Presented at the Horticulture Industries Show in Tulsa, OK, Friday Jan. 5th This presentation will cover the benefits and applications of cover crops in farming systems. Cover crop species adapted to the mid-south will be discussed with management notes and considerations including weed control, disease suppression, nitrogen fixation, and building soil organic matter. Equipment for planting, terminating and managing cover crop residue will be discussed for various scales of operations. In addition, techniques for measuring and assessing cover crop performance will be discussed along with the economic benefits of including cover crops in a production system. Presenter: Luke Freeman is a Horticulture Specialist for the National Center for Appropriate Technology (NCAT) and covers small fruit and vegetable production, cover crops and produce safety for the ATTRA Sustainable Agriculture project. Luke has his M.S. from the University of Arkansas where he studied cover crop applications in high tunnels and worked on the high tunnel berry project and the National Strawberry Sustainability Initiative under Dr. Curt Rom. Luke and his wife Natalie live on a small farm outside of Fayetteville where they raise laying hens, goats, vegetables and cut flowers.

1. Horticulture Industries Show
January 5th, 2018
Cover Cropping
for Regenerative
Agriculture
Presenter Luke Freeman
Horticulture Specialist, NCAT/ATTRA

2. 1. Introduction
2. Benefits of cover cropping
3. Cover crop species
4. Management considerations
5. Economics of cover cropping
Outline
2

3. Regenerative Agriculture?
3
• Regenerate topsoil and increase biodiversity
• Improve water cycles
• Enhance ecosystem services
• Increase resilience to climate fluctuation
• Strengthen the health and vitality of farming
communities

4. What are cover crops?
4
• Grown for the benefit of the soil
• Mowed, tilled, grazed, but not harvested

5. Carbon Cycle
5

6. • Improving soil quality through aggregation
Soil Regeneration
6

7. • Building soil OM and feeding the Soil Food Web
Soil Regeneration
7

8. • Improving water infiltration and moisture retention
Soil Regeneration
8
So this doesn’t happen
Photos by Rex Dufour, NCAT

9. • Keeping soil in place and preventing erosion
Soil Preservation
9

10. • Smother crops and allelopathy
Chemical-free Weed Control
10

11. • Controlling diseases and nematodes
– Phytophthora blight
– Verticillium wilt
Chemical-free Disease Suppression
11
Bio-fumigant mustard cover crop in high tunnel.
Photo by Elena Garcia, U of AMarigold can suppress root-knot, lesion,
and reniform nematodes.
Photo attributed to Steve Groff

12. • Contributing Nitrogen (legumes)
• Recycling, capturing N (non-legumes)
Building Soil Fertility
12

13. • Attracting pollinators & beneficials
Promoting Biological Diversity
13

14. Summer cover crops
Cover Crop Species for AR & OK
14
Winter cover crops
Grasses
Legumes
Non-legume
broadleaves
(Brassicas)

15. • Sorghum-Sudangrass (Sudex)
– Seeded at 35-50 lb/a
– Weed suppression
– N scavenger
– 6+ ft tall
– 8-10k lb/a DM
– Mowed when 3-4’
– Drought-resistant
– Winter kill
Summer Grasses
15

16. • Pearl millet
– Seeded at 15-20 lb/a
– 4-6 ft tall
– 60-70 DTM
– Can be difficult to kill
– Also German foxtail,
and Japanese millet
Summer Grasses
16

17. • Cowpea (Southern pea)
– ‘Iron and Clay’
– Seeded at 40-75 lb/a
– 60-90 DTM
– Drought tolerant
– 3-4k lb/a DM
– Can fix 75 lb N/a
– Mix with Sudex or
millet
17

18. • Sunn hemp
(Crotalaria juncea)
– Seeded at 30 lb/a
– Weed control
– 9’ in 60 days
– 100-140 lb N/a
– Drought-tolerant
– Woody after 60 days
18
Sunn hemp terminated by
walk-behind roller-crimper.
Photo by Carolina Farm Stewardship
Association

19. • Buckwheat
– Seeded at 48-90 lb/a
– Fast-growing
– Flowers in 30-45 days
– 2.5’ tall
– Allelopathic
– Beneficial habitat
– Can become weedy
19

