ISSN:
1573-5036
Keywords:
Acetylene inhibition technique
;
Denitrifier counts
;
Dinitrogen
;
Nitrous oxide
;
Potential denitrification rates
;
15N balance sheet
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Summary Field studies were conducted over a period of two years (April to November inclusive) to assess gaseous losses of nitrogen (N2O+N2) using the acetylene inhibition technique from two Black Chernozemic soils (Hoey cl and Hamlin cl) under continuous wheat (W-W) and wheat-summerfallow (W-F) rotations. Gaseous N losses from cropped fields were very low in both years ranging from 2 to 3 kg N.ha−1.yr−1; up to 60% of this nitrogen was generally lost during the early spring period (April to May). Losses of N from the W-F rotation were two to five times higher than from the continuous wheat rotation. The contribution of lower soil horizons towards gaseous N losses was negligible; the marked decrease in N2O flux with soil depth followed similar decreasing patterns of organic carbon, denitrifier counts and potential denitrification rates. 15N-labelled balance studies were carried out on microplots established on the same two sites during the 1981 growing season. Cumulative nitrogen losses measured during the period May 26 to August 31 using the acetylene technique were 1.8±0.7 and 1.2±0.3 kg N.ha−1 at the Hoey and Hamlin sites, respectively. These results agree closely with the amount of nitrogen which could not be accounted for in the N balance studies (2.3±3.1 and 1.2±2.1 kg N.ha−1, respectively). While the acetylene technique is highly labour intensive, these studies indicate it has an advantage over the15N balance approach, namely, the capability to assess short-term response of denitrification to rainfall events in particular.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02178610
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