plant nutrient interactions in soil environment

Far West Washington Winter Conference 2011

Plant Nutrient Interactions in Soil Environment

Wesley HaunAgronomist Sales & Research

Far West Agribusiness AssociationWashington Crop Production Conf.Dec. 14, 2011


Sulfur Secondary nutrient essential for plant

growth. In some crops there can be similar

amounts of S as phosphorus (P). Critical in plant metabolic functions.

Component of some amino acids, vitamins, and enzymes.

Photosynthesis and seed formation.


Sulfur Deficiency

Sulfur (S) continues to present challenges as to plant available soil SO4

2- and consistently correlate soil additions to predictable yield response.


Soil Sulfur Deficiencies In U.S.

Sulfur deficiencies tend to be most prevalent in Great Plains, Northeast, California, and Southeast.

In Canada:Western areas


Sulfur Sulfur is critical in conversion of nitrate

(NO3) S – deficiency N – deficiency N-S interaction & deficiency symptoms Similar in early growth stages Significantly different in later growth

stages


Factors Influencing Soil Sulfur Availability

Low Organic Matter (OM)

Course textured soils (sandy)

Well drained soils

Low soil pH


Factors Influencing Soil Sulfur Availability

SO42- adsorption to soil colloids

decrease as soil pH increases.

SO42- reacts w/OH ions of Fe & Al.

Liming soils decrease SO42- adsorbed

& increase amount of SO42- in soil

solution.


Sulfur & Alkaline Soils

Availability of S in alkaline soils is function of amount of sulfate salts present (CaSO4) and OM in root zone.

Primary sources of S in alkaline soils are inorganic compounds.

Kaolinite clays retain more SO4 than Montmorilloite clays.


Natural Sources SO42-

Organic Matter (OM)

Atmospheric Sulfur

Soil Minerals


Atmospheric Deposition Significant amounts of S to growing

crop & soil

Sources:

Burning of gas, coal, oil, and anaerobic decomposition of OM


Atmospheric Deposition

S enters the atmosphere as:

SO2

H2S

H2SO4

others

Nitrogen Mineralization and Nitrification

Soil Organic Matter

Manure

Rotting Plant Residues

+

Mineralization Nitrification

NH3

Ammonia

NH4+

Ammonium

NO2-

Nitrite

Oxygen

NO3-

NitrateBacteria

NitrosomonasNitrobacter


Sulfur Cycle

Soil Organic S

H2S FeS

Elemental S

SulfateAerobic Conditions

Thiobacillus, Beggiatoa, Thiothrix

Anaerobic Conditions

Beggiatoa, Thiothrix

Leaching


Sulfur Mineralization

Organic S Decay Products

Sulfates

Bacteria

Bacteria

(OM) (H2S, other organic sulfides)

(SO4 )


Sulfur Mineralization Similar to Nitrogen (N)

Mineralization process.

Driven by correct Temperature

Moisture

Oxygen

Microbial activity

S Particle size


Sulfur Oxidation

H2S + O2 H2O + S

S + O2 + H2O H2SO4

Oxidation of S results in H2SO4

Lowers soil pH

Bacteria

Bacteria

CaCO3 + H2SO4 CaSO4 + H2CO3


Sulfur Cycle

Soil Organic S

H2S FeS

Elemental S

SulfateAerobic Conditions

Thiobacillus, Beggiatoa, Thiothrix

Anaerobic Conditions

Beggiatoa, Thiothrix

Leaching


Effect of Soil Temperature on S Oxidation

0

10

20

30

40

50

60

70

80

Soil 1 Soil 2 Soil 3 Soil 4 Soil 5

SO4

Lev

el(p

pm)

Soils

41o F

69o F

80o F

SoilTemp.


S Particle Size Affects Rate of Oxidation

Particle Size(mesh/inch)

2 weeks 4 weeks

20 – 40 5 14

40 – 80 15 36

80 - 120 36 68

120 - 170 61 81

230 80 82

% Sulphur Oxidized


Oxidization of Elemental Sulphur

Elemental sulphur particle sizeThe smaller the particle size the faster the conversion to SO4

=

T90CR pastille T90CR drop of water T90CR fine powder

90 % Elemental Sulphur

10 % Dispersing Agent


Soil pHRegulates plant nutrient availability. Influences micro-organism

population.Bacteria --- pH > 6.5Thiobacillus -- S oxidation

Fungi --- pH < 6.5N fixation --- pH > 6.0 P availability --- pH 6.5 – 7.5

Relationship Between Soil pH and Plant Nutrient Availability

Adapted from Truog, 1946. SSAP 11:305-308.

