ISSN:
1432-0789
Keywords:
Key words Dry biomass production
;
Maize
;
15N isotope
;
Nitrite toxicity
;
Nitrogen recovery
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Geosciences
,
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Abstract When comparing nitrite (NO2 –) and nitrate (NO3 –) toxicity to maize (Zea mays L.) growth, it is important to know the fate of applied nitrogen (N). A pot experiment, using potassium nitrite (K15NO2) and potassium nitrate (K15NO3) was conducted to determine the fate of N (0, 75, 150, and 225 mg N kg–1 soil) applied to a sandy loam soil collected from Gistel (Belgium). The total dry weight of the plants treated with NO2 – was lower than that of the plants treated with NO3 – at 15 and 26 days after N application (harvest 1 and harvest 2, respectively). Shoot and root biomass reduction started at a relatively low NO2 – application rate (75 mg NO2 –-N kg–1). Biomass reduction increased, at both harvests with increasing amounts of NO2 – to more than 55% at the highest application rate (225 mg NO3 –-N kg–1). In the NO3 – treatment, a reduction of 16% in total plant dry biomass was recorded only at the highest application rate (225 mg NO2 –-N kg–1), at both harvest times. The 15N plant uptake (shoots plus roots) at harvest 1 decreased with increasing N application rates of both N forms (KNO2 and KNO3). Twenty-six days after the N application, the total 15N taken up by the plant increased in all treatments in comparison with 15 days after the N application. However, only at higher rates of N application (150 and 225 mg N kg–1) was the 15N uptake by the NO2 – fed plants significantly lower than by the NO3 – fed plants. The percentage of immobilized N from the applied N was low (0–17.7%) at both harvests, irrespective of the N source. However, with relatively low N application rates (75 mg N kg–1), the immobilized N in the soil decreased with time. This may be due to the re-mineralization of the applied N. The percentage of inorganic 15N in the soil in NO2 – treatments was slightly lower than in equivalent doses of NO3 –. This might be due to higher losses of N as N-oxides. Unaccounted for N from the applied N ranged from 21% to 52% for the NO2 – treatments and from 3% to 38% for the NO3 – treatments.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s003740050422
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