Machine-translation by Google Translate, not legally binding) |
| ES2337001A1 (en) * | 2008-10-17 | 2010-04-19 | Herogra Fertilizantes, S.A. | Unlocking product of nutrients for fertirrigation (Machine-translation by Google Translate, not legally binding) |
| CN111233556A (en) * | 2020-03-20 | 2020-06-05 | 贵州川恒化工股份有限公司 | Urea phosphate mother liquor slow-release suspension liquid fertilizer and preparation method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| FI20020070L (en) | 2003-07-16 |
| FI112938B (en) | 2004-02-13 |
| AU2003201426A1 (en) | 2003-07-30 |
| FI20020070A0 (en) | 2002-01-15 |
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