Summer droughts impact amount of freshwater entering tidal estuaries. This can increase salt concentrations.
USDA’s Natural Resources Conservation Service supports America’s farmers, ranchers and foresters. We offer financial and technical resources to help producers make conservation work for them. The system of practices we promote is helping them improve their operations, reduce the cost of production and conserve our natural resources for the future.
Particularly vulnerable areas of the East and Gulf Coasts.
Gypsum more effective for finer-textured soils that have more cation exchange sites for sodium. In sandier soils, not needed as much.
Good resources as handouts
Sodic soils generally not a problem in the Eastern US. However, salt can impact soils and crops on a short to mid-term basis.
July 30-230-Christopher Miller
Strategies to Minimize the Impacts of Coastal
Flooding and Saltwater Inundation on Cropland
USDA-NRCS Climate Change
Vulnerability Assessment and Adaptation
Key Climate Change Predictions:
– Coastal storms are expected to increase in frequency and intensity
leading to greater wave heights (storm surges), coastal flooding and
– Sea Levels are projected to continue rising over the next 40 years or
– Increased salinization of near-coastal waters
– Increased flooding frequency of marginal lands
– Changes in plant adaptability in specific locations due to
– Increased competition from weeds/invasive plants
– Increased soil health challenges due to potential increased erosion
and changes in soil chemical and biological processes.
State’s Identified NRCS Plant Materials
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)
Financial + Technical
Financial + Technical
More conservation on
Cape May Plant Materials Center
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.
Vulnerability Assessment of Coastal
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,
Sod Production in
southern NJ Impacted by
Sea Level Rise and Salts
Ablemarle-Pamilco Sound-North Carolina
Corn field impacted by
Prevent the establishment of invasive
undesirable plant species and encourage
the establishment of desired wetland
Saltwater Intrusion as Driver of Agricultural Land Use Change
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
• Higher salinity coastal
flooding (salinity by flood
Ref.-Becky Epanchin-Niell, Resources For The Future
Drivers of Saltwater Intrusion
Reference: The Invisible Flood: The Chemistry, Ecology, and Social Implications of Coastal Saltwater Intrusion.
• 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
Tully and Gedan, UMD/GWU Research
Mitigation of Salt Affected Soils
Potential relatively short term, quick fixes*:
– Allow excess salts to leach through natural rainfall events or irrigate with
• 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
sweet potato 0.8
GMO salt tolerant
salt marsh hay 63.0
Restoration candidate species
Groundwater salinity = 3 – 20 ppt
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
Marshy Hay Cordgrass a.k.a. salt hay
from the natural
marsh for salt hay.
Valued as a weed
Demand is still
high but supply is
low resulting in
Native Grass Biomass Species
High Tide Switchgrass Southampton Prairie Cordgrass
Planting in tilled sandy
loam on the same farm.
Planting Seashore Mallow
in a no-till setting on the
Freeman farm in Sussex
Seeding a Restoration Crop in the
Controlling Invasive Species Spread
Strategic planting of competitive native species to
– 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)*
It’s ALL in the ROOTS!
Eastern Gamagrass Willow Switchgrass
Abundant fine roots
for nutrient absorption.
capacity for retention.
Source: Jack Gallagher, University of DE
Saline Agriculture is a
Alternative to Conventional
Source: Dennis Bushnell, Chief Scientist, NASA- Langley Research Center
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
BMP’s for Coastal Resilience
Select plant species that are tolerant to salinity changes and
Planting flood and salt tolerant plants inland from wetland systems to
prolong viability to rising waters and increased flood frequency (in
Maintaining and enhancing diversity of plantings to help with
changing salinity and flooding conditions.
Source: Maryland’s Adaptation Website:
Classification Electrical Sodium pH
(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
(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
Biogeochemical Effects of Salinization
Increased ionic strength
• Osmotic stress → plant stress or death
• Ion exchange → nutrient mobilization
• pH change → phosphorus release from acid soils
• Clay dispersion → prevent drainage
• Cation bridging → change carbon dynamics
• High sulfate → reduced carbon storage
• Sulfide toxicity → plant stress/death
• Formation of iron-sulfur minerals → phosphorus release