How salty is too salty?
Working in the Agroecology lab has allowed me to expand my laboratory skills well as my knowledge of our complex and interconnected ecosystems. The project I am involved in is studying the effects of saltwater intrusion on agricultural fields and the potential of certain plant species to remediate salty soils. To contribute to this research, I have been grinding soils collected from experimental sites and processing them to measure the electrical conductivity of the soils. Electrical conductivity is utilized as a method to understand the number of dissolved salts (solute concentration) in the soils being studied [1]. This is important to know because soil salinity directly affects plant productivity and soil health. Increased soil salinity will also force farmers to change their field management practices which can be costly and time consuming.
Multi-parameter probe used for measuring electrical conductivity in soils.
This research is paramount to understanding how agroecosystems systems may be affected by factors brought about by climate change. When looking at the current drivers of saltwater intrusion; sea level rise, storms and tides, droughts, water management strategies, and land-water connectivity [2], three out of these five factors will be magnified by climate change in the future. As climate change intensifies it will hasten the rise of sea levels, storm intensity and frequency, and elevate temperatures. These environmental changes will increase stress on crops that are not adapted to wet, salty soils, threatening our global food supplies.
By testing the electrical conductance of soils, we can “track” the salinity level of our experimental plots. These plots hold two experimental plant species and a control. For the control plant species Digitaria sanguinalis, a common weed, will be compared against a remediation species, Spartina patens (saltmarsh hay) and a salt tolerant species, Panicum virgatum (switchgrass). By studying the experimental plots over the past 4 years (2018-2021) it is possible to see fluctuations in salinity over the span of years, as well as compare the levels of soil salinity in the experimental and control plots from the four farm sites.
References
1. Shmulik P. F. (2005) Soil properties influencing apparent electrical conductivity: a review, Computers and Electronics in Agriculture, Volume 46, Issues 1–3, pp 45-70, ISSN 0168-1699, https://doi.org/10.1016/j.compag.2004.11.001.
2. Tully K. et al. (2019) The Invisible Flood: The Chemistry, Ecology, and Social Implications of Coastal Saltwater Intrusion, BioScience, Volume 69, Issue 5, pp 368–378, https://doi.org/10.1093/biosci/biz027.