Ammonium hydrogensulphite

Toxicity to soil microorganisms

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to soil microorganisms

Data waiving:

other justification

Justification for data waiving:

other:

Reference 2

Endpoint:

toxicity to soil microorganisms

Type of information:

experimental study

Remarks:

field study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

no guideline followed

Principles of method if other than guideline:

The authors conducte a 3 year field study and examined the effect of a single ammonium sulphate application on the abundance of nitrogen fixing bacteria in a spanish rice field.

Cyanobacterial population in the soil was measured in cores collected from each plot, at 4–5-weekly intervals throughout the growth cycles, as previously described (Quesada and Fernández Valiente, 1996). Likewise, ‘in situ’ assays of nitrogenase activity (ARA) (Quesada et al., 1989) were performed in four sampling periods, May, June, July and September, every year . At each sampling period, three assay chambers were placed in each plot.

GLP compliance:

no

Specific details on test material used for the study:

No further details on test material provided.

Analytical monitoring:

no

Vehicle:

no

Details on preparation and application of test substrate:

Not specified.

Test organisms (inoculum):

soil

Total exposure duration:

36 mo

Remarks:

three consecutive crop seasons

Test temperature:

Ambient.

Moisture:

Flooded Rice fields.

Details on test conditions:

The rice fields studied are located in the Eastern Iberian Peninsula, surrounding the coastal lagoon of ‘La Albufera’ near Valencia. Spain.

Nominal and measured concentrations:

0, 17.5, 35, 70, 140 kg N/ha, corresponding to 0, 22.5, 45.1, 90.1, 180.3 kg NH4/ha

Reference substance (positive control):

no

Key result

Remarks on result:

other: Applied ammonium sulfate at 17.5, 35, 70, and 140 kg N/ha reduced the abundance of cyanobacteria and the determined nitrogen fixation.

Remarks:

Ammonium sulfate treatments of up to 70 kg N/ha caused a moderate increase in grain yield, without severely affecting the N2 fixing ability (less than 50% reduction) or cyanobacteria abundance.

Details on results:

A significant negative correlation (r= -0.53; p < 0.05; n= 35) between the abundance of N2-fixing cyanobacteria and amount of N fertilizer applied was observed
Nitrogenase activity decreased linearly as the amount of N fertilizer increased. A significant negative correlation (r= -0.90; p < 0.05; n= 60) between acetylene reducing activity and the amount of N fertilizer was observed. The inhibition was only partial and differences among treatments were only significant (one-way analysis of variance) in two years (1990, 1991).

Reported statistics and error estimates:

Correlation analysis.

Validity criteria fulfilled:

not applicable

Remarks:

field study

Conclusions:

In a 3-year field study in spanish rice fields, applied ammonium sulfate at 17.5, 35, 70, and 140 kg N/ha reduced the abundance of cyanobacteria and the determined nitrogen fixation, whereas ammonium sulfate treatments of up to 70 kg N/ha caused a moderate increase in grain yield, without showing sever effects on the N2 fixing ability (less than 50% reduction) or cyanobacteria abundance.