HOW SOIL HEALTH CAN MITIGATE THE EFFECTS

OF EXTREME WEATHER EVENTS ON FARMS

Reducing the impact on production

CONTACT INFORMATION

Jerry L. HatfieldLaboratory Director National Laboratory for Agriculture and the

EnvironmentDirector, Midwest Climate Hub2110 University BlvdAmes, Iowa 50011515-294-5723515-294-8125 (fax)jerry.hatfield@ars.usda.gov

CLIMATE CHANGE

Precipitation changes

Temperature changes

Moving toward extremes

OBSERVED U.S. TRENDS IN

HEAVY PRECIPITATION

OBSERVED CHANGE IN VERY HEAVY

PRECIPITATION

EROSION: HOW MUCH IS TOLERABLE

THE WIND BLOWS TOO

SPRING PRECIPITATION (AMES)

Ames Spring Precipitation

Year

1880 1900 1920 1940 1960 1980 2000 2020

Pre

cip

ita

tio

n (

inch

es)

0

2

4

6

8

10

12

14

16

18

20

22

Spring Precip (March-May)

Mean Spring Precip

The increase in spring

precipitation has

decreased the

number of workable

field days in April

through mid-May

across Iowa by 3.7 in

1995 to 2010

compared to 1979-

1994

y=-2.5991x+54.048R²=0.45023

10

15

20

25

30

35

40

45

50

55

2 4 6 8 10 12 14 16

Suita

bleFieldDays

April-MayRainfall(inches)

SuitableFieldDays(Apr2-Jun3)versusApril-MayRainfall,IowaAverage(1959-2013)

PROJECTED

PRECIPITATION

CHANGE BY

SEASON

TEMPERATURE CHANGE BY DECADE

OBSERVED U.S. TEMPERATURE CHANGE

PROJECTED TEMPERATURE CHANGE

TEMPERATURE EFFECTS ON EVAPORATION

Air Temperature (C)

0 10 20 30 40 50

Satu

ratio

n V

ap

or

Pre

ssu

re (

kP

a)

0

2

4

6

8

10

12

14

e* = 0.61121 exp(17.502Ta/Ta + 240.97)

𝐸𝑇 =𝜌𝑐𝑝(𝑇0 − 𝑇𝑠)

𝑟𝑎+

𝜌𝑐𝑝[𝑒𝑠 𝑇0 − 𝑒𝑎]

𝛾(1 + 𝑟𝑠

𝑟𝑎)𝑟𝑎

Calculations and plot by C. Anderson

Percentile

95th Percentile

Calculations and plot by C. Anderson

CROP PRODUCTION

US GRAIN PRODUCTION

US Wheat Production

Year

1950 1960 1970 1980 1990 2000 2010 2020

Yie

ld (

bu a

cre

-1)

10

15

20

25

30

35

40

45

50

US Soybean Production

Year

1950 1960 1970 1980 1990 2000 2010 2020

Yie

ld (

bu a

cre

-1)

15

20

25

30

35

40

45

50

US Corn Production

Year

1950 1960 1970 1980 1990 2000 2010 2020

Yie

ld (

bu a

cre

-1)

20

40

60

80

100

120

140

160

180

CURRENT AGRICULTURE IN THE MIDWEST

Midwest Corn Grain Production

Year

1860 1880 1900 1920 1940 1960 1980 2000 2020

Yie

ld (

kg

ha

-1)

0

2000

4000

6000

8000

10000

12000

Michigan

Iowa

Midwest Soybean Production

Year

1920 1940 1960 1980 2000 2020

Yie

ld (

kg

ha

-1)

0

500

1000

1500

2000

2500

3000

3500

Illinois

Indiana

Midwest Sweet Corn Production

Year

1960 1970 1980 1990 2000 2010 2020

Yie

ld (

kg h

a-1

)

1000

1500

2000

2500

3000

3500

Minnesota

Wisconsin

Midwest Potato Production

Year

1860 1880 1900 1920 1940 1960 1980 2000 2020

Yie

ld (

kg

ha

-1)

