ORGANIC GRAIN CROP RESEARCH AT THE UNIVERSITY OF MISSOURI

Researchers: Tim Reinbott, Robert Kremer, Newell Kitchen, Debi Kelly, Ray Massey, Kerry Clark, Amanda Wolfgeher, Dara Boardman, Steven Easterby

COVER CROP BEFORE HARVEST

PLOWING UNDER COVER CROPS

THE EVILS OF TILLING

Loss of Organic Matter Soil structure Soil microbial

biomass Release of CO2

Soil Erosion

Why Till? Weed Control

TILLED VS NO-TILL-WE HAVE LOST NEARLY 1 FT OF TOP SOIL

LONG TERM NO-TILLTILLED IN A CORN/SOYBEAN/WHEAT ROTATION

SOIL EROSION-EVEN WITH NO-TILLAGE

SANDY LOAM SOIL

TYPICAL SOIL PUDDELING AFTER A RAIN OF AN ERODED SOIL-LOSS OF SOIL STRUCTURE

HOW DO YOU MAINTAIN OR IMPROVE SOIL QUALITY?

A THICK MULCH TO NO-TILL INTO

MORE TO COVER CROPS THAN JUST NITROGEN

From Steve Groff

Cover Crop

No Cover Crop

COVER CROPS REDUCE WATER RUNOFF OR INCREASE WATER INFILTRATION

SOIL PHYSICAL PROPERTIES FOLLOWING 3 YEARS OF COVER CROPS

Treatment Water-Aggregate Stability Pentrometer Bulk

% Increase over control % increaseMg/m3

Corn/Soybean 1.32 Corn/rye/soybean/rye 9 19 1.24 Corn/rye/soybean/hairy vetch 13 8 1.23 Corn/rye/soybean/Hv+rye 17 16 1.23

From Villamil, et al 2006

CAN COVER CROPS AND NO-TILL DECREASE GREENHOUSE GASES?

United States Greenhouse Gas Emissions, 2010

Image created by EPA

But other gases have a greater potential to warm the climate.• Methane (CH4): 20 x

more effective at warming the atmosphere than CO2.

• Nitrous oxide (N2O): 300 x more effective.

Carbon Dioxide (C02) is the most prevalent greenhouse gas.

The Culprits: Greenhouse Gases

CO2 LEVELS OVER TIME

CO2 EMISSIONS AND CARBON STORAGE

Agriculture 25% of CO2 Sources Tillage, N Production,

Cover Crops Decrease CO2 Release from Increased C Storage

However, With Tillage Much of the Benefit is Lost

Cover Crops with Tillage Less C Storage than No-Tillage without Cover Crops

GREENHOUSE GASES IN AGRICULTURE

U.S. Nitrous Oxide Emissions

Image created by EPA

Agriculture is the main source of nitrous oxide in the U.S., due in large part to nitrogen-based fertilizers, but residue breakdown also contributes

NITROUS OXIDE-N20 CONTRIBUTED BY AGRICULTURE

Anerobic Conditions wet

Nitrogen Fertilization 1.5% of all N is lost

as N20

Animal Manures/Compost

N from Cover Crops?

THIS IS WHAT HAPPENEDIN 2008, 2009, 2010, 2011

WHAT ARE WE DOING?

WHERE IS THIS RESEARCH TAKING PLACE

Bradford Research Center, 5 miles east of Columbia, MO (Boone County)

Organic Farmer Cooperators: David Gray, Montgomery County, MO Warren Wilson, Audrain County, MO Terry Littrell, Audrain County, MO James Maberry, Livingston County, MO

RESEARCH OBJECTIVES

USDA-NIFA OREI Grant Greenhouse gas emissions from organic production

using tillage with and without cover crop and no-till with cover crop

How to plant corn into a cover crop (timing and way of destroying cover crop)

Summer cover crops to follow wheat CERES TRUST Grant

Transition strategies for going from conventional to organic grain crop production

Organic Vegetable Production and Soil Health

CORN/SOYBEAN/WHEAT ROTATION

Treatments of the study are:

4 Compost rates in subplots, based on crop P needs Plots are: No-till with

cover crop, Tilled with cover crop, Tilled without cover crop

Photos taken June 22, 2012, DOP May 21

COMPOST APPLICATON BASED UPON P

Compost:3-2-2 Wheat P Recommendation-80 lb P205/acre Corn P Recommendation- 120 lb P205/acre Soybean P Recomendaton-90 lb P205/acre Wheat P Treatments: 0, 40, 80, and 120

lb P205/acre Wheat Compost Application Rates:

0, 1333, 2666, and 4000 lb Compost/acre

0 lbs/acre 2105 lbs/acre

4210 lbs/acre

6315 lbs/acre

0

10

20

30

40

50

602012 Wheat Yield

Compost Rate

Bu

sh

els

/acre

2105 lbs compost contains 40 lbs P and 59 lbs N4210 lbs compost contains 80 lbs P and 117 lbs N6315 lbs compost contains 120 lbs P and 176 lbs N

COVER CROP YIELD

6704 lb/acre 6989 lb/acre

ROLLING/CRIMPING THE COVER CROP

Treatment Depth (inches) Soil Moisture (%)

Rye cover crop 0 to 2 17

2 to 6 19

6 to 10 19

No cover crop 0 to 2 12

2 to 6 16

6 to 10 25

Soil moisture in cover crop and no cover crop plants on May 16, 2012 (one day before corn planted, 15 days after last rain)

Field capacity is approximately 34% and the wilting point is approximately 18 % soil moisture.Conclusion- cover crops conserved moisture in seed zone but depleted deeper soil moisture.

