WO1995018081A1 - Urea-containing fertilizer - Google Patents

Urea-containing fertilizer Download PDF

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Publication number
WO1995018081A1
WO1995018081A1 PCT/NO1994/000212 NO9400212W WO9518081A1 WO 1995018081 A1 WO1995018081 A1 WO 1995018081A1 NO 9400212 W NO9400212 W NO 9400212W WO 9518081 A1 WO9518081 A1 WO 9518081A1
Authority
WO
WIPO (PCT)
Prior art keywords
urea
nitrate
fertilizer
complex
ferric nitrate
Prior art date
Application number
PCT/NO1994/000212
Other languages
French (fr)
Inventor
Ian Richards
Original Assignee
Norsk Hydro A.S
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Norsk Hydro A.S filed Critical Norsk Hydro A.S
Priority to AU14274/95A priority Critical patent/AU1427495A/en
Publication of WO1995018081A1 publication Critical patent/WO1995018081A1/en

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C05—FERTILISERS; MANUFACTURE THEREOF
    • C05C—NITROGENOUS FERTILISERS
    • C05C1/00—Ammonium nitrate fertilisers
    • C—CHEMISTRY; METALLURGY
    • C05—FERTILISERS; MANUFACTURE THEREOF
    • C05C—NITROGENOUS FERTILISERS
    • C05C5/00—Fertilisers containing other nitrates
    • C—CHEMISTRY; METALLURGY
    • C05—FERTILISERS; MANUFACTURE THEREOF
    • C05C—NITROGENOUS FERTILISERS
    • C05C9/00—Fertilisers containing urea or urea compounds
    • 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
    • C05G3/00—Mixtures of one or more fertilisers with additives not having a specially fertilising activity
    • C05G3/90—Mixtures of one or more fertilisers with additives not having a specially fertilising activity for affecting the nitrification of ammonium compounds or urea in the soil
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P60/00—Technologies relating to agriculture, livestock or agroalimentary industries
    • Y02P60/20—Reduction of greenhouse gas [GHG] emissions in agriculture, e.g. CO2
    • Y02P60/21—Dinitrogen oxide [N2O], e.g. using aquaponics, hydroponics or efficiency measures

