NITROGEN PRODUCTION AND NUTRIENT SEQUESTRATION

Nitrogen Benefit

Biological Nitrogen Fixation

Timing of Hairy Vetch Harvest and Corn Yield

Adapted from Gallagher, Penn State

2007 Hairy Vetch Corn Yield-0 NTime lbs/acre %N N lbs/acreEarly (May 4) 1,400 3.82 55 113Middle (May 15) 4,300 4.43 190 132Late (May 31) 6,600 4.15 274 140

2008Early (May 1) 3,204 2.49 80 92Middle (May 14) 4,005 2.92 117 121Late (May 29) 4,361 4.55 197 79

Growth Stage Will Make a Difference

1500-2000 lbs/acre 4-5,000 lbs/acre

N Release over Time From Cover Crops in North Carolina

2 4 8 12 160

10

20

30

40

50

60

70

80

90

100

Rye

Crimson Clover

Hairy Vetch

From Wagger, 1989. Agronomy Journal

lbs/

acr

e

Weeks

% N Remaining Over Time

From Wagger, 1989, Agronomy Journal

Harvest Time on N and C:N Ratio

Cover Crop Harvest Time Dry Wt N ConcentrationTotal N C:Nlbs/acre % lbs/acre

Rye Early 6355 1.49 94 27:1Rye Late 8144 1.25 101 32:1Crimson Clover Early 3827 2.76 106 14:1Crimson Clover Late 5260 2.48 131 16:1Hairy Vetch Early 3720 3.69 131 11:1Hairy Vetch Late 6337 3.22 204 12:1

From Wagger, 1989. Agronomy Journal

Corn Yield From Kentucky

0 50 1000

20

40

60

80

100

120

140

160

Hairy Vetch Crimson Clover

Rye Control

187 lb N/acre

50 lb N/acre

36 lb N/acre

From Ebelhar et al, 1986

Missouri Data-Bradford 1990’s

Corn Grain Sorghum

Species Seed Rate Dry Matter N Equivalent N Equivalent   lbs/acre lb/acre lb/acre

lb/acre Hairy Vetch 30 1744 37.3 54.8 20 1451 40.2 46.5 Austrian Winter Pea 60 712 26.4 35.1 40 757 33.6 6.5

From Reinbott, et al, 2004 Agronomy Journal

2013 Corn Yield After Cover Crops

Corn Yield 2013 Cover Crops Overseeded into Soybean September 2012 Corn Treatment Yield Bu/acre Control 175 Hairy Vetch 199 Crimson Clover 165 Radish 174 Cereal Rye 175 Hairy Vetch+Rye 187 Crimson Clv. +Rye 181 Radish + Rye 173 Rye+Radish+HV+CC 174

Reinbott, 2013

Not As Much Yield Advantage As It Looked

Results From Using Cover Crops

7 more Bushels/acre

Seed Cost-$45/acre

7 bushel/acre @ $13/bushel=$91/acre

Or about $46/acre profit

2013 Soybean Yield After Cover Crops

Soybean Yield 2013 Cover Crops Overseeded into Corn Sept. 2012 Treatment Yield Bu/acre Control 29 Hairy Vetch 24 Crimson Clover 28 Radish 27 Cereal Rye 36 Hairy Vetch+Rye 28 Crimson Clv. +Rye 33 Radish + Rye 29 Rye+Radish+HV+CC 27

Reinbott, 2013

WHAT OTHER BENEFITS DO RYE, RYEGRASS, AND TILLAGE RADISH HAVE?

Nutrient Scavenge, Loosen Soil, Weed Control

Tillage Radish Root dug out-32”Courtesy of Steve Groff-Pennsylvania

TillageRadish®

field

Openfield

Soil compactiondecreased by >40%

Ohio State UniversityCourtesy of Steve Groff

Loosen Soil-Increase root growth and water infiltration?

Less Compaction Equals More Root Density Deeper Following Radish and Rye

Gruver, et al, 2012

Soybean Roots Follow Cover Crop Root Channels

Williams and Weil, 2004

NUTRIENT SEQUESTRATION

Percent Total Available P and K at Different Depths in the Soil Profile-Silt

Loam-Silty Clay Loam

P K0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

36 to 4829 to 3624 to 2918 to 2412 to 189 to 123 to 90 to 3

Clark and Reinbott, 2012

0

6

12

18

24

30

36

42

48

0 20 40 60 80 100 120 140 160

Soil Nutrients, lb per acre

So

il d

ep

th, in

ch

es

P & K build up on Sands

N P KCourtesy of David Dunn, 2013

N P K

Soil Potassium Levels After Three Years of Cover Crops

0 to 3 3 to 6 6 to 120

20

40

60

80

100

120

140

noneRyeCrimson CloverHairy Vetch

lb K

/acr

e

Hargrove et al, 1986

Increase in Soil Test P Around Tillage Radish Roots by 2X

1.25 inch

2 inches

White and Weil, 2011

Nitrogen Capture By Tillage Radish

-10

10

30

50

70

90

110

130

150

Shoot

RootCornCorn

Soybean

Soybean

Lbs/

acr

e

Dean and Weil, J Eniv. Quality 2009

Radish and Rye Capture Nitrate-N in the Soil Profile

NOT ALWAYS POSITIVE

Cotton Lint and Seed Yield Decreases Following a Rye or Wheat Cover Crop

Lint Seed Wheat Rye ControlWheat Rye Control

Cotton 886 854 1129 1368 1333 1831

lb/acre

Li, et al, Agronomy Journal 2013

WHAT ABOUT WATER?Infiltration, Run-off, Conservation

From Steve Groff

Cover Crop No Cover Crop

Cover Crops Reduce Water Runoff or Increase Water

Infiltration

Water From Tilled (left), No-Till (middle) and No-Till With Cover Crop (right)

QUESTIONS?