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This article in SSSAJ

  1. Vol. 75 No. 4, p. 1574-1577
    Received: Nov 11, 2010

    * Corresponding author(s): usingh@ifdc.org
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Separating Nitrogen Polymers from Urea in Ureaform Fertilizer to Study Soil Nitrogen Transformations

  1. S. H. Chiena,
  2. U. Singh *b,
  3. E. R. Austinb and
  4. J. S. Krusec
  1. a International Fertilizer Development Center (retired) Muscle Shoals, AL 35662 currently at 1905 Beechwood Circle Florence, AL 35630
    b Research and Development Division International Fertilizer Development Center Muscle Shoals, AL 35662
    c Georgia-Pacific Corp. 2883 Miller Road Decatur, GA 30035


A technique was developed to separate polymers from urea in a soluble urea-formaldehyde (ureaform) N fertilizer that contained 45.3% of total N as urea N and 54.0% as polymer N. First, urease was used to hydrolyze urea to NH4HCO3. Then NH4–N was precipitated with sodium tetraphenylboron followed by filtration. The filtrate that contained the polymers was compared with urea and ureaform in a soil incubation at 0, 1, 2, 3, 5, 8, 10, and 12 wk. The N rates of urea and polymers applied separately were the same as urea and polymers applied from ureaform. The results showed that the amounts of NH4–N and NO3–N produced from the ureaform fertilizer were about the same as the sum of those from urea and polymers, indicating the successful separation of polymers from the urea in the ureaform fertilizer. Mineralization of polymer N to NH4–N and NO3–N ranged from 45 to 80% of the polymer N applied during the incubation.

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