Integrating Cover Crops into Specialty

Crops Production

Cary L. Rivard, Ph.D.

Dept of Horticulture

Kansas State University

Overview

Cover Crops for Vegetable Production

• Benefits of cover crops

• Challenges

• Tools

• Cover Crops for KS

• High Tunnels

• No-till Research

Cover Crops

• Also known a “green manures”, cover crops are extremely important for soil health – Organic matter – Soil microbial health

• Suppress Weeds

• Add / Recover nitrogen – Highly-leachable N03

– Legume cover crops fix N

• Can be used as mulch – No-till or strip-tillage

• Can reduce excess nutrients (P)

• Reduce soil erosion

Cover Crops Have Numerous Benefits

Nitrogen Recovery / Deposition

Benefits of Cover Crops

• NO3 Recovery

• Legume cover crops

• Calculated lbs/A N

– Legumes

• 3.5-4% (young tissue)

• 3-3.5% (flowering)

– Grasses

• 2-3% (young tissue)

• 1.5-2.5% (flowering)

Lbs biomass

Estimated % N

50% Availability

Total Nitrogen

x

x =

Biomass (lbs/acre) C:N

Available N

Rye Vetch (lbs/acre)

High Tunnel 3749.4 329.4 9.8 83.2

Field 721.8 1589.1 8.5 54.2

Benefits of Cover Crops

Tillage releases soil carbon

Reduced Weed Seed Bank

Benefits of Cover Crops

• Weed seed germination

– Light

– Soil disturbance

• Cover crops

– Competition

• Life cycle interruption

– Reduced seed bank

Grow Your Own Mulch

Benefits of Cover Crops

• Cover crop residues serve as mulch – Weed management

– Soil moisture

– Crop health and quality

• Source of soil carbon

• Source of nitrogen

• “Low Risk”

Utilize Cover Crops to Attract Beneficials and Pollinators

Clover Cover Crop used as “living mulch”

Annual Rye in Row Middles (Fall-Spring)

Cover Crop used as wind breaks

Challenges exist with cover crops

Challenges of Cover Crops

• Managing cover crop biomass

• Equipment

• Disease and pest pressure

• Production logistics

– Have a CC plan!

Southern Blight on Tomato

Re-growth

Managing Cover Crop Biomass Can be a Challenge

Planning for Cover Crops

Taken from: The New Organic Grower, Eliot Coleman

Planning for Cover Crops

Winter CC

Winter CC Cash (Vegetable) Crops

Fall Cash Crops Fall Cash Crops Summer Cover Crops

Fall CC Winter CC Cash (short) Crops

Winter CC

A few scenarios for planning your rotation

• Warm-Season Vegetables

• Cool-Season Vegetables

• Fall Cover Crops

Tools Required for Cover Crops

• Overhead Irrigation – Aluminum solid set – “Big Gun” sprinkler

• Managing cover crops – Scythe – Pole trimmer (small) – Flail mower – Roller crimper (large) – Herbicides ??

Getting Started

Perfecta II Field Cultivator

Video

Annual Grasses - Rye, Wheat, Oats, etc.

• High biomass – Rye is highest – Straw production

• Nitrogen recovery

• Weed competition – Allelopathy (Rye)

• Killing the crop – Early crops

• Plant Sept 1 – Nov 15

Winter Cover Crops

Crop Winter Rye

Winter Cover Crops

Oats Winter Wheat

Annual Legumes

Winter Cover Crops

• Fix Nitrogen

– Inoculant

• Clovers

• Vetch

• Winter peas

• Easier to kill

• Less biomass (straw)

Crimson Clover (Annual)

Winter Cover Crops

Austrian Winter Pea Hairy Vetch

Tillage Radish

Fall Cover Crops Tillage Radish and Other Brassicas

Annual Grasses – Sorghum, Millet, Spring Oats

• High Biomass – Nitrogen recovery

– Weed competition

– Mulch / OM production

• Short duration – Millet (45 days)