Definitions

  • Urea-containing fertilizer containing at least one urease inhibitor comprising metal nitrate.
  • Rapid hydrolysis takes place upon surface application of urea to soil as a result of the influence of the naturally occurring enzyme urease. This can lead to undesirable loss of nitrogen in the form of ammonia to the atmosphere.
  • the end result of this rapid hydrolysis is to produce a solution high in pH and ammonia/ammonium content at the soil fertilizer reaction site. This in turn can lead to several problems including damage to germinating seedlings or young plants.
  • Scorching of plants is a special problem related to the amount of ammonia present and might where fertilizer is applied to the soil limit the amount of fertilizer that can be applied. This problem can be solved if the fertilizer is placed in bands to the side of the crop and thereby avoiding injury to young plants. Such practice is common in some countries, but is often considered impractical and it will not work for well established crops like grass to which urea must be surface applied.
  • Scorch also occurs where urea or urea-containing fertilizers are applied to plant leaves in liquid solutions or suspensions. Again, this is related to the formation of ammonia with consequent damage to the leaves. Numerous attempts have been made to reduce undesired hydrolysis of urea, especially at the very beginning of the application of the urea fertilizer.
  • Several urease inhibitors are known in the art.
  • WO 90/11262 there is described a urea based fertilizer, especially for foliar application.
  • divalent cationic monovalent anionic metal salts are added to the liquid urea fertilizer.
  • Preferred salts are magnesium, calcium or zinc chlorides/nitrates.
  • metal salts of variable valency state i.e. Fe, Ni, Mn, Co, Cu, were found to decompose in the presence of urea to form complex oxides and hydroxides and were accordingly not considered suitable for the intended purpose.
  • the main object of the present invention was to arrive at urea fertilizers comprising compounds that would inhibit more efficiently than known compounds the native soil urease and which also could be used without substantial risk of plant scorch.
  • Another object was to find inhibitors that could reduce the ammonia loss from urea by a minimum of 50% over a time period of one week.
  • a further object was to arrive at a urea fertilizer having low ammonia loss when applied either in the form of solid fertilizer or of liquid fertilizer, especially urea-ammonium nitrate (UAN) solutions.
  • UAN urea-ammonium nitrate
  • the inventors decided to investigate further application of metal nitrates. Though the anion is considered largely unimportant, nitrates were chosen in view of their agronomic value. Sulphate anions were found to be effective, but less so than nitrate and chlorides were found to behave similarly to nitrates.
  • Hydrated ferric nitrate forms complexes with urea according to the following formula:
  • the ratio of ferric nitrate to urea may vary.
  • Ferric nitrate usually will be the preferred additive. However, depending on the soil on which the fertilizer is to be applied, aluminium nitrate might be preferred.
  • This example describes ammonia loss from soil with surface applied fertilizers. Ammonia losses relative to urea were investigated for 10 cations and one anion (borate). The tests were performed in 12 pairs of glass jars containing fresh soil which was light sandy loam. Prior to the tests the moisture content of the soil was adjusted to about 10%. Nitrogenous fertilizers, urea, ammonium nitrate or a metal salt-urea complex of known analysis were added to provide 0.149 mg N, which corresponds to approximately 175 kg ha-1 on a surface basis. Released ammonia was collected in bottles containing standardized acid whereby the ammonia loss could be calculated by standard methods. The tests were performed at about 20°C and were carried out over a period of 6 days.
  • Nitrates were chosen as anions except for copper where this was not possible.
  • the metal nitrates were added as solids to urea prior to particulation.
  • the metal : urea ratio was fixed at 1:6 for all the metal salt-urea complexes.
  • the experiments were performed as described in example 1.
  • the results are shown as function of time(days) in fig. 2.
  • the effects for the iron complex were substantially greater than for the copper complex.
  • This example shows the effect of iron-urea complexes containing none or some free urea.
  • the results are compared to those obtained for ammonium nitrate and urea as function of time (days). The effect is stated as % N lost as ammonia, cumulative.
  • the results are shown in fig. 3.
  • the best results were obtained when no free urea was present (“Fe2”), but even with 3 moles free urea for each ferric nitrate-urea complex (“Fe6”) the results are excellent, especially for the first 7 days.
  • the results also show that the metal needs not to be bound to urea to be effective. Further tests showed that even with relatively low contents of ferric/aluminium nitrate in the urea fertilizer the reduction in ammonia losses was substantial compared to conventional urease inhibitors.
  • the new fertilizers according to the invention were also tested with regard to phytotoxicity.
  • Three alkaline soils were used, two of which had high free lime contents.
  • Assessment was made by con-secutive emergent plant counts over a period.
  • Three ratios of urea with ferric nitrate and one of urea with aluminium nitrate were examined.
  • Urea had a highly depressive effect on plant emergence which was overcome equally by all the metal salt ratios tested giving effects similar to that of ammonium nitrate.

Abstract

The present invention relates to urea-containing fertilizer containing at least one urease inhibitor comprising metal nitrate. The fertilizer contains ferric nitrate and/or aluminium nitrate-urea complexes or the fertilizer contains both ferric nitrate and urea and urea or aluminium nitrate and urea. the fertilizer may be in the form of a liquid urea-ammonium nitrate solution or slurry. The molar ratio ferric nitrate-urea complex: urea in said fertilizer should be in the range of 1:1 to 1:15 and the molar ratio aluminium nitrate-urea complex: urea should be in the range of 1:1 to 1:18.

