Does Chloride Deserve My Does Chloride Deserve My Attention?Attention?

American Society of Agronomy American Society of Agronomy

Annual MeetingAnnual Meeting

Denver, ColoradoDenver, Colorado

November 4, 2003November 4, 2003

Paul FixenPaul Fixen

Potash & Phosphate InstitutePotash & Phosphate Institute

This slide set available at: http://www.ppi-ppic.org/ppiweb/napro.nsfAdditional Cl information at: www.ppi-ppic.org/chloride/index.html

Related questionsRelated questions

Can Cl significantly influencesignificantly influence crop growth and development? Chemical and nutritional basics

Does Cl influence the crops I managecrops I manage? Crop sensitivity for deficiency and toxicity

Is Cl an important factor in mymy trade area? Nutrient cycling

Can Cl be managed economically? Dr. Grant and Dr. Lamond

Chlorine the elementChlorine the element

One of the halogensOne of the halogensOccurs in nature only as ClOccurs in nature only as Cl- -

Chloride chemistry terminologyChloride chemistry terminology

Chlorine (Cl):Chlorine (Cl): The name of the element Chlorine gas (ClChlorine gas (Cl22):): A greenish yellow gas with a

choking odor; used to purify municipal water Hypochlorite (OClHypochlorite (OCl--):): Forms when Cl2 reacts

with water; A powerful oxidizing agent sold as laundry bleach

Chloride (ClChloride (Cl--):): The naturally occurring stable form of the element

Chloride in our environmentChloride in our environment

Earth’s crust 0.15%Seawater 1.9%Plants 0.1-1%Table salt 60%Muriate of potash 47%

Chloride - an essential plant nutrientChloride - an essential plant nutrient

Earliest report of Cl crop response in mid 1800s1800s in England ... NaCl (salt) topdressed to stiffen barley straw

Recognized as an essential micro- nutrient since the 1950s1950s

Research in the late 1970s1970s revealed insufficient levels in many areas Phillipines, Europe, NW USA

Wheat and barley responses to Wheat and barley responses to chloride in the Great Plainschloride in the Great Plains

(Over 200 evaluations in KS, MN, MT, ND, SD, SK, TX)(Over 200 evaluations in KS, MN, MT, ND, SD, SK, TX)

Response expressed as wheat bushels

Range of response: -3 to +18 bu/A

Average of all: 2.4 bu/A

(includes nonresponsive varieties & high Cl sites)

Frequency of significant response: 48%

Average significant response: 5.2 bu/A

Roles of chloride in plantsRoles of chloride in plants

Stomatal operation

Due to the accumulation Due to the accumulation of Cl in chloroplasts, of Cl in chloroplasts,

this biochemical need is this biochemical need is likely always met underlikely always met under

field conditions field conditions

Photosynthesis and enzyme activationPhotosyntheticPhotosynthetic

electron transportelectron transport

Transport of other nutrients in plantsWater movement in the cell

Effects of chloride addition on plantsEffects of chloride addition on plants

Disease suppression/enhanced host tolerance

Reduced late season lodging

+Cl-Cl

Accelerated plant

development Increased kernel size or plumpness

Wheat, barley and millet diseases Wheat, barley and millet diseases suppressed by chloride additionsuppressed by chloride addition

Stripe rust

Tanspot

Leaf rust

Take-allCommon root rot

Spot blotch

Septoria Powdery Mildew

Tanspot and Septoria suppresion on flag Tanspot and Septoria suppresion on flag leaves of Marshall spring wheat near leaves of Marshall spring wheat near

Watertown, South Dakota in 1985Watertown, South Dakota in 1985

(Septoria and tanspot incited by Septoria avenae f. sp. triticea and Pyrenophora tritiic-repentis)(Septoria and tanspot incited by Septoria avenae f. sp. triticea and Pyrenophora tritiic-repentis)

56 lb Cl/A

No Cl

Leaf rust suppression on flag leaves of Leaf rust suppression on flag leaves of winter wheat in Bosque county Texaswinter wheat in Bosque county Texas

Pioneer 2158 at anthesis. NH4Cl applied at 40 lbs Cl/A    

Miller, Texas A&M Univ.

