Microbial Response to Sodic Soil Amendments: Flue-Gas Gypsum, By-Product Lime, and Langbeinite

ABSTRACT

Amendments are commonly applied to soil to ameliorate sodic conditions, but their effect on improving microbial activity depends on the severity of sodicity and the types and rates of amendments applied. Changes in metabolic activity in response to three chemical amendments (flue-gas gypsum (FG), spent lime, and langbeinite) applied at three rates to two sodic soils were measured using infrared gas analyzer during 76 days of incubation. Spent lime had the greatest influence on microbial activity at rates of 33.6 and 67.2 Mg ha⁻¹, and at the highest rate of application (67.2 Mg ha⁻¹) cumulative respiration was over two times greater than the control for both soils. High rates of langbeinite yielded the lowest respiration but were not significantly different than the control and the FG had no significant influence on respiration. The use of spent lime increased microbial activity which, in turn, may improve soil health through increased microbial activity.

KEYWORDS:

• Problem soils
• respiration
• soil improvement
• gypsum
• lime
• langbeinite

Acknowledgments

We would like to thank research technician, Kevin Horsager, and undergraduate student, Rachel Leitch, for all of their assistance. Funding for this project was provided by the North Dakota Soybean Council.

Additional information

Funding

This work was supported by the North Dakota Soybean Council.