Registration Dossier

Diss Factsheets

Ecotoxicological information

Toxicity to soil microorganisms

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

Studies of the effects of ammonium sulfate on three nitrogen-fixing soilbacteria and on total soil bacteria have been carried out. Theabundance of nitrogen-fixing cyanobacteria in a Spanish rice field wasreduced significantly following a single ammonium sulfate applicationeven at the lowest application of 82.5 kg/ha (calculated from 17.5 kgN/ha) (Fernández Valiente et al., 2000). In another experiment,biological nitrogen-fixing ability in a field under crop rotation insouthern Sweden was reduced (nitrogen-fixing legume bacteria) oreliminated (nitrogen-fixing blue green algae) by over thirty years annualapplication of 377 kg/ha ammonium sulfate (calculated from 80 kg N/ha)(Martensson and Witter, 1990). The lowering of soil pH by ammoniumsulfate was the main cause of the reduction in the nitrogen-fixingcapacity of the soil. In this experimental field, total soil biomass was reduced by almost 50 % relative to unfertilized control plots (Witter,Martensson and Garcia, 1993), although base respiration rate was unaffected.


Nitrogen fixation and total soil biomass (but not soil baserespiration rate) can be affected by ammonium sulfate applied at 82.5kg/ha or more.

Key value for chemical safety assessment

Additional information