0

2000

4000

6000

8000

10000

Michigan

Wisconsin

CLIMATE FACTORS

Inputs

Temperature

Precipitation

Solar radiation

Carbon dioxide

Direct

Growth

Phenology

Yield

Indirect

Insects

Diseases

Weeds

Soil is the underlying factor as a resource

for nutrients and water

CROP PROGRESS-IOWA

CROP PROGRESS-INDIANA

Takle, E S, et al., 2013: Earth Interactions 18,

1-8

GOOD SOILS = GOOD YIELDS

Mean NCCPI

0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

Co

un

ty Y

ield

(g

m-2

)

180

200

220

240

260

280

300

320

340

Kentucky

Iowa

Nebraska

Kentucky(Double crop)Y = 131.187 + 187.458X. r

2 = 0.72***

Soybean yields

across Iowa,

Kentucky, and

Nebraska

NCCPI-AG

0.4 0.6 0.8 1.0

Mean

Co

un

ty Y

ield

(g

m-2

)

500

600

700

800

900

1000

Kentucky

IowaY = 436.096 + 478.149X, r2 = 0.58***

MAIZE COUNTY YIELDS

NCCPI

ACROSS THE

MIDWEST

OBSERVATIONS

Tillage increases the soil water evaporation rate

Differences among soils within a field which is related to organic matter content and soil water holding capacity

Water use patterns within a field cause “drought” stress to occur in every year

Organic Matter (%)

0 1 2 3 4 5 6 7

Ava

ilab

le W

ate

r C

on

ten

t (%

)

0

5

10

15

20

25

30

35

Data Points

Sand, AWC = 3.8 + 2.2 OM

Silt Loam, AWC = 9.2 + 3.7 OM

Silty clay loam, AWC = 6.3 + 2.8 OM

CO2 & H2O loss from Low vs High Disturbance Drills

0.38 0.35

3.01

0

1

2

3

4

5

None Low High

Disturbance Type

CO

2 l

os

s (

gC

O2

/m2

/h)

CO2 loss

Evaporation

0

0

0.2

0.4

0.6

0.8

1.0

Ev

ap

ora

tio

n (

mm

/h)

0.70

0.17

0.35

Organic Matter Effects on Available Water Capacity

Silt loam

OM increase from 1% to 4.5%

AWC doubles!

5.7% 22.9% (% by Vol.)

Data from Soil Survey Investigation Reports

(surface horizons only)

- Sands: FL (n = 20)

- Silt loams: IA, WI, MN, KS (n = 18)

- Silty clay loams: IA, WI, MN, KS (n = 21)

Sands AWC = 3.8 + 2.2 (OM)

r2 = 0.79

Silt loams AWC = 9.2 + 3.7(OM)

r2 = 0.58

Silty clay loams AWC = 6.3 + 2.8 (OM)

r2 = 0.76

Hudson, B. D. 1994. Soil organic matter and available

water capacity. J. Soil Water Conserv. 49(2):189-194.

EVAPOTRANSPIRATION

ET = Soil water evaporation + Plant transpiration

Energy

Input

(Net

radiation)

Water Vapor

Gradient

f (temp,

vapor

pressure)

Windspeed

Gradient

Soil Water

Availability

Components of ET

Potential ET (how much could evaporate) vs Actual ET (how much does)

Rate-limitation

WATER USE EFFICIENCY-REALITY

Water Use (mm)

200 250 300 350 400 450 500 550

Yie

ld (

kg

ha

-1)

4000

6000

8000

10000

12000

14000

16000

18000

20000

22000

150 kg ha-1

Yield = 3022 + 27.9 Water Use r2= 0.63

100 kg ha-1

200 kg ha-1

50 kg ha-1

Corn Water Use Efficiency

Water Use (mm)

200 300 400 500 600 700 800 900

Yie

ld (

kg

ha

-1)

8000

10000

12000

14000

16000

18000

20000

22000

24000

26000

28000

Water deficit

need 5 inches more

water to grow 300 bu

corn

IOWA COUNTY YIELDS

Floyd County

Year

1950 1960 1970 1980 1990 2000 2010 2020

Yie

ld (

kg

ha

-1)

2000

4000

6000

8000

10000

12000

14000

Observed Corn Yields

Maximum Corn Yields

Story County

Year

1940 1960 1980 2000 2020

Yie

ld (

kg

ha

-1)

0

2000

4000

6000

8000

10000

12000

14000

Observed Corn Yield

Maximum Corn Yield

Washington County

Year

1940 1960 1980 2000 2020

Yie

ld (

kg h

a-1

)

