This data set consists of soil properties and extracellular enzymes activities measured during 2014.

This data set consists of monthly averages of soil and litter properties. Rows are grouped in the following order: year, month, vegetation type, plot ID. Within a single month five plots were sampled within each of the 2 vegetation types (10 plots total). Columns F+ represent individual measurements.

This data set consists of monthly averages of soil and litter properties. Rows are grouped in the following order: year, month, vegetation type, plot ID. Within a single month five plots were sampled within each of the 2 vegetation types (10 plots total). Columns F+ represent individual measurements.

We conducted this study in Upper Mississippi River Pools 4 and 8 to document the occurrence and cover of Phalaris arundinacea and other forest floor plants in UMR floodplain forests and relate measures of abundance of Phalaris, and community composition and diversity to estimates of flood duration which can exhibit high spatial heterogeneity. We used modeled inundation duration which allowed us to sample at randomly selected forest “places” across a large spatial scale in forest areas that had a range of tree canopy cover and basal area. We also evaluated changes in plant composition, Phalaris and wood nettle cover and silver maple seedling persistence between years relative to modeled inundation duration. From these repeated samples we also asked whether Phalaris and wood nettle cover the 1st year influenced plant composition the following year. Forest floor vegetation was quantified as percent cover within 5, 4m radius plots: one in the center and 4 others centered 25m from the center plot in the 4 cardinal directions. Percent cover was recorded to the nearest 5% for cover over 5%, to nearest 1 percent below 5%. We also noted species that were rare (1-5 individuals with less than 1%) as 0.1% cover, or numerous with insignificant cover (<1% cover), as 0.5% cover. Summing cover over all species in a plot could yield a number greater than 100, or greater than the total cover estimated for that plot if plant canopies overlapped. The species abbreviations (codes) follow the USDA Plants website conventions (https://plants.sc.egov.usda.gov/home).

We conducted this study in Upper Mississippi River Pools 4 and 8 to document the occurrence and cover of Phalaris arundinacea and other forest floor plants in UMR floodplain forests and relate measures of abundance of Phalaris, and community composition and diversity to estimates of flood duration which can exhibit high spatial heterogeneity. We used modeled inundation duration which allowed us to sample at randomly selected forest “places” across a large spatial scale in forest areas that had a range of tree canopy cover and basal area. We also evaluated changes in plant composition, Phalaris and wood nettle cover and silver maple seedling persistence between years relative to modeled inundation duration. From these repeated samples we also asked whether Phalaris and wood nettle cover the 1st year influenced plant composition the following year. Forest floor vegetation was quantified as percent cover within 5, 4m radius plots: one in the center and 4 others centered 25m from the center plot in the 4 cardinal directions. Percent cover was recorded to the nearest 5% for cover over 5%, to nearest 1 percent below 5%. We also noted species that were rare (1-5 individuals with less than 1%) as 0.1% cover, or numerous with insignificant cover (<1% cover), as 0.5% cover. Summing cover over all species in a plot could yield a number greater than 100, or greater than the total cover estimated for that plot if plant canopies overlapped. The species abbreviations (codes) follow the USDA Plants website conventions (https://plants.sc.egov.usda.gov/home).

c) We examined effects of flooding on supply rates of 14 nutrients in floodplain areas invaded by Phalaris arundinacea (reed canarygrass), areas restored to young successional forests (browsed by white-tailed deer and unbrowsed), and remnant mature forests in the Upper Mississippi River floodplain. Plant Root Simulator ion-exchange probes were deployed for four separate 28-day periods. The first deployment occurred during flooded conditions, while the three subsequent deployments were conducted during progressively drier periods. Time after flooding corresponded with increases in NO3--N, K+ and Zn+2, decreases in H2PO4--P, Fe+3, Mn+2, and B(OH)4-B, a decrease followed by an increase in NH4+-N, Ca+2, Mg+2 and Al+3, and an increase followed by a decrease for SO4-2-S. Plant community type had weak to no effects on nutrient supply rates compared to the stronger effects of flooding duration. Our results suggest that seasonal dynamics in floodplain nutrient availability are similarly driven by flood pulses in different community types. However, reed canarygrass invasion has potential to increase availability of some nutrients, while restoration of forest cover may promote recovery of nutrient availability to that observed in reference mature forests.

