Managing Cover Crops for More Profitable Corn

Production

Brian JonesAgronomy Extension Agent

(540)245-5750brjones8@vt.edu

http://www.valleycrops.cses.vt.edu

Are we facing uncertainty?

“There are two kinds of

economists making

forecasts these days, those who don’t know and those who don’t know they don’t

know”

50

100

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1995

July

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1990

-199

2 =

100

Source: National Agricultural Statistics Service, USDA.

Fertilizer prices: 1995 - 2008

Efficient Nutrient Use is Essential for Profitability and Sustainability

Efficiency…Through cover crops? Name of the game now more than ever How can cover crops help our growers be more

efficient? By closing the holes in the system

Especially important for our no-till systems Facilitate the “rehab from our

tillage addictions”

NO-TILL

CULTURAL

BIOLOGICAL

ENVIRONMENTAL

Nutrient MgtSoil Health

Residue MgtCover Crops

Pest MgtEquipmentRotations

NO-TILL

CULTURAL

BIOLOGICAL

ENVIRONMENTAL

Nutrient MgtSoil Health

Residue MgtCover Crops

Pest MgtEquipmentRotations

Many Benefits of Cover Crops

ENHANCE NUTRIENT CYCLING

INCREASE INFILTRATION

REDUCE COMPACTION

IMPROVE SOIL STRUCTURE

INCREASE ORGANIC MATTER

REDUCE SOIL EROSION

WEED SUPPRESSION

Nutrient Cycling“The movement of nutrients through an ecosystem”

Holes:• Leaching• Immobilization• Volatilization• De-nitrification

Plugs:• Scavenging• N Fixation• OM creation• Increase crop yield

Challenges of Cover Crops Fitting them into your system

Livestock producers: Have to have the feed…

Cash grain producers: Getting cover crops in the ground

Nutrient cycling How much N? May be variable and will need to

test (PSNT) N tie up with high C:N cover crops

Rye killed late May not see N until following year

Challenges of Cover Crops Cropping challenges

Allelopathy may affect cash crop Stand / emergence issues Planting equipment adjustments Mechanically killing for some Good environment for harmful insects Cost of production

Challenges of Cover Crops Need to understand these questions with

local systems and conditions No perfect cover

Depends on rotation, needs, etc. Need local research…

Two ongoing cover-crop projects Rockingham County (Brian Jones) New Kent County (Paul Davis)

ObjectivesRockingham:– Quantify the effects of cover crop species

and timing of termination on nutrient cycling and yield

New Kent:– Determine the effects of cover crop

species, starter fertilizer and side-dress N rates on nutrient cycling and yield

Methods - Rockingham Planted in fall of 2006 in Rockingham County Planted six different cover crop treatments:

Rye (120 lb) Crimson clover (20 lb) Hairy vetch (25 lb) Rye (90 lb) + hairy vetch (25 lb) Rye (60 lb) + crimson clover (10 lb) + hairy vetch (10 lb) Rye (90 lb) + daicon radish (15 lb)

Three replications of each Two cover crop termination dates: May 10 (boot stage rye)

and June 1 (soft dough) 0 lbs N applied to corn

Daicon Radish

Not a traditional radish Being marketed as biological compaction relief Some evidence of increased microbiological

activity as a cover crop

Methods – New Kent Planted on Nov 1, 2007 in New Kent Planted three different cover crop treatments:

Rye (90 lb) Rye (56 lb) + hairy vetch (10 lb) Hairy vetch (25 lb)

Starter (40 lb) or no starter Five injected side-dress rates (0, 40, 80, 120, 160

lb N) Four replications of each Cover killed on May 1

Methods At both sites:

Cover crop biomass, plant tissue samples and soil samples taken

Corn planted no-till following termination Rockingham: corn silage harvested with

forage chopper and weighed New Kent: corn grain hand harvested and

weighed

Cover Crop Biomass - RHCover Crop Yield at Two Kill Dates

0.00

2.00

4.00

6.00

8.00

10.00

12.00

Rye

Crimso

n Clo

ver

Vetch

Rye/V

etch

Rye/V

etch/C

lover

Rye/R

adish

Check

Cover Crop Species

Yie

ld (

ton

ac-

1)

