A logistical circus
Barley seed germinating at 10 different osmotic potentials in an incubator at the George Washington University.
I have officially been a M.S student for one year and what a ride it has been! It was likely 6 months into the program by the time my project was fully formed, I had my first committee meeting, and I was running between three different places to conduct my research. I study the effects of saltwater intrusion on agroecosystems on the lower eastern shore of Maryland. My objective is to provide information to help farmers who are affected by saltwater intrusion make management decisions that benefit both their farm and the environment, through understanding how different crops survive saltwater intrusion and how carbon is stored in soil.
Salt-tolerant soybean beginning to grow on a salt-intruded farm field.
Although this is my first post, a number of interns have already talked about my research. Karla Rosales Lobos talked about preparing treatment plots that were planted with various crop species, as well as quantifying the percent cover of each species in the plots. This work was in relation to understanding how different crops survive during saltwater intrusion, which has been revamped thanks to the NIFA grant (NIFA grant number) and the team of scientists I work with. This has allowed us to design a randomized block treatment to study alternative crop rotations that include salt-tolerant soy, barley, rapeseed, sorghum, switchgrass, and Spartina patens on four different farm fields on the lower eastern shore. Jonathan Moy and Anna Collishaw talked about “Soils Camp”, which I ran this spring as my big field campaign to collect soils along a salinity transect, down to a depth of 140 cm, on 6 saltwater intruded farm fields (a total of 257 soil samples!). Jonathan spent his spring semester working with me processing all of our soil samples to understand if carbon storage is chemically changed due to saltwater intrusion.
We followed the Six et al. (2000) method to separate soil aggregates into 5 different size classes (large macroaggregate, small macroaggregate, floating particulate organic matter, microaggregate, and silt and clay). This information will help us in understanding whether carbon is in a more active pool and easily accessible by plants and microbes, or if carbon is in a passive pool and stored long-term.
As all of this work has been going on, I have also been running an experiment at George Washington University with Dr. Keryn Gedan to understand the germination rate of crop species, agricultural weed species, and restoration species at different osmotic potentials. Osmotic potential is attributable to the presence of ions and other solutes in water (Weil and Brady, 2016). As water molecules and solute ions group near each other, the potential energy of water is reduced. This means that the greater the concentration of solutes, the more osmotic potential is lowered.
Soils collected at “Soils Camp” drying before beginning the aggregate fractionation procedure.
We are interested in varying osmotic potentials because we want to know if crop death seen on saltwater intruded farm fields is due to the inability of plants to pull water out of the soil matrix or because of salt toxicity. This work will be complemented by another experiment of seed germination at varying sodium chloride (NaCl) concentrations in order to tease apart whether seeds are experiencing osmotic stress or ionic/salt stress.
This first year has been a year of logistics! Between field work on the lower eastern shore, to aggregate fractionation at the University of Maryland College Park, to seed germination experiments and George Washington University, I feel like the ring leader of a scientific circus. The second year can only be crazier and more exciting with all the data to analyze and a story to tell!
References:
Six, J., K. Paustian, E.T. Elliott, C. Combrink. 2000. Soil Structure and Organic Matter: I. Distribution of Aggregate-Size Classes and Aggregate-Associated Carbon. Soil Science Society of America Journal. 64:681-689.
Weil, R.R. and N.C. Brady. 2016. The Nature and Properties of Soils. 15th ed. Pearson Education, Columbus. ISBN: 9780133254488