0

2000

4000

6000

8000

10000

12000

14000

Observed Corn Yield

Maximum Corn Yield

Cass County

Year

1940 1960 1980 2000 2020

Yie

ld (

kg h

a-1

)

0

2000

4000

6000

8000

10000

12000

14000

Floyd County

VARIATION IN YIELDS

Iowa County Maize Yields

Fraction of Potential Maize Yield

0.2 0.4 0.6 0.8 1.0 1.2

Fre

quency

0

5

10

15

20

25

30

Cass County

Floyd County

Story County

Washington County

The majority of the yield losses due to the weather are short-term stresses

20% of the yield

loss occurs 80%

of the time due to

water availability

FEEDBACKS BETWEEN TEMPERATURE

EXTREMES AND CROP WATER USE

Depends upon the soil water status and the

root exploration of the crop

Extreme temperatures increase atmospheric

demand and lead to short-term water stress

even in well-watered or saturated soils

Magnitude of the effect depends upon the prior

soil water conditions and rooting depth

TEMPERATURE EFFECTS ON CORN PHENOLOGY

Corn Hybrid RX730

Days after Planting

0 20 40 60 80 100 120

Tota

l C

olla

rs

0

5

10

15

20

25

Normal Temperatures

Warm Temperatures

Corn Hybrid DK 61-72

Days after Planting

0 20 40 60 80 100 120

Tota

l C

olla

rs

0

5

10

15

20

25

Normal Temperatures

Warm Temperatures

Corn Hybrid XL45A

Days after Planting

0 20 40 60 80 100 120

Tota

l C

olla

rs

0

5

10

15

20

25

Normal Temperatures

Warm Temperatures

Rhizotron study with warm chamber 4C warmer than normal chamber

with simulation of Ames IA temperature patterns.

2139 13700 0 7323 2168 12962 kg ha-1

TEMPERATURE EFFECTS ON CORN PHENOLOGY

Corn Hybrid RX730

Days after Planting

20 40 60 80 100 120 140

Tota

l C

olla

rs

0

5

10

15

20

25

Normal Temperatures

Warm Temperatures

Corn Hybrid DKC61-72

Days after Planting

20 40 60 80 100 120

Tota

l C

olla

rs

0

5

10

15

20

25

Normal Temperatures

Warm Temperatures

Corn Hybrid XL45A

Days after Planting

20 40 60 80 100 120

Tota

l C

olla

rs

0

5

10

15

20

25

Normal Temperatures

Warm Temperatures

Rhizotron study with warm chamber 4C warmer than normal

chamber with simulation of Ames IA temperature patterns.

599 4711 342 3053 0 4197 kg ha-1

RHIZOTRON RESULTSY

ield

(g

/p

lan

t)

Soil Water Levels Soil Water Levels

0.5 1.0 1.5 0.5 1.0 1.5

Normal Temp High Temp (reprod)

0 1

0 2

0 3

0 4

0 5

0 6

0 7

0 8

0 9

0 1

00

Combinations of water

and temperature

stresses cause disruption

in pollination and grain-

fill

LEAF CHLOROPHYLL 2011

Corn 2011

Day of Year

140 160 180 200 220 240 260

Leaf C

hlo

rophyll

Readin

gs

0

10

20

30

40

50

60

70

SuperU 1 PB 0

SuperU 1/3 PB 2/3

SuperU 2/3 PB 1/3

CHLOROPHYLL SUMMATION INDEX

Corn 2009-2010

Summation of Chlorophyll Index Readings

0 500 1000 1500 2000 2500 3000 3500 4000

Yie

ld (

kg h

a-1

)

2000

4000

6000

8000

10000

12000

14000

16000

Data points

Yield = 5019 + 2.78 CIs R2 = 0.84

“Passive protective blanket” “Active protective blanket”

SOIL AGGRADATION CLIMB

Biological Activity

Improved Nutrient Cycling

Organic Matter Turnover

Improved Soil Structure

Improved Water

Efficiency

Yield

Profit

SOIL HEALTH FACTORS

Water holding capacity

Aggregate stability (infiltration)

Rooting depth

Nutrient cycling and nutrient availability

Gas exchange between the soil and the atmosphere (oxygen and carbon dioxide)

Residue cover (living or dead)

Reduced tillage