Description

Urea-containing fertilizer
Urea-containing fertilizer containing at least one urease inhibitor comprising metal nitrate.
Rapid hydrolysis takes place upon surface application of urea to soil as a result of the influence of the naturally occurring enzyme urease. This can lead to undesirable loss of nitrogen in the form of ammonia to the atmosphere. The end result of this rapid hydrolysis is to produce a solution high in pH and ammonia/ammonium content at the soil fertilizer reaction site. This in turn can lead to several problems including damage to germinating seedlings or young plants.
Scorching of plants is a special problem related to the amount of ammonia present and might where fertilizer is applied to the soil limit the amount of fertilizer that can be applied. This problem can be solved if the fertilizer is placed in bands to the side of the crop and thereby avoiding injury to young plants. Such practice is common in some countries, but is often considered impractical and it will not work for well established crops like grass to which urea must be surface applied.
Scorch also occurs where urea or urea-containing fertilizers are applied to plant leaves in liquid solutions or suspensions. Again, this is related to the formation of ammonia with consequent damage to the leaves. Numerous attempts have been made to reduce undesired hydrolysis of urea, especially at the very beginning of the application of the urea fertilizer. Several urease inhibitors are known in the art. In the patent application WO 90/11262 there is described a urea based fertilizer, especially for foliar application. In order to make the urea urease resistant divalent cationic monovalent anionic metal salts are added to the liquid urea fertilizer. Preferred salts are magnesium, calcium or zinc chlorides/nitrates. According to this application metal salts of variable valency state, i.e. Fe, Ni, Mn, Co, Cu, were found to decompose in the presence of urea to form complex oxides and hydroxides and were accordingly not considered suitable for the intended purpose.
It is further known from US-Patent No. 4,559,076 that ammonia volatilisation from urea may be reduced by simultaneously applying alkali or alkaline earth metal salts, such as chlorides, nitrates and sulphates to the soil.
However, none of the above methods were found to be acceptable from economical and environmental points of view. Many known inhibitors proved to be effective with regard to pure urease in aqueous solutions, but were not correspondingly effective in native soil urease. Inhibitors like alkali earth metal nitrates were found to give far too small reductions in ammonia losses.
The main object of the present invention was to arrive at urea fertilizers comprising compounds that would inhibit more efficiently than known compounds the native soil urease and which also could be used without substantial risk of plant scorch.
Another object was to find inhibitors that could reduce the ammonia loss from urea by a minimum of 50% over a time period of one week.
A further object was to arrive at a urea fertilizer having low ammonia loss when applied either in the form of solid fertilizer or of liquid fertilizer, especially urea-ammonium nitrate (UAN) solutions. Having thoroughly studied known urease inhibitors and their various effects, the inventors decided to investigate further application of metal nitrates. Though the anion is considered largely unimportant, nitrates were chosen in view of their agronomic value. Sulphate anions were found to be effective, but less so than nitrate and chlorides were found to behave similarly to nitrates.
It is known that hydrated salts form complexes when mixed with urea. The reaction is one in which the water of crystallisation is replaced. Contrary to that taught in the above referred application, the inventors in their search for new salts as urease inhibitors found during their tests that the effect of nitrates of metals of variable valency state were quite promising. Various such nitrates were tested and the effects of iron nitrates were found to be most effective. Further investigations showed that ferric nitrate gave the best results while ferrous nitrates were excluded from further tests. Aluminium nitrates were also found to give excellent results, almost similar to those obtained for ferric nitrates. Accordingly, those two most promising salts were subjected to further tests, both pot and field tests.
Hydrated ferric nitrate forms complexes with urea according to the following formula:
Fe(NO3)3.9H2O + 6 H2NCONH2 ■» Fe(NO3)3.6 H2NCOH2 + 9H2O
(The ratio of ferric nitrate to urea may vary.)
