Cover CropBased ConservationAG Systems for Organic Vegetable Production

1

• Cover Crop-Based Conservation-AG Systems for
  Organic Vegetable Production
• Dr. Ron MorseDepartment of HorticultureVirginia
  Tech

2
(No Transcript)
3
What is ConservationAgriculture (CA)?

• CA is a bio-diverse paradigman holistic attempt
  to mimic natural agroecosystems.
• CA strives to simultaneously obtain high crop
  yields and conserve or ideally enhance soil
  quality on an annual or biannual basis.

4

• CA Emphasizes Use of
• minimal soil disturbance
• (reduced tillage)
• permanent soil cover
• (living or dead mulch)
• intensive crop rotations
• or perennial sods

5

• Question Why integrate organic and CA?
• Answer Integrating organic and CA makes an ideal
  system (system ideotype) because their combined
  philosophies and practices best mimic native
  agroecosystems and are thus highly sustainable.

6

• Current status of Organic CA Systems
• Organic CA is not widely practiced throughout the
  world.
• Why? Its hard to break out of old traditions!
• Organic growers have traditionally used
  mechanical cultivation to manage weeds.
• CA farmers have traditionally used chemical
  herbicides to manage weeds.

7

• Question Is organic CA an oxymoron?
• Answer Although difficult, organic CA crops can
  be successfully produced using high-biomass cover
  crop-based techniques.

8

• Situations in which organic CA is least likely to
  succeed
• 1. Compacted, poorly drained soils
• Possible solutionuse permanent raised
  beds.

9
(No Transcript)
10
(No Transcript)
11

• Situations least likely to succeed
• 2. Cold, wet spring soils
• Possible use winter-kill cover crops
  and shallow zone-till in early-mid
  spring.

12
(No Transcript)
13

• Situations least likely to succeed
• 3. Weedy fields especially perennials
• Possible solutionuse aggressive IWM
  practices for 12-36 months to lower
  weed seedbank.

14
(No Transcript)
15
(No Transcript)
16

• Situations least likely to succeed
• 4. Imbalanced, infertile soils
• Possible solutionuse aggressive INM
  practices to achieve nutrient- balanced
  fertile soils.

17
(No Transcript)
18

• Situations in which organic CA is
• most likely to succeed
• 1. Sloping, highly erodible soils

19
(No Transcript)
20

• Situations most likely to succeed
• 2. Late summer planted crops

21
(No Transcript)
22

• Situations most likely to succeed
• 3. Crops that form a rapid, dense leaf
  canopy

23
(No Transcript)
24

• Situations most likely to succeed
• 4. Staked or erect-growing crops in which
  alleyways can be mowed

25
(No Transcript)
26

• Uses of cover crop residues
• No-till (NT)cover crops are killed andretained
  as a dense, uniform mulch over theentire field.
• NT is difficult because
• Cover crops must be mechanically killed
  before planting.
• NT systems require specialized equipment for
  plant establishment and weed management.

27
(No Transcript)
28
(No Transcript)
29
(No Transcript)
30
(No Transcript)
31
(No Transcript)
32
(No Transcript)
33
(No Transcript)
34
(No Transcript)
35
(No Transcript)
36
(No Transcript)
37

• Uses of cover crop residues
• B. No-till, living mulch (NT-LM)cover crops
  are killed only in the areas (zones) where cash
  crops are grown (grow zones) cover crops are
  keep alive (living mulch) in the alleyways
  during the growing season.
• NT-LM is difficult because
• Cover crops must be mechanically killed in
  grow zone areas.
• Specialized NT equipment is required to
  establish cash crops.
• Living mulch in alleyways must not encroach
  or shade cash crops.

38
(No Transcript)
39
(No Transcript)
40

• Uses of cover crop residues
• Green manure, zone-till (GM-ZT)cover
  crops are shallow incorporated in grow
  zones cover crops are either killed or
  keep alive in alleyways.
• GM-ZT is relatively easy because
• No specialized equipment is required for
  zone tillage and plant establishment.
• Weeds in grow zones can be managed using
  conventional methods.

41
(No Transcript)
42
(No Transcript)
43
(No Transcript)
44
(No Transcript)
45
(No Transcript)
46
(No Transcript)
47

• Uses of cover crops
• D. Green manure, conventional tillage (GM-
  CT)cover crop residues are shallow
  incorporated over the entire field.
• GM-CT is easy
• Conventional equipment is readily
  available.
• Weed management can be achieved using
  mechanical cultivators.

48

• Conclusions
• Although there are many associated challenges,
  organic-CA systems can produce the best of both
  worldshigh crop yields, improved soil quality,
  and many emergent or synergistic properties such
  as pest suppressiveness and crop quality.
• Success with organic CA can be achieved when
  selecting well-suited environments and following
  recommended practices examples include
• Fertile soils with low weed populations (many
  crops)
• Fall crops (broccoli) staked or erect growing
  crops (tomato)
• Crops forming rapid, dense leaf canopies (squash-
  and cabbage-family species)
• GM-ZT systems, using simple conventional
  equipment (many crops)