Understanding Risk in AgricultureWHAT IS CAUSING RISK?

Contact InformationJerry L. HatfieldLaboratory Director National Laboratory for Agriculture and the Environment1015 N. University BlvdAmes, Iowa 50011515-294-5723515-294-8125 (fax)jerry.hatfield@ars.usda.gov

Crop Insurance ClaimsTop 2 insurance claims since 1989◦ Excessive moisture◦ Drought

Is it soil or climate?

Our Changing Climate

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1900 1920 1940 1960 1980 2000

Prec

ipita

tion

(in)

Illinois Precipitation: 1901-2010

30 Year Mean

Annual Mean

Min Limit

Max Limit

y = 0.0002x - 0.0201R² = 0.0082

y = -0.0002x + 0.7504R² = 0.0182

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Ratio

Year

Seasonal Annual: Total Annual Precipitation- Illinois

Spring

Summer

Linear (Spring)

Linear (Summer)

20082010

2011

2012 2013

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0 5 10 15 20

July

-Aug

ust P

reci

pita

tion

(inch

es)

May-June Precipitation (inches)

Spring and Summer Rainfall- Illinois

1895-1980

1981-2013

Dry SpringWet Summer

Wet SpringWet Summer

Dry SpringDry Summer

Wet SpringDry Summer

Extreme Precipitation

Climate trends Increasing precipitation

Shift in seasonality with more spring and more variable summer precipitation

Minimum temperatures are increasing more than maximum

Temperatures are increasing more in the winter than the summer

Rain into the soil Silt Loam Soil

Organic Matter (%)0 2 4 6 8

Day

s of

Ava

ilabl

e So

il W

ater

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Organic Matter (%)0 1 2 3 4 5 6 7

Avai

labl

e W

ater

Con

tent

(%)

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Data Points Sand, AWC = 3.8 + 2.2 OMSilt Loam, AWC = 9.2 + 3.7 OMSilty clay loam, AWC = 6.3 + 2.8 OM

Hudson, 1994

Assuming an average rate of crop water use during the grain-filling period for corn

What are we doing to our soil?

Soil Degradation Spiral

Poor Land Management

Aggregation Degradation

Compaction& crusting

Water & Wind Erosion

Plant Growth Soil Biology

Yield

Reduced Soil Productivity

Paustian et al., 1997

Decrease in OM quantity& changes in OM quality

Soil Organic Matter Changes

Stable Soil SystemsLow Biological Activity High Biological Activity

Low stabilityHigh Stability

Slow infiltration, fast time to runoff

High infiltration,Delays runoff

Entrained material

Unstable microclimate

Stable microclimate StabilitySlow infiltration, fast time to runoff

Variation of Water Holding Capacity within production fields

Soybean Production FieldEarly August Late August

Yield variability in a field comes from soils inability to supply water during grain-filling

65 bu/acre

25 bu/acre

Crop Yield Variation

Good Soils = Good Yields

Mean NCCPI

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Cou

nty

Yiel

d (g

m-2

)

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KentuckyIowaNebraska

Kentucky(Double crop)Y = 131.187 + 187.458X. r2 = 0.72***

Soybean yields across Iowa, Kentucky, and Nebraska

Climate resilience is derived from good soils in rainfed agricultural systems

NCCPI-AG

0.4 0.6 0.8 1.0

Mea

n C

ount

y Yi

eld

(g m

-2)

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1000

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

Maize County Yields

Variation in NCCPI across the Midwest

Yield GapsIowa Maize Story County

Year1950 1960 1970 1980 1990 2000 2010 2020

Yiel

d (k

g ha

-1)

-2000

0

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Attainable YieldActual YieldYield Gap

Iowa Maize Story County

Fraction of Attainable Yield0.0 0.2 0.4 0.6 0.8 1.0

Cum

ulat

ive

Freq

uenc

y

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1.0

We have found that 20% of the yield loss occur 80% of the time due to short term stresses, e.g., we needed an 2 inches but only received 1 inch of rainfall for the week so the plant is under a moderate stress and not fulling its yield potential

“Passive protective blanket” “Active protective blanket”

Role of residue on the soil surface

Stable Microclimate

Temperature profiles in the soil

Extremes in temperature limit the biological activity in the soil, induced by a dry soil

120-130 F85-90 F

Benefits of Using Cover Crops

Reduced erosion Reduced nitrate leachingReduced phosphorus lossesIncreased soil organic matterImproved weed control Support and maintain soil organismsImprove soil structure – especially no-tillGrazing and forage potentialRecycling manure nutrients

Mammals - gophers, moles, mice, groundhogsEarthworms - night crawlers, garden wormsInsects and mollusks - ants, beetles, centipedes, snails, slugsMicrofauna - nematodes, protozoa, rotifers≈Microflora - fungi, yeast, molds, mychorhizaActinomycetes - smaller than fungi, act like bacteriaBacteria - autotrophs, heterotrophs, rhizobia, nitrobacterAlgae - green, blue-green

The “living soil”, a biological system.

Earthworms, insects and rodents are “nature’s plow” and the most visible components of the “living soil” team. They work in tandem with other soil fauna, soil microorganisms and fungi to contribute to aeration and nutrient cycling as part of a “soil factory” team effort.

≈

Carbon Balance in Corn-Soybean Fields 2000-2016Rates(Mg C ha-1 yr-1)

Field Footprint

ΔTC -1.52 ± 0.78

-1.54 ± 0.76

C budget -1.70 ± 0.01

-1.72 ± 0.02

Current state of our soilsContinually lose carbon

Decrease the soil quality and infiltration rate

Increasing the potential for yield variation within fields

Increasing the risk of weather impacts on production

Soil Experiment – Laboratory

Evaluation of cover crop mixtures on changes in soil properties and gas exchange (CO2 and O2)

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3/6/2017 0:00 4/25/2017 0:00 6/14/2017 0:00 8/3/2017 0:00 9/22/2017 0:00 11/11/2017 0:00

SOIL

O2(

kpa)

Soil O2

#3-Control #6-UAN #9-PB #12-PB #15-PB #18-UAN

RiskWe can reduce the risk due to weather and climate changes by increasing the capacity of or soils to cycle water and nutrients.

What do we knowOur weather is becoming more variable

Efficient crop production is dependent upon good weather and a good soil

We can manage the soil to increase climate resilience by increasing water availability and nutrient cycling

Enhancement is soil is only possible by enhancing and maintaining the soil biological system