ISSN:
1432-0789
Keywords:
Peat
;
Reseed
;
Nitrogen mineralization
;
Ammonifiers
;
Nitrogen immobilization
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Geosciences
,
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Summary Mineral-N dynamics have been measured over a period of 3 years in PK- and NPK-treated plots (4 m2) laid out on an area of poorly drained, reseeded, blanket peat in the north of Scotland. Mineral-N, present in the peat almost entirely as NH in4 sup+ , accumulated in winter, reaching 42 kg N ha−1 in the surface 10 cm in April before the application of 112.5 kg N ha−1 as NH4NO3 or urea. In situ incubation of peat cores isolated to prevent leaching, and with grass tops removed, confirmed that net mineralization occurred between November and April, with the greatest rate, 1.2 kg N ha−1 day−1, recorded between March and April. During the period May to early June, immobilization of N predominated and rates of net immobilization ranged between 0.2 and 0.8 kg N ha−1 day−1. This coincided with a poor uptake into herbage, less than 16% of soil mineral N and fertilizer NH4NO3 in June of the first 2 years. The largest counts (most probable number) of ammonifying bacteria in the surface 5 cm were recorded in July for aerobes (27.1×109 litre−1) and August for anaerorbes (7.1×109 litre−1). N fertilizer increased these counts significantly (P〈0.05) to 56×109 aerobes and 13×109 anaerobes. During July and August, in 2 out of the 3 years, mineralization predominated over immobilization and mean net rates of up to 0.9 kg N ha−1 were recorded.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00337342
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