Immobilization and Mineralization Rates of Nitrogen during Decomposition of Plant Residues in Soil1
- B. J. Stojanovic and
- F. E. Broadbent2
Two well drained New York soils of the Gray-Brown Podzolic group, Ontario loam and Honeoye silt loam, were incubated under controlled temperature, moisture, and aeration. Soils were treated with either wheat straw or corn leaves, and inorganic nitrogen (ammonia or nitrate). Samples were taken at 2, 4, 6, 10 and 18-day intervals. Ammonia and nitrate nitrogen were determined. Enriched nitrogen was employed for computing mineralization and immobilization rates.
Recovery data indicate that rapid immobilization took place when wheat straw was added in combination with either ammonia or nitrate nitrogen. Immobilization of added ammonia occurred when corn leaves were added with ammonia nitrogen. Reduction of nitrate was negligible in treatments where corn leaves plus nitrate nitrogen were added.
Mineralization and immobilization data indicate that a substantial amount of nitrogen is turned over in the presence of available energy material. It has been further observed that immobilization is of significant magnitude even in the decomposition of a high nitrogen-containing material such as corn leaves. For example, in the case of wheat straw plus nitrate, during the 2 to 6-day interval, the equivalent of 56 pounds of nitrogen per acre per day was immobilized. Maximum turn over occurred in the 0 to 2-day interval with corn leaves. In the latter case the maximum microbial activity would be attained earlier since the energy material was more available.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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