Fallow season cover crops in Mid-South

agriculture productionLisa M. Fultz

Brenda Tubana, James Hendrix, Josh Copes, Sebe Brown, Donna Morgan, Naveem Adusumilli, Al Orgeron,

Kenneth Gravois, Trey Price, Wink Alison, Buddy Pitman, Daniel Fromme, Donnie Miller

Producer questions in Louisiana

• What cover crop(s) should I use

• Plant and termination timing and management• Biomass and nutrient production

• For example - corn – Feb 1

• Rotations

• Weed and disease control

• Wet soils

What cover crops have we tried…• Legumes

• Clovers

• Winter pea

• Hairy vetch

• Sunn Hemp

• Cowpea

• Grasses/Small grains• Wheat

• Cereal rye

• Black oats

• Triticale

• Sorhum/Sudan

• Brassicas• Tillage radish• Canola• Turnips

• Others• Chicory

• Corn

• Soybean

• Cotton

• Sugarcane

• Rice

• Rotations

• Rangeland

DataSIO,NOAA,U.S.Navy,NGA,GEBCO

DataSIO,NOAA,U.S.Navy,NGA,GEBCO

DataSIO,NOAA,U.S.Navy,NGA,GEBCO

©2018Google

©2018Google

©2018Google

ImageLandsat/Copernicus

ImageLandsat/Copernicus

ImageLandsat/Copernicus

Image©2019TerraMetrics

Image©2019TerraMetrics

Image©2019TerraMetrics

5 years of cover crops, no nitrogen fertilization, and conservation tillage

• Increased SOM 29%

• Legumes• Decreased soil pH

• Increased soil moisture

• Greater nitrate-N (22%) and ammonium-N (9%)

• Increased C cycling enzyme activity

• Larger populations of saprophytic fungi

• Grasses & Brassicas• Greater K, Ca, Mg

• Increased total microbial biomass

• Larger populations of AMF

0

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Co

rn g

rain

yie

ld (

bu

ac-1

)

N fertilizer rate (lbs ac-1)

Fallow Legumes Grasses & Brassica

Legumes supplemented N fertilizer applications

Cover crops are scavenging N

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Oct-14 Feb-15 Oct-15 Feb-16 Oct-16

Nit

rate

-N

an

d A

mm

on

ium

-N

(mg

kg-1

)

Sampling date

Nitrate-N Ammonium-N

Biomass degradation

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WK0 WK1 WK2 WK3 WK4 WK6 WK8

% b

iom

ass

rem

ain

ing

Fallow Wheat

Cereal rye + Black oats Cereal rye + Hairy vetch

Wheat + Crimson clover Black oats + Crimson Clover + Radish

Black oats + Wheat + Hairy vetch + Radish Crimson clover + Hairy vetch + Radish

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WK0 WK1 WK2 WK3 WK4 WK6 WK8

Nit

rate

-N (

lbs

ac-1

)

Fallow Wheat

Cereal rye + Black oats Cereal rye + Hairy vetch

Wheat + Crimson clover Black oats + Crimson Clover + Radish

Black oats + Wheat + Hairy vetch + Radish Crimson clover + Hairy vetch + Radish

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Fallow Wheat + Berseemclover

Black oats + WinterPea

Cereal rye +Crimson clover +

Tillage Radish

Bio

mas

s (l

bs

ac-1

)

Grass

Legume

Radish

Weeds

Biomass production and weed suppression

On-farm demonstrations

• 2016 – Conservation Innovation Grant• 10 acres of polyculture cover crops per demonstration

• 16 producers with 19 demonstration fields

• 2018 – Louisiana Conservation Innovation Grant• Cover crops in a rice/soybean rotation

• 2019 – Taylor Foundation Grant• 2 on-farm demonstrations of Best Management

Practices

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Cover crop mix Control Cover crop mix Control

Feb. 1 Mar. 7

Bio

mas

s (l

bs

ac-1

)

Black oats

Hairy vetch

weed

Weed suppression and continued cover crop growth

On-farm trials – Corn & Soybean

• Yields ranged between -9 and +18 lb ac-1

• Insecticide seed treatments• Improved stands of corn, cotton, and soybean following

cover crops

• Runoff water quality• Decreases in turbidity, total suspended solids, and total

dissolved solids

• Greater nitrate and ammonium in cover crops

On-farm trials - Sugarcane

• Yield response was variable • Yield ranged from -5 to +7.1 tons ac-1

• Sugar yields ranged from -1,000 to +1,437 lbs ac-1

• When no N added +1,300 lbs ac-1

• Delaying termination to March• Decreased stalk populations by ~7,000 stalks ac-1

Posters

• #9 – Interaction of winter cover crops and nitrogen applications on corn grain yield, nitrate-N, soil enzymes, and soil microbial composition

• #16 – Evaluation of soil type and seeding rate on cover crop biomass and weed suppression

• #17 – Cool-season annuals effects on soil health in warm-season grass pastures and rangelands in the Mid-South central USA

Thank you

Questions@LSU_SoilMicro

lfultz@agcenter.lsu.edu

225.578.1344

Thank YouQuestions??

@LSU_SoilMicrolfultz@agcenter.lsu.edu

225.578.1344