c) We examined effects of flooding on supply rates of 14 nutrients in floodplain areas invaded by Phalaris arundinacea (reed canarygrass), areas restored to young successional forests (browsed by white-tailed deer and unbrowsed), and remnant mature forests in the Upper Mississippi River floodplain. Plant Root Simulator ion-exchange probes were deployed for four separate 28-day periods. The first deployment occurred during flooded conditions, while the three subsequent deployments were conducted during progressively drier periods. Time after flooding corresponded with increases in NO3--N, K+ and Zn+2, decreases in H2PO4--P, Fe+3, Mn+2, and B(OH)4-B, a decrease followed by an increase in NH4+-N, Ca+2, Mg+2 and Al+3, and an increase followed by a decrease for SO4-2-S. Plant community type had weak to no effects on nutrient supply rates compared to the stronger effects of flooding duration. Our results suggest that seasonal dynamics in floodplain nutrient availability are similarly driven by flood pulses in different community types. However, reed canarygrass invasion has potential to increase availability of some nutrients, while restoration of forest cover may promote recovery of nutrient availability to that observed in reference mature forests.

The dataset represents the results of floodplain soil samples collected in Navigation Pool 8 of the upper Mississippi River. The objective of the research was to assess the changes in soil chemistry and nutrient transformation at floodplain forest sites in the presence or absence of invasive reed canarygrass (RCG- Phalaris arundinacea) and determine if the RCG effect was modified by the frequency of inundation of the flood plain soils. The data are structured in a 2x4 factorial experimental design, Factor 1, the presence or absence of RCG in floodplain forest landcover and Factor 2, four levels of flood inundation frequency (0.25-0.32, 0.32-1.35, 1.35-2.35, and 2.35-4 events per year). Soil core samples were collected at 6 locations (n=6) by 2 landcovers and 4 inundation frequencies for a total of 48 sites in the June post flood period and again in August of 2019. Rates of biogeochemical transformation of nitrogen was determined for each site. Soil characteristics, Mehlich-3 metals (Al, Ca, Cu, Fe, K, Mn, Mg, Na, P, and Zn), Phosphorus (P), MgCl2 extracted P, carbon, nitrogen, nitrate-nitrite, exchangeable ammonium, and particle-size of the soil were also measured. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

The dataset represents the results of floodplain soil samples collected in Navigation Pool 8 of the upper Mississippi River. The objective of the research was to assess the changes in soil chemistry and nutrient transformation at floodplain forest sites in the presence or absence of invasive reed canarygrass (RCG- Phalaris arundinacea) and determine if the RCG effect was modified by the frequency of inundation of the flood plain soils. The data are structured in a 2x4 factorial experimental design, Factor 1, the presence or absence of RCG in floodplain forest landcover and Factor 2, four levels of flood inundation frequency (0.25-0.32, 0.32-1.35, 1.35-2.35, and 2.35-4 events per year). Soil core samples were collected at 6 locations (n=6) by 2 landcovers and 4 inundation frequencies for a total of 48 sites in the June post flood period and again in August of 2019. Rates of biogeochemical transformation of nitrogen was determined for each site. Soil characteristics, Mehlich-3 metals (Al, Ca, Cu, Fe, K, Mn, Mg, Na, P, and Zn), Phosphorus (P), MgCl2 extracted P, carbon, nitrogen, nitrate-nitrite, exchangeable ammonium, and particle-size of the soil were also measured. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

Input and release of phosphate, nitrate, and ammonium measured using stacked ion-exchange resin bags on top of soil in floodplains along Pocomoke River, Maryland, in order to evaluate the effectiveness of floodplain reconnection on water quality functions.