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)

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Cited By (4)

Citations (5)

• 2002
  • 2002-01-15 FI FI20020070A patent/FI112938B/sv 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)

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