Chloride Research: What Have We Learned?

C. A. Grant1, R. E. Lamond2 , R. M. Mohr1 and R. E. Engel3

1AAFC - Brandon Research Centre 2Kansas State University

3Montana State University

History of Chloride

• Discovered in Sweden in 1774 by Carl Wilhelm Scheele

• Present in many salts, including KCl, CaCl2 and NaCl

• Recognized as fertilizer as far back as mid 1800’s

• NaCl applied to “stiffen straw”

• Cl- viewed as active ingredient

History of Chloride • Chloride recognised as an essential

nutrient in 1954

• Required in very small amounts for crop growth (~100 mg kg-1)

• Deficiency induced in nutrient solutions

• Cl- widespread in soil and water

• Responses considered unlikely in field

What Does Cl-

Deficiency Look Like?

• Premature wilting

• Chlorosis of newly emerging leaves

• Reduced shoot and root growth

• Roots may show “herring bone” pattern

• Leaf cupping may occur

Field responses occurred where Cl- was above biochemical needs

• Late 1950’s to early 1960’s

• Sugar beets in Manitoba (Soper)

• Corn in US (Younts and Musgrave)

• Increased yield and reduced stalk rot

Effect of K Source and Placement on Grain Yield of Field-Grown Corn

0

5

10

15

20

25

30

35

40

45

Yie

ld (

bu

ac

re-1

)

Control KCl K2SO4

None

In-Row

Broadcast

20 lb K2O acre-1

Younts and Musgrave 1958

Effect of K Source and Rate on Stalk Rot in Field-Grown Corn

12

14

16

18

20

22

24

0 20 60 80 100

K Rate (lb K2O acre-1)

Sta

lk R

ot

(%) KCl

K2SO4

Younts and Musgrave 1958

Field responses occurred where Cl- was above biochemical needs

• Early 1970’s

• Coconut and other plantation crops in Philippines (von Uexkull)

• Late 1970’s - early 1980’s

• Winter wheat in Europe (Russell) and USA (Powelson and Jackson; Taylor and Christenson)

Winter Wheat Grain Yield as Function of N Source

0

1

2

3

4

5

6

7

8

Gra

in Y

ield

(T

ha

-1)

Site A Site B

(NH4)2SO4

NH4Cl

Ca(NO3)2

Christensen et al. (1981)

Reponses Not Due to “Biochemical” Deficiency

• Water relations?• Effects on plant development?• Nitrification inhibitor?• Transport of other nutrients in plant?• Reducing late season lodging?• Kernel weight?• Disease effects?

Response occurs at Cl- much higher than measured essential level

Take-all root rot of winter wheat was reduced by KCl in Oregon

Oregon results triggered interest in Cl- in Great Plains

• Responses to KCl had been noted on high K soils in Montana• Skogley and Haby (1981)• Winter wheat, spring wheat, barley,

potatoes, alfalfa and more• Suggested a problem with K soil test

prediction• Cl- response could be part of the

reason

Great Plains Research

• Will crops on the Great Plains respond to Cl-?

• Which crops will respond?

• What is the mechanism for Cl- response?

• Can we predict where responses will occur?

Cl- has improved crop yields in the Great Plains

• Over 210 trials in KS, MN, MT, ND, SD, MB and SK have evaluated Cl- response in wheat and barley

• Significant yield response in 48% of trials

• Average response of ~5 bu/A

• Cl- responses also occurred in other crops

Wheat and barley responded to KCl while oats did not

2.0

2.5

3.0

3.5

4.0

Gra

in Y

ield

(M

g h

a-1

)

Wheat Barley Oats

0 KCl

187 KCl

Fixen et al. (1986)

8 site-years in South Dakota

Chloride fertilization increased grain corn yield in Kansas

82

84

86

88

90

92

94

96

Gra

in Y

ield

(b

u a

cre-1

)

Control KCl NaCl CaCl2

20 Cl

40 Cl

Lamond et al. 2000

Brown County - 2000

Chloride fertilization increased grain sorghum in Kansas

80

82

84

86

88

90

92

94

96

98

100

Gra

in Y

ield

(b

u a

cre-1)

