Potassium sulfate

Toxicity to terrestrial plants

Administrative data

Endpoint:

toxicity to terrestrial plants: long-term

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

1993 - 1995

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

other: Limited information provided.

Data source

Reference

Reference Type:

publication

Title:

Cotton response to the rate and source of sulfur on a sandy coastal plain soil.

Author:

Mullins, G.L

Year:

1998

Bibliographic source:

Journal of Production Agriculture 11(1):214-218

Materials and methods

Test guideline

Guideline:

other: not mentioned

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Potassium sulfate (K2SO4)

IUPAC Name:

Potassium sulfate (K2SO4)

Details on test material:

Potassium sulfate (K2SO4)

Sampling and analysis

Analytical monitoring:

not specified

Details on sampling:

no data

Test substrate

Vehicle:

not specified

Details on preparation and application of test substrate:

no data

Test organisms

Species:

other: Cotton plant

Plant group:

Dicotyledonae (dicots)

Details on test organisms:

Cotton plant

Study design

Study type:

field study

Total exposure duration:

24 mo

Test conditions

Details on test conditions:

A field study using cotton was conducted on a Lucy loamy sand from 1993 to 1995. Sources of applied sulfur were ammonium sulfate, elemental S, potassium sulfate, potassium magnesium sulfate, and potassium thiosulfate. Rates of applied S were 0, 10, 20, and 40 lb/acre. All sources at each rate were preplant broadcast applications. All treatments received total annual applications of 90 lb N/acre, 60 lb PO5/acre, and 140 lb K2O/acre. Upper-most mature cotton leaves were collected at early bloom for S analysis. Seed cotton yields were determined at maturity by machine harvesting the two center rows from each plot. Fiber properties evaluated included micronaire, length, length uniformity, strength, elongation, trash uniformity, and color. Prior to testing, soil samples were taken to determine background levels of extractable S.

Results and discussion

Details on results:

Lint yields were increased by the rate of S, but were not affected by the source of S, the time of S application, or the interaction between source and rate. Applying 20 lb S/acre increased lint yields by an average of 15 to 26% depending on the year. A linear response to S rate in 1994 was attributed to the high rainfall received in July and a probably leaching of some of the applied S in this sandy soil. The quadratic responses observed in 1993 and 1995 were probably attributed to drought conditions. Potassium sulfate produced slightly lower yields than ammonium sulfate and potassium magnesium sulfate. In 1995, fiber length was increased slightly the application of S. Fiber length was also affected by the interaction between source and rate, but there were no consistent differences among sources across rates. Concentration of S in cotton leaves collected at mid-bloom increased with the rate of applied S during the study. In 1994 and 1995, there was a significant interaction between rate and time of application for S concentration in leaves. Sulfur applications at early squaring resulted in higher S concentrations than preplant treatments.

Applicant's summary and conclusion

Conclusions:

Potassium sulfate produced slightly lower yields than ammonium sulfate and potassium magnesium sulfate.