10-May

1-Jun

Cover Crop Biomass – NK 2007

LSD = 2.1

0

1

2

3

4

5 6

7

8

Ear

ly

Mid

Late

Ear

ly

Mid

Late

Ear

ly

Mid

Late

Ear

ly

Mid

Late

Ear

ly

Mid

Late

Ear

ly

Mid

Late

Ear

ly

Mid

Late

Barley CrimsonClover

Oats Rye Rye + Vetch

Vetch Triticale

Bio

mas

s Y

ield

, to

ns

/ac

Total N from Cover Crop - RH

Plant Nitrogen at Two Kill Dates

0.00

50.00

100.00

150.00

200.00

250.00

300.00

350.00

Rye

Crimso

n Clo

ver

Vetch

Rye/V

etch

Rye/V

etch/C

lover

Rye/R

adish

Check

Cover Crop Species

Pla

nt

Nit

rog

en (

lb a

c-1)

10-May

1-Juna a

aa

a

a

Total N from Cover Crop – NK 07

LSD = 22

0

50

100

150

200

250

300

350

Ear

ly

Mid

Late

Ear

ly

Mid

Late

Ear

ly

Mid

Late

Ear

ly

Mid

Late

Ear

ly

Mid

Late

Ear

ly

Mid

Late

Ear

ly

Mid

Late

N u

pta

ke,

lbs/

ac

Barley CrimsonClover

Oats Rye Rye + Vetch

Vetch Triticale

Available N From Cover - RH Total N is not all available for mineralization

and crop uptake Loss factors include:

Volatilization (loss to atmosphere) Immobilization (tied up by bacteria) Leaching (loss to groundwater)

Available N From Cover - RH Volatilization losses

Depend largely on whether or not cover was incorporated

Without incorporating cover crop in our climate figure approximately 50% loss due to volatilization

Species10-May 1-Jun

Rye 43.7 47.9Crimson Clover 85.3 * 119.7 *Hairy Vetch 63.1 145.8 *Rye/Vetch 107.5 * 88.7Rey/Vetch/Clover 86.3 * 124.8 *Rye/Radish 68.1 62.9None 23.6 44.3

Potentially Available N (lb/ac)

Available N From Cover - RH Immobilization losses

Depend largely on the carbon to nitrogen ratio (C:N) of the cover crop species

Low C:N (<25) bacteria quickly break down vegetation making N available immediately

High C:N (>25) N will become available, but may not be until the following growing season

Also, bacteria will tie up soil N in order to digest high carbon residue

Often see this with the yellowing of corn in early spring with high residue

Cover Crop C:N at Two Kill Dates

0.00

10.00

20.00

30.00

40.00

50.00

60.00

70.00

80.00

Rye

Crimso

n Clov

er

Vetch

Rye/V

etch

Rye/V

etch

/Clo

ver

Rye/R

adish

Check

Cover Crop Species

C:N

Available N From Cover - RH

Net Loss of PANfrom immobilization

Net gain of PANfrom mineralization

Available N From Cover - RH

SpeciesPotentially

Available N (lb/ac) C:NAvailable N (lb/ac)

10-MayRye 43.7 31.76 ?Crimson Clover 85.3 14.55 85.3Hairy Vetch 63.1 11.68 63.1Rye/Vetch 107.5 18.27 107.5Rey/Vetch/Clover 86.3 23.81 ?Rye/Radish 68.1 43.85 ?None 23.6 28.89 ?

1-JunRye 47.9 45.71 ?Crimson Clover 119.7 20.45 119.7Hairy Vetch 145.8 13.07 145.8Rye/Vetch 88.7 39.71 ?Rey/Vetch/Clover 124.8 37.89 ?Rye/Radish 62.9 75.34 ?None 44.3 36.69 ?

Available Soil N - RH Sampled the NO3-N and NH3-N fraction at

corn planting to see how much was potentially available These are highly mobile Most of crop uptake

Available Soil N - RHAvailable Soil N at Two Kill Dates

0.005.00

10.0015.0020.0025.0030.0035.0040.0045.0050.00

Rye

Crimso

n Clo

ver

Vetch

Rye/V

etch

Rye/V

etch/C

lover

Rye/R

adish

Check

Cover Crop Species

Ava

ilab

le N

(lb

s ac

-1)

10-May

1-Jun

Available Soil N - RH

Species

Available N (lb/ac) from

Residue

Available Soil N (lb/ac)

Total PAN (lb/ac)

10-MayRye ? 32.5 ?Crimson Clover 85.3 23.3 108.6Hairy Vetch 63.1 23.9 87.1Rye/Vetch 107.5 45.4 152.9Rey/Vetch/Clover ? 43.9 ?Rye/Radish ? 40.0 ?None ? 16.3 ?