4 5 6 7 8 9 10

Nitrogen

MolybdenumCopper and Zinc

ManganeseIron

MagnesiumCalcium

SulfurPotassiumPhosphorus

Boron


Effect of Soil pH on Phosphorus Availability

Rel

ativ

e P

Fixa

tion

In S

oil

VeryHigh

4 5 6 7 8

High

Medium

Low

GreatestFixation

HighFixation

MediumFixation

Range For HighestP Availability

FixationBy

Iron FixationDue To

Aluminum

FixationBy Calcium

Soil pH


Sulfur Uptake by Plants

SO42-

Is not pH sensitive

Relatively insensitive to high SO4

2- concentrations in soil


Croplbs SO4

2-

/unitYieldbu/Ac

Uptakelbs/Ac SO4

2-

Wheat 0.25 40 10.0

Sugar Beets 1.5 30 tons/Ac 45.0

Alfalfa

Potatoes

Corn

5

0.04

0.163

3.5 tons/Ac

400 cwt/Ac

140

18

17

23

Sulfur Uptake by Crop


Sulfur Deficiency in Plant Best Method to Diagnose Plant tissue analysisSoil sample

Sulfur conc. 0.2 – 0.5% in plant tissue S deficiency NO3 accumulationBalancing S & N nutrition is important

for plant & animal health.


Sulphur ApplicationTimingFallSpring Soil TemperatureOptimum range 75 – 85o F


Sulphur ApplicationProduct SuggestionsTiger 90CR90% Sulphur


Fall Applied Tiger 90CR Sulphur


Sulfur & Other Nutrient Interactions

Optimum S & K levels enhance Zn Uptake Fazili et al (2008) lack of S limits N use

efficiency Kowalenko & Lowe (1975) – high N:S ratio

decreased S mineralization optimum ratio at 7:1

Excess SO4 can reduce uptake of NO3 & MoO4 Excess NO3 can reduce uptake of SO4 S can reduce Cu toxicity w/Cu – S complexes


Soil Sulfur determination compounded by several factors: Soil Sulfur. (OM, Minerals) Sulfur in precipitation. (SO4

2-) Atmospheric Sulfur. (SO2) Sulfur in soil/crop amendments.

(manure, fertilizer)

Soil Testing for Sulfur


Soil Testing for SulfurCollection patternFactors that influence TopographySoil TypeCrop HistoryManure applications


Soil Testing for Sulfur

Collect samples from root zone. 0 - 12 inches deep.


Plant Tissue Sampling Procedures

Appropriate plant tissue. Seedlings – whole plant Mature plants – leaf/stems

Same stage of development. Soil samples w/complete

analysis.


Tissue Sample Collection Most recent mature leaves just below

growing point on main stems. Select material without soil particles. DO NOT wash. Do not select dead/deteriorated material. Collect samples ASAP after symptoms

appear.


Sulfur Deficiency in Alfalfa


Sulfur Deficiency in Alfalfa

Photo: Brian Lang, ISU


Sulphur in AlfalfaSoil Test < 8 ppmPlant tissue test < 0.20%Apply:50 lbs/ac NH4SO4 or K2SO4

75lbs T90CR


Sulfur Deficiency in Corn

Photo: Brian Lang, ISU



Photo: John Sawyer, ISU



Soil test value < 8 ppmPlant tissue value < 0.20%Apply:20 – 30 lbs/Ac sulfur


Sulphur Deficiency in Potatoes

Photo: Univ. of Idaho


Sulphur Deficiency in Potatoes

Soil test value < 7 ppmPlant tissue value < 0.20%Apply:10 – 20 lbs/Ac S


Sulphur Deficiency in Sugar beets

Photos: Univ. of Cal - Davis


Sulphur in Sugar Beets

Sulphur should not be limitingS is constituent of 3 amino acids

and critical in protein synthesisSoil test < 10 ppm in top 12 inchesApply 30 – 40 lbs/Ac S


Sulphur in Sugar Beets

Interacts w/N & both nutrients effectiveness is improved.Enhances sugar quality.


Sulfur Deficiency in Wheat


Sulfur Deficiency in Wheat

Soil test value < 8 ppmPlant tissue value < 0.20%Apply:20 – 30 lbs/Ac S


Sulfur impacts wheat flourbaking quality


SummarySulphur is an essential nutrient for plant

growth.Plant sulphur deficiencies are more

prevalent.Sulphur mineralization is similar to

nitrogen mineralization process.Primary crops grown in PNW

have relative high demand for sulphur.


SummarySeveral factors influence S availability Soil Type, S particle size, soil

temperature, micro-organism(Thiobacillus) population.

A planned Sulphur nutrient mgt program provides more consistent SO4availability from year to year.

plant nutrient interactions in soil environment

Documents

sulfur sulfur

sulfur deficiency sulfur

soil sulfur deficiencies

sulfur mineralization

soil solution

soil additions

plant available soil

similar amounts of s