20. • Cereal rye (Secale cereal)
– Seeded at 100 lb/a
– Grows to 3-6’ tall
– Extensive root system
– Weed suppressive
– Catch crop
Winter Grasses
20

21. • Oats
– Seeded at 100 lb/a
– Nurse crop
– Rapid ground cover
– Grows 2-5’ tall
– Will winter-kill
21
Photo by Bob Bugg, University of California
Photo from the Ohio State University

22. • Crimson clover
– Seeded at 15-20 lb/a
– Significant growth in
spring
– Can fix 160 lbs N/a
– Can be overseeded
into fall vegetable
plots
Winter Legumes
22

23. • Hairy vetch
– Seeded at 20-30 lb/a
– Will fix 150 lb N/acre
– Can become weedy
– Will climb tall grain
crops
23

24. • Austrian winter pea
– Seeded at 60-90 lb/a
– Sown as late as Oct.
– Will fix 130 lb N/acre
– Mixes well with rye or
wheat
24

25. • Tillage/Daikon radish
– Seeded at 8-20 lbs/a
– Fast growing
– Suppresses weeds
– Bio-drilling
– Winter-kills
25

26. • Mustard
– Seeded at 5-15 lbs/a
– Fast growing
– Catch crop
– Allelopathic
– Glucosinolates act
as bio-fumigant
– Beneficial habitat
Brassicas
26

27. Multi-Species Mixes
27
• Diversity
• Grass/legume
• C/N ratio
• Height
• Rooting depth
Examples
• Rye + crimson clover
• Rye + hairy vetch
• Oats + radish +
winter peas
• Sudex + cowpeas
• Sudex + sunn hemp +
sunflower + cowpeas

28. Managing cover crops
28

29. Planting and establishment – Seed drill
29
Small-scale grain drill.
Photo by Jordan Engineering,
jordanatveng.com
Timing of
planting is key

30. Planting and establishment –
Broadcasting
30
Hand-crank seed
broadcaster.
Photo from
smallfarmtools.com

31. Planting and establishment –
Incorporating seed
31

32. Planting and establishment –
Irrigation?
32

33. Cover crop care – Irrigation & mowing
33

34. Termination
34

35. Reproductive phase: After flowering / before hard seed
Termination – WHEN?
35
Soft dough

36. Termination - Mowing
36
Sickle bar
Flail mower
Photo by Local Roots Farm
Bush hog
Photo by Becky Sideman, from MOFGA.org
EarthtoolsBCS.com

37. Termination – Small scale solutions
37
Weed eater
Scythe/sickle

38. Termination – Roller/crimper
38

39. Incorporation
39
Incorporating cover crop with disks.
Photo by Canewater Farm
Plowing in cover crop.
Photo by Mark Schonbeck, VABF
Tilling in cover crop. Photo by Butternut Valley Farm

40. • Surface mulch
No-Till
40

41. • Small-scale application  residue management
Incorporation – or not?
41

42. • Small-scale application  surface mulch
No-Till
42

43. • Planting too late
• Cover crop becoming a weed problem
• Not being able to terminate in time
• Planting delay (3 weeks after incorporation)
• C-rich biomass resulting in N tie-up
• Cold soils from cover crop mulch
Potential pitfalls
43

44. Assessing cover crop performance
44

45. Biomass production by height
• Rule of Thumb Estimate:
– For 100% groundcover
– 6 inches = 2,000 lb/acre DWT
– Additional in. = 150 lb/acre
• Example:
– Cover crop 5’10” = 70 in.
– (2,000 lb) + (64)(150 lb)
= 2,000 + 9,600
= 11,600 lb/acre DWT
Assessing cover crop performance
45

46. Biomass production by weight
• Use quadrat
– 1x1 m or 3x3 ft
• Cut biomass
• Place in bag or sack
– Tear weight of bag
• Dry biomass
• Weigh biomass
• Calculation
– 43560 sq ft = 1 acre
– For 3x3 ft sample:
___ lb x 4840 = ___ lb/acre dry matter
Assessing cover crop performance
46

