Soybeans

Cover Crop of Soybeans
Figure 1. Cover Crop of Soybeans
Root Systems 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

 

Soybean Root System
Figure 3. Soybean Root System

Control Options

  • Winterkills readily; controlled by tillage and chemical if necessary

Sensitivity to Herbicides

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

  • Soybean 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

Family

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

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

  • Both 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

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