Ammonia Volatilization from Liquid Digested Sewage Sludge as Affected by Placement in Soil1
- F. J. Adamsen and
- B. R. Sabey2
In a laboratory study, liquid sewage sludge was added to an Olney sandy loam (fine-loamy, mixed, mesic, Ustollic Haplargids) at a rate equivalent to 7.6 Mg ha−1 either on the surface or 25 mm below the surface. The sludge contained 11.2 g kg−1 NH4-N and 21.6 g kg−1 organic-N on a dry weight basis and 27 g L−1 solids. Surface applied sludge lost 40.3% of its NH4-N as NH3 in the first 2 weeks (95% of the total loss) while subsurface applied sludge lost 0.35% of added NH4-N as NH3 in the same period. Total NH3-N loss from surface applied liquid sludge was 36.0 kg ha−1, which was 42.4% of added NH4-N. Soil analyses at the end of the study showed that 96% of the inorganic-N was in the form of NO3 in sludge amended treatments. Fertilizer value of liquid sludge will be greater with subsurface injection than surface application. Where available N limits sludge loading rates surface application would reduce land requirements.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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