47. Assessing performance – Benchmarks
47
Cover crop Dry matter (lbs/acre)
Sorghum-Sudangrass 8,000-10,000
Grain rye 3,000-10,000
Oats 2,000-10,000
Buckwheat 2,000-4,000
Mustard 3,000-9,000
Radish 4,000-7,000
Cowpea 2,500-4,500
Crimson clover 3,500-5,500
Austrian winter pea 4,000-5,000
Hairy vetch 2,300-5,000

48. • Legumes
• Nodulation
• Inoculation
• Timing of
termination
Maximizing N fixation
48

49. Calculating biomass N
• N% of cover crop biomass
– Legumes: 3-4% N
– Cereals: 1.5-2.5% N
– 50/50 mix: 2.5-3% N
• Biomass N (lb/a) = N% x Dry wt biomass (lb/a)
• 50-60% of N will be plant available (PAN)
Cowpea example: 4,000 lb/a DM and 3.5% N
Biomass N = 0.035 x 4,000 x 0.5 = 70 lb/a PAN
Assessing N fixation
49

50. Assessing N fixation
50
Legume N content (lbs/a)
Cowpea 75-150
Sunn hemp 100
Crimson clover 70-150
Austrain winter pea 90-150
Hairy vetch 60-120*
*Studies have shown hairy vetch to contribute as much as
100 lbs/a of plant-available N

51. • Fertilizer N reduction with legumes
– Expect fertilizer replacement of 50-100 lb N/a
– Oregon State University study demonstrated savings of
$500/a using vetch cover crop instead of feather meal in
organic broccoli (Garrett, 2009)
https://www.uvm.edu/vtvegandberry/NMP/PANFromCoverCrops.pdf
• Cost of cover crop PAN estimated at $2-3/lb
• Cost of PAN from feather meal fertilizer $5/lb
Economics of cover cropping
51

52. • Fertilizer reduction
– Kansas study showed Austrian winter peas and hairy
vetch could provide enough N for muskmelons in
plasticulture system without additional fertilizer
(Singogo, 1996)
• Yield compared to fertilizer rates of 63 to 90 lbs N/a
Economics of cover cropping
52

53. • Oregon State University study (Luna, 2009)
– Oat-legume cover crop led to net increase of $50/a in
revenue for organic corn production
– Phacelia-vetch cover crop increased broccoli production
by 1.3 tons/a compared to fallow
• $2,370 increase in economic value per acre
– Oat-vetch cover crop increased broccoli yield when
fertilized at 90 lbs/acre
• $3,460 increase in economic value per acre
From SARE Project “Managing cover crop and conservation tillage systems to
enhance vegetable crop yields, economic returns and environmental quality”
Economics of cover cropping
53

54. • Reduced cost of weed control
– Biological management
– Bio-extensive system  “Weed the soil”
– Weed-suppressive killed mulch
Economics of cover cropping
54
Pumpkins planted into killed rye cover crop.
Photo by Ajay Nair, Iowa State University
Cover crops allow the Nordells to run a 6 acre
market garden with just 2 people and horses.
Photo from uvm.edu

55. Innovative applications
55

56. Cover crops for a Regenerative
Agriculture
56
• Conserving our soil resources
• Building soil with carbon fixation
• Improving biological productivity of soils
• Biological solutions to pest problems

57. greencoverseed.com/
Cover crop seed
57
www.deercreekseed.com/
www.johnnyseeds.com/farm-seed/
www.groworganic.com/
www.southernexposure.com/

58. Resources
58
• ATTRA
• www.ncat.attra.org
• SARE Cover Crops Topic Room
• http://www.sare.org/Learning-
Center/Topic-Rooms/Cover-Crops
• Managing Cover Crops Profitably
• NCSU Growing Small Farms, Cover
Crops Portal
• https://growingsmallfarms.ces.ncsu.ed
u/growingsmallfarms-covcropindex/
• UC Davis SAREP Cover Crop Database
• http://asi.ucdavis.edu/programs/sarep
/research-initiatives/are/nutrient-
mgmt/cover-crops-database1
https://www.uvm.edu/vtvegandberry/
NMP/PANFromCoverCrops.pdf

59. Questions?
Luke Freeman
lukef@ncat.org
479-442-9824
ATTRA Hotline
1-800-346-9140
Attra.ncat.org
www.slideshare.net/lfreeman89/