The solid products were obtained by drying the mixture and are chemical compounds in their own right. Excess urea could be present, that is, not bound to the original iron nitrate-urea complex. The free urea would be evenly distributed throughout the mixture of urea and the complex. Several mixtures of the said complex with and without excess urea were prepared and tested with regard to loss of ammonia and plant scorch. Similar complexes were formed between aluminium nitrate and urea and various mixtures containing excess urea were also prepared for testing. The results from these tests showed the mean absolute loss of ammonia from urea to be 33.5% compared to 2.1% from ammonium nitrate. The performance of the ferric nitrate/urea system seemed to be dependent of Fe'". It was found that for the pure complex and for the complex with 3 or 6 mole free urea per complex only about 50-60% of added urea had been hydrolyzed. The effect of a ferric nitrate/urea system depends on the level Fe'", but reduction of ammonia loss from urea was obtained even with low ratios of ferric nitrate. The preferred molar ratio ferric nitrate : urea was found to be in the range 1:1 to 1:15. Similar results were found for the aluminium nitrate/urea system though the effect was slightly lower. The preferred molar ratio aluminium nitrate : urea was found to be 1:1 to 1:18.
Ferric nitrate usually will be the preferred additive. However, depending on the soil on which the fertilizer is to be applied, aluminium nitrate might be preferred.
When ferric nitrate was mixed with UAN solutions, no precipitation was observed. Accordingly, decomposition as taught by the above referred WO-patent application did not take place.
The scope of the invention and its specific features are as defined by the attached claims.
The invention will now be further explained in the following examples.
Example 1
This example describes ammonia loss from soil with surface applied fertilizers. Ammonia losses relative to urea were investigated for 10 cations and one anion (borate). The tests were performed in 12 pairs of glass jars containing fresh soil which was light sandy loam. Prior to the tests the moisture content of the soil was adjusted to about 10%. Nitrogenous fertilizers, urea, ammonium nitrate or a metal salt-urea complex of known analysis were added to provide 0.149 mg N, which corresponds to approximately 175 kg ha-1 on a surface basis. Released ammonia was collected in bottles containing standardized acid whereby the ammonia loss could be calculated by standard methods. The tests were performed at about 20°C and were carried out over a period of 6 days. Nitrates were chosen as anions except for copper where this was not possible. The metal nitrates were added as solids to urea prior to particulation. The metal : urea ratio was fixed at 1:6 for all the metal salt-urea complexes.
It is emphasized that some of the metals, primarily copper, zinc and nickel were applied in amounts that would be deemed toxic for normal agricultural use.
Several of the tested metal salt-urea complexes were found to reduce ammonia loss, but none appeared to be as effective as the ferric nitrate-urea complex. The aluminium nitrate-urea complex gave slightly lower effect. The effects, given as ammonia loss relative to urea = 100 for the various fertilizers, are shown in fig 1.
Example 2
This example shows the ammonia loss relative to urea = 100 for fertilizers consisting of 1 mole urea and 1 mole Fe(NO3)3 or 1 mole urea and 1 mole CuSO4, respectively. The experiments were performed as described in example 1. The results are shown as function of time(days) in fig. 2. As can be seen from this figure, the effects for the iron complex were substantially greater than for the copper complex.
Example 3
This example shows the effect of iron-urea complexes containing none or some free urea. The results are compared to those obtained for ammonium nitrate and urea as function of time (days). The effect is stated as % N lost as ammonia, cumulative. The results are shown in fig. 3. As can be seen from this figure, the best results were obtained when no free urea was present ("Fe2"), but even with 3 moles free urea for each ferric nitrate-urea complex ("Fe6") the results are excellent, especially for the first 7 days. The results also show that the metal needs not to be bound to urea to be effective. Further tests showed that even with relatively low contents of ferric/aluminium nitrate in the urea fertilizer the reduction in ammonia losses was substantial compared to conventional urease inhibitors.
The new fertilizers according to the invention were also tested with regard to phytotoxicity. Three alkaline soils were used, two of which had high free lime contents. Assessment was made by con-secutive emergent plant counts over a period. Three ratios of urea with ferric nitrate and one of urea with aluminium nitrate were examined. Urea had a highly depressive effect on plant emergence which was overcome equally by all the metal salt ratios tested giving effects similar to that of ammonium nitrate.
Investigations were also carried out to study possible build-up of metal salt in the soil. Two acid and one highly alkaline soils were used in these tests. There was no indication in any of the three soils of reduction in dry matter yield from the fertilizer according to the invention compared to ammonium nitrate. There was no evidence from these tests of a risk of toxicity build-up from repeated application of metal salts when fertilizers according to the invention were applied under practical conditions.
As shown above the inventors succeeded in arriving at new urea- containing fertilizers having substantially reduced ammonia loss due to urease induced hydrolysis. Application of these new fertilizers was also found to give very low plant scorch compared to known urea and urea-containing fertilizers.