Control KCl NaCl CaCl2

20 Cl

40 Cl

Lamond et al. 2000

Brown County- 2000

Responses to Cl- are cultivar dependant

• Cultivar differences occur in barley and wheat

• Both spring and winter wheat

• Some of the differences may be due to disease susceptibility

Summary of grain yield responses to addition of 50 kg Cl- ha-1 (Manitoba, 1989-91)

Average Yield Response

(Kg ha-1)

Cultivar Sites with yield increase

Responsive sites

All sites

Katepwa 0 of 8 -- -10

Katepwa 0 of 4 -- -16

Roblin 1 of 4 493 137

Biggar 2 of 4 333 150

Marshall 2 of 4 363 116

Mohr

Chloride Variety Trials

• North American Cl- study

• Texas, Kansas, South Dakota, North Dakota and Manitoba

• 15 winter wheat or spring wheat varieties at each location

• Treatments: 0 Cl- and 40 lb/A Cl-

Response of Winter Wheat Cultivars to Cl- fertilization

Lamond et al. 2000

0

2

4

6

8

10

12

Yie

ld R

esp

on

se

(bu

acre

-1)

Responsive

Non-responsive

Response of Spring or Durum Wheat Cultivars to Cl- Fertilization

Grant et al. 2000

0

1

2

3

4

5

6

7

Yie

ld R

esp

on

se

(b

u a

cre

-1)

Responsive

Non-responsive

Yield Increase May Be Due To Disease Suppression

• Wheat: take-all root rot, common root rot, fusarium root rot, stripe rust, leaf rust, septoria, tanspot

• Barley: common root rot, fusarium root rot, spot blotch

• Corn: stalk rot

KCl application reduced common root rot in barley

60

65

70

75

80

85

90

95

Ro

ot

Ro

t R

ati

ng

(%

)

Control KCl KNO3 CaCl2

Grant and Bailey 1994

KCl application reduced common root rot in wheat

0.0

0.5

1.0

1.5

2.0

2.5

Ro

ot

Ro

t R

ati

ng

Carman Portage

0 Cl

50 Cl

1= clean and 4 = severe

Mohr et al 1992

Cl- reduced leaf rust in winter wheat in Texas

Miller reported at PPI-FAR.org

Application Of Cl- Decreased Leaf Diseases In Marshall Spring Wheat

Septoria and tanspot leaf spot complex

PPI-FAR.org

KCl or Tilt decreased leaf disease and increased grain yield

Fixen et al. 1986 PPI-FAR.org

Flandreau, SD,  1984.Butte spring wheat

Why Would Cl- Decrease Disease Problems?

• Increased water potential restricts infection by pathogens?

• Plants are better able to withstand disease?

• Lowers tissue NO3- which inhibits

crop susceptibility?• Increases soil NH4

+ which inhibits pathogens?• Nitrification inhibition

Oregon Studies Associated Cl- Effect With Plant Water Potential

• Cl- treated plants were more erect at mid-day

• Cl- might affect water potential

• Increased water potential may reduce susceptibility to disease

Osmotic potential of winter wheat leaves as related to Cl- concentration

-22

-21

-20

-19

-18

0.0 0.2 0.4 0.6 0.8 1.0

Chloride Concentration (%)

Os

mo

tic

Po

ten

tia

l (b

ars

)

Christensen et al. 1981

Cl- increased leaf relative water content and grain yield in Butte spring wheat

Fixen et al. 1986

Flandreau, SD,  1984

Effect of K source on tissue nitrate

0.0

0.5

1.0

1.5

2.0

Tis

sue

NO

3-N

at

Bo

ot

(g/k

g)

Carringto

n

Fortuna

Minot

Powers L

ake

Willi

ston

Control

K2SO4

KCl

Timm et al. 1986

Chloride reduced the effect of take-all on grain yield

Christensen et al. 1990

1986-88

Gra

in Y

ield

(b

u/a

cre

)

Cl- Sometimes Increased Yield Without Affecting Disease

• Enhanced crop development

• Higher kernel weight

• Longer grain fill

• Greater rate of kernel growth

• Better water relations

• Reduced lodging

KK22SOSO44 KClKCl

Plant development

Cl- addition increased winter wheat kernel weight

15

20

25

30

35

40

45

10

00

Ke

rne

l W

eig

ht

(g)

