Promoting success in thin layer sediment placement: effects of sediment grain size and amendments on salt marsh plant growth and greenhouse gas exchange

Thin layer sediment placement (TLP) is a method to mitigate factors resulting in loss of elevation and severe alteration of hydrology, such as sea level rise and anthropogenic modifications, and prolong the lifespan of drowning salt marshes. However, TLP success may vary due to plant stress associated with reductions in nutrient availability and hydrologic flushing or through the creation of acid sulfate soils. This study examined the influence of sediment grain size and soil amendments on plant growth, soil and porewater characteristics, and greenhouse gas exchange for three key US salt marsh plants: Spartina alterniflora, Spartina patens, and Salicornia pacifica. We found that bioavailable nitrogen concentrations (measured as extractable NH4+-N) and porewater pH and salinity were found to have an inverse relationship with grain size, while soil redox was more reducing in finer sediments. This suggests that utilizing finer sediments in TLP projects will result in a more reduced environ..., Coastal marsh plant taxa, including Spartina alterniflora (synonym Sporobolus alterniflorus), Spartina patens (synonym Sporobolus pumilus), and Salicornia pacifica, were obtained from restoration nurseries (Native West Nursery, San Diego, CA & Pinelands Nursery, Columbus, NJ and propagated during the 2018 growing season in a roof-top greenhouse in Philadelphia, PA (39.9539°, -75.1878°) in benthic sediments like those used in thin layer sediment placement projects. Plants were tempered over two weeks to a final salinity of 20‰, using a mixture of water collected from a local marsh at Barnegat Bay, NJ (39.7483°, -74.1931°) and distilled water. Plants were exposed to ambient light conditions under 15% shade cloth, and the greenhouse was outfitted with several fans for temperature moderation. Following a 3x4 factorial design replicated four times, these three plant species were propagated in four types of homogenized sediments of contrasting textures over the course of a growing season ..., , # Promoting success in thin layer sediment placement: effects of sediment grain size and amendments on salt marsh plant growth and greenhouse gas exchange

We have presented data and code used for data analysis. Data includes data for experiment 1, where we analyzed soil and plant traits for plants grown in several sediment textures, experiment 2, where we analyzed soil and plant traits for plants grown in coarse sand with several soil amendments (biochar, compost, biochar and compost), and experiment 3, where we grew plants in sediments prone to acidification with and without biochar amendments.

## Description of the data and file structure

There are three data files provided: (1) Experiment1AllData_corrected_CH4.cvs; (2) Experiment2AllData.cvs; (3) Experiment3AllData.cvs.

### Experiment 1: Where we analyzed soil and plant traits for plants grown in several sediment textures

Experiment1AllData_corrected_CH4.cvs

There are 30 fields in this file, consisting of the following column...