Claims

Claims
1. Urea-containing fertilizer containing at least one urease inhibitor comprising metal nitrate, characterized in that the fertilizer contains ferric nitrate and/or aluminium nitrate-urea complexes or the fertilizer contains both ferric nitrate and urea and urea or aluminium nitrate and urea.
2. Urea-containing fertilizer according to claim 1 , characterized in that the fertilizer contains a ferric nitrate-urea complex.
■
3. Urea-containing fertilizer according to claim 1, c aracterized in that the fertilizer is a liquid urea-ammonium nitrate solution or slurry.
4. Urea-containing fertilizer according to claim 1, characterized in that the molar ratio ferric nitrate-urea complex : urea is in the range of 1:1 to 1:15.
5. Urea-containing fertilizer according to claim 1, characterized in that the molar ratio aluminium nitrate-urea complex : urea is in the range of 1:1 to 1:18.
6. Urea-containing fertilizer according to claim 1, characterized in that the molar ratio ferric nitrate-urea complex : urea is 1:4-6.
PCT/NO1994/000212 1993-12-30 1994-12-23 Urea-containing fertilizer WO1995018081A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU14274/95A AU1427495A (en) 1993-12-30 1994-12-23 Urea-containing fertilizer

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9326538.7 1993-12-30
GB9326538A GB2285803A (en) 1993-12-30 1993-12-30 Urea - containing fertilizer

Publications (1)

Publication Number Publication Date
WO1995018081A1 true WO1995018081A1 (en) 1995-07-06

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WO (1) WO1995018081A1 (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1064943C (en) * 1997-03-28 2001-04-25 寇庆德 Urea synergist
WO2011102815A1 (en) * 2010-02-19 2011-08-25 Mazilnikov Gennadiy Vasilevich Use of aluminium nitrate as a nitrogen action intensifier and as a systemic activator of morphogenetic plant processes, and fertilizer on the basis thereof
WO2014033161A2 (en) * 2012-08-29 2014-03-06 Yara International Asa Method for limiting the use of an ammonium nitrate fertilizer as a precursor for an explosive and composition therefor
US10501383B2 (en) 2014-10-31 2019-12-10 Koch Agronomic Services, Llc Nitrification inhibitor compositions and methods of making thereof

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7494525B2 (en) 2005-02-22 2009-02-24 Tessenderlo Kerley, Inc. Calcium polysulfide, potassium polysulfide, calcium thiosulfate, and magnesium thiosulfate as urease inhibitors
WO2019204163A1 (en) 2018-04-20 2019-10-24 Tessenderlo Kerley, Inc. Liquid nitrogen fertilizer compositions and additives therefore
EP3575278A1 (en) 2018-05-31 2019-12-04 Tessenderlo Kerley, Inc. Liquid nitrogen fertilizer compositions and additives therefor

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2855036A1 (en) * 1977-12-22 1979-07-05 Fisons Ltd NEW COMPOSITIONS AND METHOD FOR THE PRODUCTION AND USE THEREOF
WO1990011262A1 (en) * 1989-03-18 1990-10-04 Stoller Chemical Limited Stabilized urea based fertilizers for foliar application

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE754561A (en) * 1969-08-09 1971-02-08 Badishe Anilin & Soda Fabrik DOUBLE CALCIUM NITRATE AND UREA SALT SUITABLE FOR GRANULAR SPREADING AND STORAGE
CN85102658A (en) * 1985-04-01 1986-09-24 四川大学 The synthetic method of complexing fertilizer iron hexaurea trinitrate (3)
JPH062628B2 (en) * 1986-07-22 1994-01-12 宇部興産株式会社 Granular fertilizer containing slow-release nitrogen fertilizer

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2855036A1 (en) * 1977-12-22 1979-07-05 Fisons Ltd NEW COMPOSITIONS AND METHOD FOR THE PRODUCTION AND USE THEREOF
WO1990011262A1 (en) * 1989-03-18 1990-10-04 Stoller Chemical Limited Stabilized urea based fertilizers for foliar application

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1064943C (en) * 1997-03-28 2001-04-25 寇庆德 Urea synergist
WO2011102815A1 (en) * 2010-02-19 2011-08-25 Mazilnikov Gennadiy Vasilevich Use of aluminium nitrate as a nitrogen action intensifier and as a systemic activator of morphogenetic plant processes, and fertilizer on the basis thereof
WO2014033161A2 (en) * 2012-08-29 2014-03-06 Yara International Asa Method for limiting the use of an ammonium nitrate fertilizer as a precursor for an explosive and composition therefor
WO2014033161A3 (en) * 2012-08-29 2014-08-07 Yara International Asa Method for limiting the use of an ammonium nitrate fertilizer as a precursor for an explosive and composition therefor
US9328031B2 (en) 2012-08-29 2016-05-03 Yara International Asa Method for limiting the use of an ammonium nitrate fertilizer as a precursor for an explosive and composition therefor
US10501383B2 (en) 2014-10-31 2019-12-10 Koch Agronomic Services, Llc Nitrification inhibitor compositions and methods of making thereof

Also Published As

Publication number Publication date
GB9326538D0 (en) 1994-03-02
AU1427495A (en) 1995-07-17
GB2285803A (en) 1995-07-26

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