1 3 4 5 6 7 8 9

Site

- Cl

+ Cl

Engel et al. 1994

Physiological Leaf Spot Physiological Leaf Spot

“Physiological Leaf Spot”

• Occurs in winter and durum wheat

• Recently reported in barley

• Looks similar to tanspot disease

• Related to crop genetics

• Redwin, Sierra, CDC Kestrel are susceptible

0

10

20

30

40

50

0 2 4 6 8

Plant Cl, g kg-1

Leaf

sp

ot

severi

ty,

%

Y = 1.01 + 39.8 expY = 1.01 + 39.8 exp

(-3.89 X)(-3.89 X)

22RR = 0.82= 0.82

Leaf spots severity is strongly related to plant Cl!

Redwin winter wheat

• 10 field locations MT

• 1.0 g kg-1 plant Cl

• Severity increases exponentially at plant Cl < 1.0 g kg-1 no lesions

Leaf Spot Severity and Plant Cl-

• 6 field locations in MT

• Relationship expressed is similar to Redwin

• Break point = 1.5 g kg-1 plant Cl

Kestrel winter wheat

0

10

20

30

40

50

0 2 4 6 8

Plant Cl, g kg-1

Leaf

sp

ot

severi

ty,

%

Y = 1.67 + 64.6 exp Y = 1.67 + 64.6 exp (-2.45 X)(-2.45 X)

RR22 = 0.98= 0.98

This phenomenon is not a disease !

Chloride Deficient Leaf Spot

• Applications of fungicides have no effect on symptoms

• There is no infectious organism on affected tissue

• Symptoms can be reproduced in solution culture

WB881 durum wheat

- 0 Cl dose -

CDC Kestrel winter CDC Kestrel winter wheatwheat

KK22SOSO44 KClKCl

“Chloride deficient leaf spot syndrome”

Soil testing can help predict Cl response

Based on responsive spring wheat varieties grown Based on responsive spring wheat varieties grown at 36 locations in South Dakota. at 36 locations in South Dakota.

Response

Category Soil Cl Frequency Average

lb/A-2 ft % bu/A

Low < 30 69 4.0

Medium 31- 60 31 2.6

High > 60 0 0.3

-400-400

00

400400

800800

12001200

00 22 44 66 88 1010

Plant Cl, g kgPlant Cl, g kg-1 -1

Yie

ld d

efici

t fr

om

max.,

kg h

aYie

ld d

efici

t fr

om

max.,

kg h

a-1

-1 maximum response linemaximum response line

NS

Significant

Yield response in wheat (size and probability) increase as plant Cl falls below 4 g kg-1

Relationship between available Cl-

and tissue Cl- in Katepwa wheat

R2 = 0.68

R2 = 0.73

0

2

4

6

8

10

0 20 40 60 80 100

Soil (to 60 cm) + Fertilizer Cl (kg ha-1)

Pla

nt

Cl

Co

nc

en

tra

tio

n (

g k

g-1

)

KCl

NaCl

Mohr

Soil test recommendations vary with region

• Montana, North Dakota and Manitoba

• Soil Cl to 24” + fertilizer should equal 30 lb Cl- acre-1

• Saskatchewan

• Apply if soil Cl- to 12” is below 16 lb acre-1

Soil test Cl- content in samples taken by Agvise Lab

Low Soil Cl- Does Not Guarantee a Reponse

• Cultivar effects

• Disease pressure

• Moisture regime

• Other stress effects

Soil testing identifies sites where responses are more likely to occur

What Have We Learned?

• Cl- responses can occur under field situations

• Not strictly a biochemical requirement

• Responses are strongly related to cultivar

What Have We Learned?

• Disease suppression plays a role• Not the sole reason for

benefits• “Physiological leaf spot” is Cl-

deficiency in susceptible cultivars• Cl- application cures the

problem

What Have We Learned?

• Other benefits occur• Kernel weight • Water relations • Lodging resistance • Crop development

• Soil testing and tissue testing can help predict responses

Questions?