Cover Crops: Other Legumes

Table of Contents

1. Soybeans
   • Description: Family
   • Growth Habits
   • Control Options
   • Sensitivity to Herbicides
   • Weed Control
   • Benefits and Concerns
   • Getting Started
2. Clover (White, Crimson, Berseem)
   • Description: Family
   • Growth Habits
   • Control Options
   • Sensitivity to Herbicides
   • Weed Control
   • Benefits and Cautions
   • Getting Started
     
3. Related Links

Soybeans

Figure 1 - Cover Crop of Soybeans

Figure 2- Root Systems of Soybeans

Description

Family:

• Leguminosae

Growth Habits

Germination

• can be created with leftover or discarded seed
• will germinate quickly in warm, moist soils

Top Growth

• short height growth
• rapid cover if sown thickly

Overwintering

• killed by frost - do not overwinter
• need catch crop to prevent nitrogen leaching

Site suitability

• wide range of soil conditions
• less tolerant of low pH, droughty and saturated soils

Figure 3 - Soybean Root System

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Control Options

• winterkills readily; controlled by tillage and chemical if necessary

Sensitivity to Herbicides

• see OMAFRA Publication 75 - Guide to Weed Control

Weed Control

• There are many herbicides registered for use in soybeans but good weed control for a cover crop should not be expensive and may not be needed. Use narrow rows and a high enough plant population to establish a vigorous crop canopy as soon as possible.
  See OMAFRA Publication 75 - Guide to Weed Control for information on weed control measures

Benefits and Cautions

Nutrient Management

• will release N and cause leaching in winter and spring

Pest Management

• oybean cyst nematode (SCN) is a concern on many Ontario farms. Using a non-resistant variety of soybeans as a cover crop could encourage greater concentrations on farms identified with SCN.

Organic Matter

• used as forage
• residue readily breaks down

Getting Started

Establishment

• planted in fall - but some double crop soybeans after early processing peas - this can become a soybean cover crop depending upon growing conditions
• drill or broadcast seed at a rate of 80 to 100 kg/ha
• germinate quickly in warm soils if planted into moisture
• growth tends to be very short

Cost & Availability

• seed is widely available

Clover (White, Crimson, Berseem)

Description

• Trifolium spp
• Crimson Clover – Trifolium incarnatum
• Berseem Clover – Trifolium alexandrinum

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Growth Habits

Germination

• Crimson - hardseeded
  •requires moist conditions
• Berseem - same as crimson
  •will tolerate a drier seedbed

Top Growth

• Crimson - 30 to 50 cm tall
  •light - green foliage covered in soft hairs
  •striking red flower tops the plant
• Berseem - 30 to 120 cm tall
  •hollow stem, slightly-hairy leaves
  •yellowish white flower

Root System

• Crimson - simple tap-root, well nodulated
• Berseem - short tap root - top 30 cm of root zone

Overwintering

• bth are intolerant of extreme cold conditions
  •not winter hardy
  •will behave inconsistently in regions (extreme southwest or Niagara) where winters are mild

Site suitability

• Crimson:Tolerates a wide variety of soil conditions;
  •does not tolerate poor drainage and calcareous conditions
  •has a pH range of 5.0 to 7.0
  •does best on well drained, Humified, loamy soils
  •tolerates shade
• Berseem: Range = loamy and clayey soils
  •prefers soils with high silt and very fine sand contents
  •tolerates poor drainage and drought better than Crimson
  •has a pH range of 6.5 to 7.5

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Control Options

• Mowing + incorporation and chemical control will control clovers

Sensitivity to Herbicides

• Crimson – controlled by glyphosate; cyanazine or mixes of paraquat with 2,4-D, dicamba and cyanazine
• Berseem – controlled by glyphosate

Weed Control

• Clovers are frequently underseeded into a cereal crop and any weed control measures need to take crop safety of both crops into account.
• Read product labels carefully to determine if the clover species you prefer is suitable for the herbicide needed for your crop and weed situation.

Benefits and Cautions

Nutrient Management

• ability to supply N not well documented for Ontario, estimates place them similar to red clover
• due to winterkill - could lead to N loss from system in spring

Pest Management

• both are attractive to nematodes - particularly root-knot nematodes
• provide cover for beneficial insects
• Berseem - especially attractive to pollinating insects

Organic Matter

• both have a C:N of @ 10:1

Getting Started

Establishment

• requires firm, moist seedbed
• can be broadcast or drilled
• seed by six weeks before first killing frost - rate of 18 to 20 lbs/acre Crimson
• 9 to 25 lbs/acre Berseem
• should be companion planted with mixtures of : rye, vetches, annual ryegrass, and various cereals for winter protection

Cost & Availability

• seed is expensive and generally not available in Ontario

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