ISSN:
1573-5036
Keywords:
denitrification
;
mineralization
;
N-cycling
;
rice soils
;
stable N isotopes
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Abstract Nitrification and denitrification rates were estimated simultaneously in soil-floodwater columns of a Crowley silt loam (Typic Albaqualfs) rice soil by an15N isotopic dilution technique. Labeled NO 3 − was added to the floodwater of soil-water columns, half were treated with urea fertilizer. The (NO 3 − +NO 2 − )−N and (NO 3 − +NO 2 − )−N concentrations in the floodwater were measured over time and production and reduction rates for NO 3 − calculated. Nitrate reduction in the urea amended columns averaged 515 μmol N m−2h−1 and nitrification averaged 395 μmol N m−2h−1 over the 35–153 d incubation. The nitrification rate for 4–19 d sampling period (1,560 μmol N m−2h−1) in the urea amended columns was almost 9 times greater than the reduction rate (175 μmol N m−2h−1) over the same period. Without the addition of urea the NO 3 − production rate averaged 32 μmol N m−2h−1 and reduction 101 μmol N m−2h−1.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02182050
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