About Us | Help Videos | Contact Us | Subscriptions

Soil Science Society of America Journal Abstract - Division S-3—Soil Biology & Biochemistry

Microbial Nitrogen Transformations in Response to Treated Dairy Waste in Agricultural Soils


This article in SSSAJ

  1. Vol. 68 No. 6, p. 1867-1874
    Received: June 18, 2003

    * Corresponding author(s): wei_shi@ncsu.edu
Request Permissions

  1. Wei Shi *a,
  2. Bruce E. Millerb,
  3. John M. Starkb and
  4. Jeanette M. Nortonb
  1. a Dep. of Soil Science, North Carolina State Univ., Raleigh, NC 27695
    b Dep. of Plants, Soils, and Biometeorology, Utah State Univ., Logan, UT 84322


Dairy wastes are commonly applied to croplands as N fertilizers, but the dynamics of N release and transformations during the growing season are difficult to predict. We compared N mineralization kinetics and examined microbial N transformations in soil receiving dairy-waste compost vs. lagoon effluent. Mineralization kinetics was examined with a 70-d laboratory incubation, and a first-order model was used to derive mineralization parameters. Measurements of N transformations were conducted with 15N pool dilution techniques in silage corn field plots that were unfertilized or fertilized with ammonium sulfate, lagoon effluent, or compost at two rates equivalent to 100 or 200 kg available N ha−1 The N mineralization potential was higher and the first-order rate constant was lower in soil receiving compost than lagoon effluent. Approximately 6% of compost N was mineralized within 2.5 mo; in contrast, up to 90% lagoon effluent organic N was released. However, silage yield was greatest in the compost treatment, showing that synchronization of N availability is as important as the amount mineralized. The field 15N measurements indicated that microbial NO 3 consumption was negligible despite the treatments. Microbial NH+ 4 immobilization in soil receiving dairy wastes was similar to that in soil unfertilized or fertilized with inorganic N. Soil treated with the high-rate compost had the highest rates of mineralization and nitrification, which led to the highest soil NO 3 accumulation. Our observations suggest that peak plant demand is met by the compost N; however, its high N mineralization potential makes the management of dairy compost a difficult task.

  Please view the pdf by using the Full Text (PDF) link under 'View' to the left.

Copyright © 2004. Soil Science SocietySoil Science Society of America