Other diseases suppressed by Other diseases suppressed by chloride additionchloride addition

Corn Stalk rot

Potatoes Hollow heart, Brown center

Celery Fusarium yellows

Coconut palm Gray leafspot

Rice Stem rot, Sheath blight

Mechanism of disease effectsMechanism of disease effects

Suppression of pathogen Increased NH4

+ uptake – rhizosphere acidification – competitive disadvantage for root pathogens

Increased Mn availability Reduced plant NO3

- concentrations

Increased leaf turgor potential

Enhanced host tolerance Increased plant turgor reduces the effect of the

pathogen on crop yield

Chloride accumulates in most plantsChloride accumulates in most plants

Leaf bladecollar

20 fold range in plant concentration

Chloride toxicityChloride toxicity

Grundon, Univ. of Queensland; Gartel, Germany

Grape

Marginal necrosis caused byMarginal necrosis caused byspraying Mg or NaCl to preventspraying Mg or NaCl to prevent

stem necrosisstem necrosis

Soybean

Droughted appearance andDroughted appearance andpale green marginal necrosispale green marginal necrosis

Fall soil Cl >60 ppm, leaf > 0.9% Cl Fall soil Cl >60 ppm, leaf > 0.9% Cl for susceptible cultivars (Univ. GA)for susceptible cultivars (Univ. GA)

Shows firstShows firston older leaves,on older leaves,then works itsthen works its

way up the plantway up the plant

Toxic effects of chlorideToxic effects of chlorideSome plants are sensitive to Cl excesses:

Some tree, vine, citrus, vegetable, conifer, and ornamental plants

Tobacco Certain soybean varieties grown in the SE U.S.

Conditions where excesses may occur: Low-lying poorly drained areas Where high water tables occur Confined soils - greenhouses High Cl irrigation water

Cl deficient leaf spot syndromeCl deficient leaf spot syndrome

Leaf spot of previously unknown origin First observed in 1991 on Redwin and Manning

winter wheat in Montana Appears similar to tanspot disease but is not

caused by a microorganism Occurs when wheat tissue Cl < 0.1% and soil Cl

< 10 lb/A (0-24”) Barley flag leaf Cl < 0.09% (Oregon State Univ.)

Not shown by all varieties that are Cl deficient No distinctive deficiency symptoms for all varieties

Cl deficient leaf spot syndrome in Cl deficient leaf spot syndrome in CDC Kestrel winter wheatCDC Kestrel winter wheat

F F-1 F-2F F-1 F-2 F F-1 F-2F F-1 F-2

No ClNo Cl 20 lb Cl/A20 lb Cl/A

Engel et al., Montana State University

Cl deficient leaf spot syndromeCl deficient leaf spot syndrome in winter in winter wheat at mild stage (left)wheat at mild stage (left)

Engel, Montana State University20 lbs Cl/A20 lbs Cl/A

Cl deficient leaf spot syndromeCl deficient leaf spot syndrome on durum on durum grown hydroponically in a growth roomgrown hydroponically in a growth room

Western Plant Breeders 881 durum (WB881)

Engel, Montana State University

Bromide does not substitute for Bromide does not substitute for chloridechloride

WB881 Durum

Engel, Montana State University

Crops known to respond positively to Crops known to respond positively to Cl in the fieldCl in the field

Winter wheat Spring wheat Durum wheat Barley Corn Grain sorghum

Potatoes Rice Pearl millet Coconut palm Celery

Chloride cycling in agroecosystemsChloride cycling in agroecosystems

Sources of Cl Wet deposition Muriate of potash fertilizer (47%) Manure Irrigation water

Losses of Cl Crop removal Leaching

Chloride ion Chloride ion wet depositionwet deposition

Cl, kg/ha

20002000

20012001 20022002

Percent of Soils Testing Medium or Percent of Soils Testing Medium or Lower in K in 2001Lower in K in 2001

North AmericaNorth America43%

Soil chloride levels in the Northern Soil chloride levels in the Northern Great PlainsGreat Plains

10,324 samples collected in 1995

AGVISE Laboratories (Northwood, ND)

52.5% < 30 lb/A52.5% < 30 lb/A

35%

30%44%

47%78%77%

82% 51%

64%

28%

14%

63

54%

89%61%

38%

19% 10%

13% 53%56%

54%55%

Fall 2002 Samples(0-24” samples)

MB

ND

SDMN

65%

Soil samples with chloride < 30 lb/aSoil samples with chloride < 30 lb/a

200 sample pairs from 17 counties collected from June to September, 1999

Oklahoma State Univ.

Cl in Oklahoma soilsCl in Oklahoma soils

Chloride removal by cropsChloride removal by crops

Crop Plant part Cl content

Alfalfa Shoot 7.6 lb/tonBarley Grain 0.024 lb/buWheat Grain 0.026 lb/buPotatoes Tubers 0.06 lb/cwt

Summary: Does Cl deserve my Summary: Does Cl deserve my attention?attention?

Where K fertilization is minimal In non-coastal areas Where fungal disease pressure is high For responsive crops: wheat, barley, corn,

sorghum For crops sensitive to toxicity growing where

soil accumulation is likely Where soil and plant analyses indicates low

levels or unusually high levels

It probably deserves more It probably deserves more attention than its gettingattention than its getting