ORGANIC PRODUCTION-COLLECTING CO2 AND N2O SAMPLES

SOIL MOISTURE RETENTION BY COVER CROPS IN CORN

DAR= days after rain (irrigation)

SOIL MOISTURE RETENTION BY COVER CROPS IN SOYBEAN

DAR= days after rain (irrigation)

SOYBEANS ON JULY 16… All look about the same

Till, no cover crop Till, with cover crop

No-till, with cover crop

Weed control1 cultivation in tilled soybeans and corn, 2 minor hoeings in all plots. Weeds are being held back well by cover crop and drought.

This alley area has had no weed control other than rolled cover crop

CORN NOT THE SAME STORYJUNE 22, 2012

No-till with cover crop

Tilled, no cover crop

Tilled, with cover crop

JULY 16, 2012

Tilled, no cover crop Tilled, with cover crop

no-till tilled + cc tilled no cc0

5

10

15

20

25

30

35

40

45

50

2012 Soybean Yield

Tillage Type

Bu

shels

/acr

e

0 lbs P/ac 45 lbs P/ac 90 lbs P/ac 135 lbs P/ac33.0

34.0

35.0

36.0

37.0

38.0

39.0

40.0

41.0

42.0

43.0

2012 Soybean Yield

Compost Rate

Bu

sh

els

/acre

no-till tilled + cc tilled no cc0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

2012 Corn Yield

Tillage Type

Bu

sh

els

/acre

0 lbs N/ac 90 lbs N/ac 180 lbs N/ac 270 lbs N/ac0

10

20

30

40

50

60

70

80

90

2012 Corn Yield

Compost rate

Bu

sh

els

/acre

MEASURE SOIL QUALITY-ACTIVE CARBON

PLANTING CORN INTO A COVER CROP (RYE+HAIRY VETCH) IN A NO-TILL FIELD

How should cover crop be destroyed?Rolling or Chopping

When should corn be planted?Before or after cover crop destructionPlanted into standing cover cropDestroyed and planted same dayPlanted 1 week after destructionPlanted 2 weeks after destruction

DESICCATION OF THE COVER CROPROLLER CRIMPER

FLAIL MOWING

PLANTING INTO A STANDING CROP

TO ROLL OR FLAIL CHOP

DAY OF DESICCATION 5 DAYS LATER

Flailed Rolled Rolled Flailed

WHAT IF THE COVER CROP IS STILL ALIVE?

PLANT PERPENDICULAR TO THE WAY IT WAS ROLLED

SEED TO SOIL CONTACT CAN BE A CHALLENGE

chop roll chop roll chop roll chop rollbefore cc destroyed

same day cc destroyed

1 week after cc destroyed

2 weeks after cc destroyed

0

10

20

30

40

50

60

70

80

90

100

Corn germination when planted into rye cover crop

Pla

nt

co

un

t p

er

10

fe

et

SUMMER COVER CROPS TO FOLLOW WHEAT

Why let your field build up its weed bank like these plots with no cover crop planted?

Get weed reduction and improved soil organic matter with summer cover crops like buckwheat and sorghum-sudangrass. These plots had no herbicide and are all no-till

Follow wheat with a legume summer cover crop, such as cowpea, which will fix nitrogen. If followed up with a winter cover crop, that nitrogen will continue to be available for your crop the following summer.

Weedy plot with no cover crop

Cowpea

Sorghum sudangrass is very effective at controlling weeds and contains chemicals that can persist in the soil and continue to control weeds in the following season. Best to follow with soybeans.

Sorghum sudangrass

Weedy plot with no cover crop

Sunn hemp and sesbania are two other nitrogen fixing summer cover crops. Seed costs are a little higher than for other summer cover crops. If government programs continue to encourage cover crop usage, the market for cover crop seed will increase and prices may lower. Local production of cover crop seed should also be considered.

Sunn hemp

sesbania

buck

whe

at

cowpe

as

sesb

ania

sorg

hum

-sud

angr

ass

sunn

hem

p

turn

ip

win

ter ra

dish

0

5000

10000

15000

20000

25000

Summer Cover Crop Yields

Crop Species

Pounds/a

cre o

f dry

matt

er

pro

duce

d

buckwheat

cowpeas fallow sesbania ss sunn hemp

turnip winter radish

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Percentage of weed cover

CERES FOUNDATION

Transitioning to Organic

Weed Control number one problem

Soil Quality Build up

Strategies

STRATEGIES FOR TRANSITIONING

Cash Crop All Three Years?

Weed Control Strategies

Tillage vs No-Tillage

TREATMENTS

Always use a polyculture cover crop-legumes, grasses, and brassicas

Treatment 1: always use a crop that is mowed or incorporated into the soil-no cash crop-includes sorghum x sudangrass (SXS)

TREATMENTS

Treatment 2-cover crops first year (SXS): cash crops 2nd (grain sorghum) and 3rd years.

Treatments 3 and 4: no-till-soybean/grain sorghum or soybean/corn rotation

Treatments 5 and 6-same as treatments 3 and 4 except tilled

Treatment 7: tilled sorghum x sudan first year followed by wheat/soybean/corn

WHY SORGHUM?

Allelopathic Chemicals released

from roots that inhibit weed germination

No GMO’s Sorghum Bicolor is

also shattercane!

Transitional system 2012 cropCrop

Height (in)

Stand count/10

feet

Weed dry

matter (lbs/acre)

Crop dry matter

(lbs/acre)

Soybean grain yield

(bu/acre)No-till w/ summer cover crop

sorghum-sudangrass 65 78 2591 4879  

Conventional till soybean 34 51 1662 2589 44.7No-till soybean 20 40 1849 684 5.9

2012 Ceres Trust Study

ORGANIC VEGETABLE PRODUCTION

ORGANIC VEGETABLE PRODUCTION-SOIL HEALTH

QUESTIONS?