Saltwater Intrusion-A Growing Issue for Agriculture

Mr. Christopher Miller, USDA Northeast/Southeast Climate Hubs Liaison/Plant Materials Center

Photo credit: Dr. Jarrod Miller

Land in the U.S. Impacted by Salt6% of land globallyis impacted by salt including 42 million acres of irrigated land in the U.S.

Area of Concern

1-2%

Vulnerable Agriculture in Coastal Areas

Ablemarle-Pamilco Sound-North Carolina

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

NRCS Resource Concerns-Salt ImpactsSoil Erosion-Excessive bank erosion from streams, shorelines, and water conveyance channels threaten to degrade water quality and limit use of land for intended purpose.

Soil Quality Degradation- Concentration of salts leading to salinity and/or sodic soils reducing productivity of land for desired use.

Water Quality Degradation- Excessive salts in surface and ground waters results in salts being transported to irrigation water and/or surface runoff that degrades water quality.

Variations of Salt Tolerances in Plants

- Halophytes- Plants that incorporate saline water into their tissue and exude through glands. (examples: Spartina, Distichlis, Salicornia.)

- Plants that tolerate some soil salt and saltwater flooding (switchgrass, coastal panicgrass, eastern gamagrass). Alsoadapted to drought.

- Plants that tolerate some soil salt but not flooding (saltor fresh water). Some turfgrasses, vegetable crops(asparagus), barley/wheat, sorghum/sudangrass.

- Salt spray adaptability- beach plum, bayberry, holly, grapes

Salinity Trials-Netherlands

Global Classification of Water based on Salinity

Various varieties of the same crop species exhibit inherent differences to salt tolerance.

To make saline agriculture possible, conventional farming techniques would need to be adapted. We have identified four pillars of agriculture, all of which would need to be adapted to make saline agriculture possible:

1. Crop and cultivar choice- inherently wide ranges of tolerances. For most salinity levels, a suitable crop can be identified.

2. Irrigation-best done using drip and more appropriate in medium-coarse textured soils.

3. Fertilization- caution adding fertilizer salts; foliar fertilizers best4. Soil management- Important to improve soil organic matter; minimize

tillage, utilize mulches and residues.

Source: Salt Farm Foundation-Netherlands 2018

Netherlands Dike/Canals

Let’s Focus on Opportunities

Conservation Plants as Specialty Crops on Marginal Lands

Establish saltmeadow cordgrass (Spartina patens) for harvesting as a salt hay (mulch) crop.

Plant a biomass/fiber crop – 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), Arrowwood (Viburnum spp.),

Indigobush (Amorpha fruticosa)– Willow (Salix spp.)-identify salt tolerant selections

Saltmeadow 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.

Advantages of Establishing Salt Hay

Provides erosion resistance between wetland and uplandcrop fields. Volunteers naturally when coastal farmland is abandoned.

Creates desirable and needed high marsh habitat

Potential harvest yield. (3.5- 6.0 tons/ac.)Data collected by UDE

Photo credit: Keryn Gedan, GWU

Native Grass Species for Biomass

High Tide Switchgrass Southampton Prairie Cordgrass

Eastern gamagrass

Native Warm Season GrassRiparian Zone Study(w/USDA-ARS)

CultivarSurvival (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

* Top 3 performing grasses also have some level of salt tolerance

Multifunctional Riparian BufferGrass Species:Eastern gamagrassSwitchgrassCoastal PanicgrassPrairie CordgrassFlowering speciesGoldenrodEvening PrimroseMountian mintNY asterRose mallowSeashore mallow

No Buffer-Vulnerable Crop Field

Brackish Ditchwater > 15 ppt.

Seashore Mallow

Brackish marshes – grows interspersed among other species

Delaware to Florida and Gulf of Mexico coastSelf or cross-pollinated

Perennial (lives 10 years)Non-invasive

Large seeds that contain 18-20% oilOil composition is similar to cottonseed oil which is used for biodiesel

Stems can be used to produce cellulosic ethanol

Seeds can be planted and harvested with traditional farm equipment (on upland).

Salt-tolerant – can use resources not usable by food crops (saline land and water).

Kosteletzkya pentacarpos (a.k.a. K. virginica)

Seashore mallow

Expand Availability of Dormant Cuttings for Soil Bioengineering

ApplicationsGroundsel Bush Willow/Dogwood/Viburnum

Soil Bioengineering: Using Plants in a Structural Function

• 3:1 to 2:1 horizontal/ vertical• Low to moderate energy

environment• Seeding may be included

Live Stakes

It’s ALL in the ROOTS!

Eastern Gamagrass Willow Switchgrass

Salicornia (glasswort)

Etihad Airways Flies the World’s First Flight Using Fuel Made in The UAE From Plants Grown in Saltwater by Khalifa University

January 2019-AbuDhabi to Amsterdam

Growing Halophytic Crops-Salicornia production-Netherlands

Gross income from 1 ha (2.5 acres)- $30,000-$35,000 for restaurant industry

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

Technical ResourcesUSDA Climate Hubs - http://www.climatehubs.oce.usda.gov/

USDA-NRCS Plant Materials Program-http://www.nrcs.usda.gov/wps/portal/nrcs/site/plantmaterials/home/

http://www.salineagricultureworldwide.com

Learn more about Coastal Conservation Plants:NRCS Cape May Plant Materials Center-https://www.nrcs.usda.gov/wps/portal/nrcs/main/plantmaterials/pmc/northeast/njpmc/

Learn more about alternative uses of Native Warm Season Grasses:- Association of Warm Season Grass Producers- www.awsgp.org