Coastal soils: Issues with salinity

Mark Battany, Viticulture/Soils Farm AdvisorSan Luis Obispo & Santa Barbara Counties

Quick review of salinity

Vineyard soil

Irrigation Evapotranspiration

Pure waterWater + salts

Salts in root zone

Salts below (or away from) root zone

Leaching

Three salinity situations

• Restricted drainage– Salts can accumulate to high levels

• No leaching of rootzone– Salts can accumulate to high levels

• Free drainage conditions, occasional leaching– Salts can increase, but to some limit– Will still affect vineyard performance

Restricted drainage

East of Mendoza, Argentina

Limited natural rainfall leaching

Valle del Elqui, Chile

Occasional leaching

19531956

19591962

19651968

19711974

19771980

19831986

19891992

19951998

20012004

20072010

0

5

10

15

20

25

30

35Paso Robles winter rainfall, 1952/53 - 2010/11

Year

Winter rain-fall,inches

Effects on soil chemistry

• Electrical conductivity (ECe)– Plant growth decreases as soil EC increases

• Sodium– Degrades soil structure, toxicity at high levels

• Chloride, boron– Toxicity at high levels

• Bicarbonate– Increases soil physical degradation

• pH – Nutrient availability

Salt source: groundwater

0

1

2

3

4

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 53 55

Well water ECw

(dS/m)

Data from 56 wells in the Paso Robles areaSource: Paso Robles Groundwater Basin Study

Increasing problem potential

Major problem potential

Vine productivity vs. soil EC

Soil EC (dS/m)

0 1 2 3 4 5 6 7 8 9 10

Relative growth oryield

0%

100%

Specific toxicity

Sodium

Sodium salts;disperse organic matter & clay

Calcium salts;from amendments

Soil structure degradation• Effects of sodium

and bicarbonate

Soil degradation >>>

Vine growth,yield

Paso Robles salinity survey

PasoRobles

San Miguel

Shandon

PasoRobles

San Miguel

Shandon

6.5

0.6

3.0

4.2

5.4

1.8

Soil EC(dS/m)

2006 data

2006-2009 salinity surveysAverage soil electrical conductivity (ECe)

2.802.512.23

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

2006 2007 2009

Year

ECe (dS/m)

Soil EC values (2007)

0

20

40

60

80

100

0 2 4 6 8 10

Soil electrical conductivity, ECe (dS/m)

Relative growth

(%)

43% exceeded threshold

Deeper soil salt fate

Samples taken in May 2010,after relatively wet winter

Irrigation water analysis

meq/L mg/L

pH ECw SAR Ca Mg Na Cl HCO3 B

7.8 1.81 4.6 3.4 6.0 9.9 6.4 4.8 0.93

Each season of irrigation water (1.25 ft) applies about 775 lbs of sodium per acre, and about 3.1 lbs of boron per acre

Bicarbonate hazard low: Ca + Mg > HCO3

Sample site: Clay content

Clay (% )

192022232528313333

30

60

90

120

150

180

210

240

0

Vine row Row m iddle

Soil depth(cm )

Percent clay

Sample site: pH

pH

5.86.06.26.46.66.87.07.27.4

30

60

90

120

150

180

210

240

0

Vine row Row m iddle

Soil depth(cm )

Soil pH

Sample site: ECe

ECe(dS/m )

1.01.52.02.53.03.54.04.55.0

30

60

90

120

150

180

210

240

0

Vine row Row m iddle

Soil depth(cm )

Electrical conductivity

Sample site: Sodium

Na (m eq/L)

469121518212427

30

60

90

120

150

180

210

240

0

Vine row Row m iddle

Soil depth(cm )

Sodium

Sample site: Cl

Cl (m eq/L)

1357911131517

30

60

90

120

150

180

210

240

0

Vine row Row m iddle

Soil depth(cm )

Chloride

Sample site: Boron

B (m g/L)

0.00.10.20.30.40.50.60.7

30

60

90

120

150

180

210

240

0

Vine row R ow m iddle

Soil depth(cm )

Boron

Managing vineyard salinity

• Measure soils and water; heed recommendations• Correct any drainage problems• Adjust water chemistry• Apply gypsum (or acid) as needed• Leach with irrigation when rainfall insufficient• Use tolerant rootstocks, varieties

Field salinity measurement

Drainage

Adjust water chemistry

• Acidification– Acid injection– Sulfur burner– Critical to manage waters with high pH

and bicarbonates• Blending with better water if available• Reverse osmosis not feasible economically• Miracle devices...magnets, electrodes, etc.

Gypsum

• Helps displace sodium• Counteracts bicarbonate• Can use acid instead if

soil has “free lime”• Still need leaching water

to remove sodium• Gypsum will raise soil EC

slightly

Additional leaching

Use more tolerant rootstocks

Soil EC (dS/m)

0 1 2 3 4 5 6 7 8 9 10

Relative growth oryield

0%

100%1103P, 140RSalt Creek

Use more tolerant varieties

Example: Syrah vines in a block of Cabernet Sauvignon

Summary

• Central Coast salinity conditions are manageable (for the most part) but will require attention to keep impacts from becoming economically damaging

• Thanks:– American Vineyard Foundation– ASEV– Grower support on Central Coast

Retrofitting with sprinklers

Salt toxicities