2019 SWCS International Annual Conference July 28-31, 2019 Pittsburgh, Pennsylvania

1. Strategies to Minimize the Impacts of Coastal
Flooding and Saltwater Inundation on Cropland

2. USDA-NRCS Climate Change
Vulnerability Assessment and Adaptation
Plan-2014
Key Climate Change Predictions:
– Coastal storms are expected to increase in frequency and intensity
leading to greater wave heights (storm surges), coastal flooding and
damage.
– Sea Levels are projected to continue rising over the next 40 years or
more.
Resulting Impacts:
– Increased salinization of near-coastal waters
– Increased flooding frequency of marginal lands
– Changes in plant adaptability in specific locations due to
environmental shifts
– Increased competition from weeds/invasive plants
– Increased soil health challenges due to potential increased erosion
and changes in soil chemical and biological processes.

3. State’s Identified NRCS Plant Materials
Needs 2014-2015
Saltwater buffer recommendations for marginal cropland/edge of
field. Explore alternative crops for production. (DE, NC)
Need more refined coastal plant selection guidelines. (RI)
Plant recommendations for saltwater intrusion-determine upper
salinity tolerances of coastal species. (DE, NJ)
Address shoreline/streambank erosion in areas adjacent to cropland.
(NC, NY, VA)
Control/Suppress spread of invasives like Phragmites into
production fields by incorporating native plants, preferably. (CT)

4. Financial + Technical
Assistance
Financial + Technical
assistance working
together
=
More conservation on
the ground
Cape May Plant Materials Center

5. USDA Climate Hubs Project
Christopher Miller-NRCS Project Liaison
Managing the impact of saltwater inundation from coastal
flooding, will require producers to use more adaptive
agricultural practices. This project will:
1. Provide assessment guidelines for agricultural
producers in vulnerable coastal areas of the Eastern US
and Gulf Coast.
2. Based on the assessment, provide potential mitigation
(short term), adaptation (long term) or
wetland/floodplain easement options in order to reduce
lost farm and forest productivity.
3. Establish pilot plant materials demonstration and
evaluation plantings to help determine various plant
species’ adaptability to salt affected fields.

6. Vulnerability Assessment of Coastal
Flooding
Source: Titus, James G. and Charlie Richman. Map of Lands Vulnerable to Sea Level Rise:
Modeled elevations along the U.S. Atlantic and Gulf Coasts. Climate Research, Vol. 18,
November 2001

7. Sod Production in
southern NJ Impacted by
Sea Level Rise and Salts

8. Vulnerable
Agriculture in
Coastal Areas
Ablemarle-Pamilco Sound-North Carolina

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10. What happens when farming
stops?

11. Corn field impacted by
flooding
Phragmites
invasion
Prevent the establishment of invasive
undesirable plant species and encourage
the establishment of desired wetland
plants.

12. Saltwater Intrusion as Driver of Agricultural Land Use Change
1992-2017
Agricultural land more
likely to have transitioned
to natural land when:
• Close to coastal waters
• Low elevation (with respect
to sea level)
• High coastal flood frequency
• Higher salinity waters nearby
(salinity by distance
interaction)
• Higher salinity coastal
flooding (salinity by flood
frequency interaction)
Increased SWI
Ref.-Becky Epanchin-Niell, Resources For The Future

13. Drivers of Saltwater Intrusion
Reference: The Invisible Flood: The Chemistry, Ecology, and Social Implications of Coastal Saltwater Intrusion.
Bioscience:May 2019

14. • Saltwater intrusion results in complex
biogeochemical changes in the soil
• Legacy N and P are released and moving
from fields to marshes.
• Carbon sequestration increased at field
edges and along ditches. Field edges will
migrate inland.
Tully and Gedan, UMD/GWU Research

15. Mitigation of Salt Affected Soils
Potential relatively short term, quick fixes*:
– Allow excess salts to leach through natural rainfall events or irrigate with
fresh water.
• Incorporate rotations of salt tolerant crops alternating with applying water.
– Add gypsum-Conservation Practice Code 333-Amending Soil Properties with
Gypsum Products. Not as effective on sandy soils with lower CEC
– Incorporate composts that don’t contain salts.
• Avoid sewage sludge, most manures and mushroom compost
– Grow cover crops for one season or in rotations
• Small grains esp. barley, Triticale, sorghum, sorghum/sudangrass, canola,
some millets and tall wheatgrass have especially good salt tolerance.
*Site/soil specific, as well as producer specific

16. Let’s Focus on Opportunities

17. Potential Adaptation Strategies

18. Adapt
Crop
Salinity
tolerance
(ppt)
sweet potato 0.8
corn 0.9
tomato 1.3
soybean 2.7
wheat/barley 3.3/8.0
sorghum 5.6
GMO salt tolerant
soy 6.0
canola/rapeseed 7.0
switchgrass 17.5
salt marsh hay 63.0
Conventional crops
Alternative crops
Restoration candidate species
Groundwater salinity = 3 – 20 ppt

19. Growing/Establishing Conservation
Plants on Marginal Lands
Establish saltmeadow cordgrass (Spartina patens) for
harvesting as a salt hay (mulch) crop.
Plant a biomass/fiber crop as a multifunctional buffer
– Switchgrass (Panicum virgatum)
– Coastal Panicgrass (Panicum amarum var. amarulum)
– Prairie cordgrass (Spartina pectinata)
– Seashore mallow (Kosteletzka virginica)
Harvest native shrub stems for soil bioengineering
applications on brackish shorelines
– Groundsel bush (Baccharis halimifolia)
– High tide bush (Iva frutescens), sweetfern (Comptonia peregrina),
Arrowwood (Viburnum spp.), Indigobush (Amorpha fruticosa)
– Willow (Salix spp.)-identify salt tolerant selections

20. Marshy Hay Cordgrass a.k.a. salt hay
(Spartina patens)
Once harvested
from the natural
marsh for salt hay.
Valued as a weed
free mulch.
Demand is still
high but supply is
low resulting in
high cost.
Varietal selections
being evaluated.

