ISSN:
1573-5036
Keywords:
Autotrophic
;
Heterotrophic
;
Perfusion
;
Soil nitrification
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Summary A new perfusion system for the rapid and simple measurement and characterization of potential rates of soil nitrification is presented. The system involved pumping a buffered NH 4 + solution, containing chlorate to block oxidation of NO 2 − to NO 3 t- sole product of nitrification), through a soil column. Perfusate was then passed through a cation exchange resin to remove remaining NH 4 + (preventing further nitrification), and through a sephadex gel to control the perfusion rate. Determinations of NO 2 − eluting from the column enabled rates of nitrification to be calculated. Soil samples were also perfused with C2H2 (1%) in the perfusing solution, as a partition of autotrophic and heterotrophic nitrification. In an agricultural soil adjusted to a range of pH values (then maintained at constant pH over 25 years), potential rates of nitrification (using unbuffered perfusate) decreased with increasing soil acidity, while at each pH almost all nitrification was blocked by C2H2. This suggested autotrophs dominate nitrification in agricultural soil, regardless of acidity. In an acid coniferous soil, however, 90% of potential nitrification was unaffected by C2H2, suggesting heterotrophic nitrification is of particular significance in acid forest soils.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02374949
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