• Can be particularly difficult to kill – Sorghum-Sudan

Summer Cover Crops

Foxtail Millet

Summer Cover Crops

Sorghum-Sudan Grass Japanese Millet

Annual Summer Legumes

• Fix Nitrogen – Inoculant

• Soybean

• Forage soybean – Biomass

• Berseem Clover – Pollinators

• Cowpea – Very drought tolerant

Cowpeas

Summer Cover Crops

Summer Cover Crops

Berseem Clover Forage Soybeans

Other Annual Summer Cover Crops

Summer Cover Crops

Buckwheat Sunn Hemp

Cover Crops in Tunnels

Cover Crops are important in high tunnels

• Need to retain soil quality

• Challenges

– Irrigation

– Real Estate

• “Short-window” crops

• Mowing down the crop

• Moveable tunnels

• Benefit to soil:

• Microbial health and structure

• Weed seed bank

• Carbon / organic Matter

• Benefit to crops:

• Better yield and stability

• N fertilizer

• Weed management

• Have a management plan for cover crops

Summary Cover Crops benefit the soil and the farm

No-Till Pumpkin Research Evaluation of cover crops for NT Pumpkins

• C.L. Rivard, M. Kennelly, J. Griffin

• John C. Pair Hort. Center – Richard Ryer

• KCSAAC Grant

• Spring Cover Crops

Spring Cover Crops

B

B B

B

B

A A

Planting in Cover Crop Residue

Harvesting Pumpkins at JCP

C

BC

AB AB

AB

AB

A

AB

No-Till NRCS CIG Project NRCS Conservation Innovation Grant Program

• Rivard, C.L., M. Kennelly, J. Griffin, R. Janke, D. Presley, P. Tomlinson, R. Wynia (NRCS), M. Bates (MU)

• Demonstrate no-till systems – Pumpkin, sweet corn, snap bean – Equipment (planter) experience

• 4 replicated trials at KSU/NRCS locations

• 16 demonstration trials at commercial farms (2014-15)

30’

60’

280’

5’

= 1 - Conventional Tillage

= 2 – Winter Rye

= 3 – Winter Rye / Pea

= 4 – Winter Rye / Hairy Vetch

= 5 – Winter Rye / Tillage Radish

= 6 – Rye / Vetch / Radish

= 7 – Spring Oats

= 8 – Spring Oats / Pea

50’ 60’

30’

Not to scale. Each plot will contain three (50’) rows.

Soil Quality Data Collection

9’

Planting Spring CC at Olathe

Roller Crimper Video

Winter CC at Wichita

Spring Oats in Manhattan

Planting Beans and Corn

A

BC

AB A

36.7

A

D

D

0

10

20

30

40

50

60

70

80

90

100

Conv. Tillage

Winter Rye

Rye / Pea

Rye / Vetch

Rye / Raddish

Rye / Vetch / Raddish

Spring Oats

Oats / Pea

Pe

rce

nt

We

ed

Co

vera

ge (

%)

2013 No-Till Pumpkin Trials

Wichita

Olathe

CD BCD

BC

D

BCD BCD

A

B

0

200

400

600

800

1000

1200

1400

1600

1800

Conv. Tillage

Winter Rye

Rye / Pea

Rye / Vetch

Rye / Raddish

Rye / Vetch / Raddish

Spring Oats

Oats / Pea

Tota

l Est

imat

ed

Fru

it Y

ield

(lb

s/p

lot)

2013 No-Till Pumpkin Trial at JCP Center

D

BCD BCD

CD

BCD

BC

A

AB

0

10

20

30

40

50

60

70

80

90

Conv. Tillage

Winter Rye

Rye / Pea

Rye / Vetch

Rye / Raddish

Rye / Vetch / Raddish

Spring Oats

Oats / Pea

Ave

rage

Fru

it N

um

be

r (#

/plo

t)

2013 No-Till Pumpkin Trial at JCP Center

B

B B

B

B

B

A

B

0

10

20

30

40

50

60

70

80

90

Conv. Tillage

Winter Rye

Rye / Pea

Rye / Vetch

Rye / Raddish

Rye / Vetch / Raddish

Spring Oats

Oats / Pea

Ave

rage

Fru

it W

eig

ht

(lb

s/fr

uit

) 2013 No-Till Pumpkin Trial at JCP Center

• Cover crop selection and cultivation is very important

• The jury is still out on spring cover crops

• Hairy vetch can be hard on planters

• Nitrogen management is a critical component to successful NT systems

Preliminary Conclusions No-Till Pumpkins in Kansas

QUESTIONS ??