1-JunRye ? 19.9 ?Crimson Clover 119.7 30.5 150.2Hairy Vetch 145.8 45.5 191.3Rye/Vetch ? 39.0 ?Rey/Vetch/Clover ? 15.3 ?Rye/Radish ? 29.5 ?None ? 19.7 ?

QUESTIONS?

Crop Response So how much N was actually available to the

corn crop from our cover crop treatments? Best observed by looking at the plant itself

Ear leaf samples show the % N in the plant at silking and provide a good “in-season” analysis of N uptake

Crop Response – Ear Leaf N @ RH

Corn Ear Leaf N from First Kill Date

0.00

0.50

1.00

1.50

2.00

2.50

3.00

Rye

Crimso

n Clo

ver

Vetch

Rye/V

etch

Rye/V

etch/C

lover

Rye/R

adish

Check

Cover Crop Species

% N

in

Ear

Lea

f

a a a

Crop Response – Ear Leaf N @ NK

No Starter

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

0 40 80 120 160

Sidedress N Rate, lb ac-1

Ear

Leaf

N, %

Rye+Vetch

Rye

Vetch

Crop Response – Silage Yield

Corn Silage Yield at Two Kill Dates

0.002.004.006.008.00

10.0012.0014.0016.00

Rye

Crimso

n Clov

er

Vetch

Rye/V

etch

Rye/V

etch

/Clov

er

Rye/R

adish

Check

Cover Crop Species

Co

rn S

ilag

e Y

ield

(to

n a

c-1

)

10-May

1-Jun

a a a a

Crop Response – Grain Yield

y = -0.0019x2 + 0.8963x + 53.565

R2 = 0.9867

y = -0.0016x2 + 0.8023x + 72.317

R2 = 0.9929y = 0.0612x + 144.83

R2 = 0.1819

0

20

40

60

80

100

120

140

160

180

200

0 50 100 150 200

Sidedress N Rate, lb ac-1

Gra

in Y

ield

, bu

ac-1

Rye+Vetch, no Starter

Rye, no Starter

Vetch, no Starter

Summary - Rockingham Cover crops provided from 32 to 152 lb of PAN to

the corn Delaying cover crop termination increased PAN

by as much as 80 lbs for legume covers, but reduced PAN for small grains (greater C:N) Adversely affected corn yield in 2007 (drought)

Radish+rye increased both rye biomass and corn yield above rye alone Greater water use efficiency? Microbiological effect?

Summary – New Kent No response observed in grain yield

following vetch from 0 to 160 lbs side-dress N

Corn following rye and rye+vetch responded to side-dress N Higher C:N ratios Tied up available N

QUESTIONS?

Economics Bottom line: Seed and establishment not

cheap Hard sell looking at just seed costs

Cover Crop Variety

Wheat VNS4 19.00$ bu 2 bu/ac 15.86$ ac 53.86$ ac 35.00$ ac 20.00$ ac (18.86)$ ac (33.86)$ ac

Rye Graze Master 16.00$ bu 2 bu/ac 15.86$ ac 47.86$ ac 40.00$ ac 25.00$ ac (7.86)$ ac (22.86)$ ac

Wheeler 17.75$ bu 2 bu/ac 15.86$ ac 51.36$ ac 40.00$ ac 25.00$ ac (11.36)$ ac (26.36)$ ac

Huron 18.50$ bu 2 bu/ac 15.86$ ac 52.86$ ac 35.00$ ac 20.00$ ac (17.86)$ ac (32.86)$ ac

Abruzzi 16.25$ bu 2 bu/ac 15.86$ ac 48.36$ ac 40.00$ ac 25.00$ ac (8.36)$ ac (23.36)$ ac

Barley Nomini 10.88$ bu 2 bu/ac 15.86$ ac 37.62$ ac 35.00$ ac 20.00$ ac (2.62)$ ac (17.62)$ ac

Thoroughbred 11.25$ bu 2 bu/ac 15.86$ ac 38.36$ ac 35.00$ ac 20.00$ ac (3.36)$ ac (18.36)$ ac