21. Native Grass Biomass Species
High Tide Switchgrass Southampton Prairie Cordgrass
Eastern gamagrass

22. NRCS Plant Materials/ARS
Riparian Buffer Study-Field Trial

23. Native Warm Season Grass
Riparian Zone Study(w/USDA-ARS)
Cultivar
Survival (2006) Vigor (2006) Yield (2005) Overall
Relative ranking (1=best, 9=worst)
Red River PC* 1 1 4 2.0
Hightide SG* 2 3 1 2.0
NY EG * 4 2 2 3.0
Shelter SG 3 4 3 3.3
Osage IG 7 5 7 6.3
Niagara BB 5.5 6 8 6.5
Suther BB 5.5 8.5 6 6.7
Suther IG 8 8.5 5 7.2
Bonilla BB 9 7 9 8.3
* Salt tolerant species

24. Seashore mallow

25. Planting in tilled sandy
loam on the same farm.
Planting Seashore Mallow
in a no-till setting on the
Freeman farm in Sussex
County, Delaware.
Seeding a Restoration Crop in the
Transition Zone

28. Controlling Invasive Species Spread
Strategic planting of competitive native species to
control phragmites:
– Spartina pectinata (prairie cordgrass)
– Spartina patens (saltmeadow cordgrass)
– Panicum virgatum (switchgrass)
– Tripsacum dactyloides (Eastern gamagrass)
– Kosteletzkya virginica (Seashore Mallow)
– Other potential species to add:
• Spartina cynosuroides (giant cordgrass)
• Sporobolus virginicus (seashore dropseed)
• Arundinaria gigantea (giant cane)
• Iva frutescens (High tide bush)*
• Baccharis halimifolia (Groundsel)*

29. It’s ALL in the ROOTS!
Eastern Gamagrass Willow Switchgrass

30. Transitioning Refreshable
Buffer Zones
Abundant fine roots
for nutrient absorption.
Harvesting refreshes
capacity for retention.
Source: Jack Gallagher, University of DE

31. Conventional/Historical “Wisdom”
Seawater/Saline incursions/Occurrences
Detrimental-to-Disastrous for
Agriculture
Unconventional
Saline Agriculture is a
Viable-to-Desirable
Alternative to Conventional
Agriculture
Source: Dennis Bushnell, Chief Scientist, NASA- Langley Research Center

32. Saltwater Intrusion into Farmland
• A local, as well as a global, issue
• Saltwater intrusion affects significant areas of the
coastal counties of the East and Gulf Coasts.
• Investigating options for farmers affected by
saltwater intrusion (Chesapeake Bay MD,
VA/Albemarle-Pamlico Sound, NC)
• Working to provide NRCS/District conservation planners
and producers with more information on the costs and
benefits of various alternative choices

33. Technical Resources
USDA Climate Hubs - http://www.climatehubs.oce.usda.gov/
USDA-NRCS Plant Materials Program-
http://www.nrcs.usda.gov/wps/portal/nrcs/site/plantmaterials/home/
USDA-NRCS- http://www.nrcs.usda.gov/wps/portal/nrcs/site/national/home/
Cooperative Extension Service (state specific)

34. BMP’s for Coastal Resilience
Select plant species that are tolerant to salinity changes and
increased temperature.
Planting flood and salt tolerant plants inland from wetland systems to
prolong viability to rising waters and increased flood frequency (in
tidal systems).
Maintaining and enhancing diversity of plantings to help with
changing salinity and flooding conditions.
Source: Maryland’s Adaptation Website:
www.dnr.state.md.us/climatechange

35. Classification Electrical Sodium pH
Conductivity Adsorption
(dS/m) Ratio (SAR)
Saline >4.0 <13 <8.5
Sodic <4.0 >13 >8.5
Saline-Sodic >4.0 >13 <8.5
Interpretation of electrical conductivity
EC
(dS/m) Salt rank Interpretation
0-2 Low Very little injury to plants
2-4 Moderate Sensitive plants may suffer
4-8 High Non-salt tolerant plants will suffer
8-16 Excessive Only salt-tolerant vegetation will grow
16+ Very Excessive Very few plants will grow
Salt Affected Soil Classification

36. Biogeochemical Effects of Salinization
Increased ionic strength
• Osmotic stress → plant stress or death
• Ion exchange → nutrient mobilization
Alkalinization
• pH change → phosphorus release from acid soils
• Clay dispersion → prevent drainage
• Cation bridging → change carbon dynamics
Sulfidation
• High sulfate → reduced carbon storage
• Sulfide toxicity → plant stress/death
• Formation of iron-sulfur minerals → phosphorus release