ISSN:
1573-5036
Keywords:
ammonia toxicity
;
chloride
;
inhibition
;
nitrate
;
nitrification
;
salt stress
;
urine
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Abstract The effects of urinary chloride and nitrogen concentration and osmotic pressure on the nitrification of ammonium in a calcareous soil treated with cow urine were examined. Urinary chloride concentrations of up to 7.4 g L−1 had no effect on the rate of nitrification, as determined by the accumulation of soil nitrate. Osmotic stress, generated using a mixed salt solution, had an inhibitory effect on nitrification at soil osmotic pressures lower than or equal to −1.0 PMa. Nitrification was completely inhibited at a soil osmotic pressure of −2.6 MPa. Accumulation of nitrate after a lag phase of 18 days was noted in the −2.0 MPa soil osmotic pressure treatment, indicating some degree of adaptation or osmo-regulation within the nitrifying population at this stress level. High urine-N concentrations resulted in considerable nitrite accumulations and reduced nitrification activity through the effect of free ammonia. It is concluded that in most temperate grassland soils at near-neutral pH, urinary chloride and nitrogen are unlikely to reduce nitrification rates, except where urine-N concentrations exceed 16 g N L−1. Inhibition due to osmotic stress will be directly related to soil moisture status and may be particularly severe in dry, light-textured soils.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00009124
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