Triticale VNS 24.25$ bu 2 bu/ac 15.86$ ac 64.36$ ac 35.00$ ac 20.00$ ac (29.36)$ ac (44.36)$ ac

Crimson VNS 2.11$ lb 20 lb/ac 15.86$ ac 58.06$ ac 25.00$ ac 25.00$ ac (33.06)$ ac (33.06)$ ac

Vetch Common 1.04$ lb 20 lb/ac 15.86$ ac 36.66$ ac 25.00$ ac 25.00$ ac (11.66)$ ac (11.66)$ ac

Notes1. Average price taken from a seed dealer survey on August 132. Seeding rates based on requirements in the 2009 BMP manual3. Seeding cost based on the 2007 VCE farm custom rate survey4. VNS = variety not stated.

After Oct 5

Producer Costs for Cover Crop Establishment

Establishment Costs

Before Oct 5 After Oct 5

Cost ShareAverage

Price1

Seeding

Rate2

Seeding

Cost3

Before Oct 5

Economics – Yield Advantage @ RH

Cover Crop1 Variety2Seeding

Rate

Seed

Cost3Establishment

Cost4Corn Silage Yield

@ 35 DM

Value of Corn

Silage5Return over

Establishment Costslb ac-1 tons ac-1

Rye Wheeler 120 35.50$ 51.36$ 8.98 269.52$ 218.16$ Crimson Clover VNS 20 42.20$ 58.06$ 13.79 * 413.82$ 355.76$

Hairy Vetch VNS 20 20.80$ 36.66$ 13.79 * 413.82$ 377.16$ Rye/Vetch Wheeler/VNS 90/25 52.63$ 68.49$ 10.62 318.53$ 250.04$

Rye/Vetch/Clover Wheeler/VNS/VNS 60/10/10 49.25$ 65.11$ 14.52 * 435.60$ 370.49$ Rye/Radish Wheeler/VNS 90/15 67.13$ 82.99$ 12.98 * 389.32$ 306.33$ No Cover 0 -$ -$ 5.99 179.69$ 179.69$

------------------$ ac-1---------------- ------------------$ ac-1----------------

Economics – N Advantage @ RH

Cover Crop1 Variety2

Total PAN Available from

Residue3

Adjusted PAN Available from

Residue4

PAN from Soil

NO3 and Soil NH3

Estimated PAN for Corn

Silage Crop5Value of N Returned

(@ 0.90 N)$ ac-1

Rye Wheeler 87.48 0.00 32.45 * 32.45 29.21$ Crimson Clover VNS 170.55 * 85.27 23.31 * 108.58 97.72$

Hairy Vetch VNS 126.22 63.11 23.94 * 87.05 78.35$ Rye/Vetch Wheeler/VNS 215.06 * 107.53 45.36 * 152.89 137.60$

Rye/Vetch/Clover Wheeler/VNS/VNS 172.53 * 86.26 43.88 * 130.15 117.13$ Rye/Radish Wheeler/VNS 136.14 0.00 39.96 * 39.96 35.97$ No Cover 0.00 0.00 16.29 16.29 14.66$

--------------------------------------------------------lb ac-1 -----------------------------------------------

Economics – $ Advantage @ RH

Cover Crop1 Variety2

Corn Silage Value after Establishment

CostsValue of N Returned

(@ 0.90 N)

Total Short-Term Dollar

Value3

Rye Wheeler 218.16$ 29.21$ 247.37$ Crimson Clover VNS 355.76$ 97.72$ 453.48$

Hairy Vetch VNS 377.16$ 78.35$ 455.51$ Rye/Vetch Wheeler/VNS 250.04$ 137.60$ 387.64$

Rye/Vetch/Clover Wheeler/VNS/VNS 370.49$ 117.13$ 487.62$ Rye/Radish Wheeler/VNS 306.33$ 35.97$ 342.29$ No Cover 179.69$ 14.66$ 194.34$

----------------------------------------$ ac-1---------------------------------------

Plant Growth and Plant Nutrition are Complex!

“Providing adequate plant nutrients to growing crops is not rocket science, it is a lot more complex!” – Dr. Jerry Hatfield, National Soil Tilth Lab, USDA- Ames Iowa.

The Virginia No-Till Alliance We (advisors) must have answers to grower’s

questions as they face these challenges Formation of the Virginia No-Tillage Alliance

organization

THANK YOU

THOUGHTS OR QUESTIONS?