Cover crops: Benefits of Different Species

Cover crops have a range of benefits for soil health and nutrient management and since it's coming up to that time of year for ordering seeds, here's a rundown of the benefits of various species. 

 

 

 

 

Why implement cover cropping?

  • Increases organic matter
  • Legumes increase soil nitrogen
  • Enhancing nitrogen recycling
  • Reducing soil erosion
  • Improving the physical properties of soil
  • Disrupting insect and disease life cycles
  • Suppressing pathogenic nematodes and weed growth.

Cover crop benefits of different species

Soybean Leichardt

  • Large nitrogen contribution
  • Disease suppression
  • Taproot to reduce compaction
  • Soybean more tolerant to waterlogging than other legumes
  • Harder to establish

Soybean – Stuart

  • Large nitrogen contribution
  • Disease suppression
  • Taproot to reduce compaction
  • Soybean more tolerant to waterlogging
  • Less robust than Leichardt

Cowpea – Meringa

  • High biomass
  • Good weed competition
  • Nematode suppression (root lesion and root knot)
  • More tolerant to drier soils
  • Taproot to reduce compaction
  • Easy/fast to establish
  • Nitrogen fixing

Cowpea – Ebony

  • High biomass
  • Good weed competition
  • Nematode suppression (root lesion)
  • Nitrogen fixing
  • More tolerant of wet conditions than Meringa, still tolerant of drier soils
  • Taproot to reduce compaction
  • Easy/fast to establish

Lab Lab – Highworth

  • Good ground cover/large biomass
  • Grows well - can continue growing into autumn taking up moisture (can be difficult to kill)
  • Nitrogen fixing
  • Taproot to reduce compaction
  • Poor waterlogging tolerances
  • Slower establishment

Sunflower

  • Encourages Mycorrhizal fungi (excellent phosphorus fixers)
  • Strong taproot to break compacted soils

Tillage Radish

  • Don’t plant till autumn/April (can’t handle extremes of summer)
  • Bio-fumigant (pest and weed suppression)
  • Strong/deep taproot to break highly compacted soils
  • Good for retaining soil nitrogen following a legume crop
  • Suited to medium dry soils

Sorghum

  • Heat and moisture stress tolerant
  • High organic matter production
  • Builds organic carbon due to extensive root system
  • Good weed control due to vigorous growth.
  • Allelopathic potential in some species (weed suppression)
  • Quick to establish

Inoculants

Good inoculum coverage is essential to get the most benefits from legume cover crops. If you don’t use the right one some legumes won’t grow so well and they won’t grow nitrogen nodules, which supply nitrogen to the legume and your subsequent cane crop, allowing you to use less chemical fertiliser.

Choosing plants

While growers have traditionally planted one single species in their fallow, research is showing that there are many benefits to planting multi-species. Some growers have been experimenting with two species and others have gone even further and planted up to 10 different species.

Some multi-species cover crop benefits include:

  • Increased soil biodiversity
  • Weed suppression
  • Increased organic matter
  • Nitrogen capture
  • Permanent soil cover

For more information about cover cropping watch our video.

Comments are closed.