Ammonia Volatilization from Ratios of Formamide and Urea Solutions in Soils1
- J. R. Loftis and
- C. E. Scarsbrook2
Ammonia volatilization from soils treated in the surface 1½ cm with mixtures of formamide and urea (F:U) was measured in laboratory incubation experiments. Norfolk sandy loam, which had a cation exchange capacity (CEC) of 3.7 meq/100 g and an initial pH of 5.9, evolved 18.5% at the highest rate of applied N. Losses of N from Boswell fine sandy loam, which had a CEC of 13 meq/100 g and an initial pH of 5.8, was 13.0%. Sumter clay, which had a CEC of 33 mg/100 g and an initial pH of 7.8, gave negligible losses. Urea was nitrified at approximately twice the rate of formamide in Sumter clay, but rates were low and similar in Norfolk and Boswell soils. There was a larger percentage loss of NH3 at the high N rates than at the lower rates. Addition of Ca(OH)2 increased losses of NH3 on Norfolk soil. All ratios increased the soil pH alike and the rate of application determined the magnitude of the increase. Increasing the F:U generally had no effect on NH3 losses. The results showed a large positive relationship between NH3 loss and the final soil pH of Norfolk, but the effect was smaller on Boswell.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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