Selecting diverse cover crop / diverse pasture species and seeding rates

Things to think about when choosing diverse pasture / cover crop plant species

Plant species characteristics, benefits and limitations

Choose plant species for your diverse cover crop or diverse pasture that will:

• perform well in your soils, climate, slope / aspect, etc

• suit the timing of sowing, timing of grazing, stock classes, need for regrowth, etc.

• help achieve the outcome(s) you are looking for; i.e. different species can have different purposes including forage quality, forage quantity, nutrient cycling, building soil structure, attracting a diversity of beneficial insects, etc

• be cost effective and can be easily managed

• support the growth of the following crop and / or address any limiting factors (e.g. by fixing nitrogen, mobilising phosphorous, providing soil cover, tap roots addressing compaction)

• be successfully terminated when required

Livestock type

What stock classes do you want to feed? And what quality/quantity do they need and when? e.g. understanding when different plant species will be at peak quality and matching your feed curve and quality requirements to your stock classes.

Plant families and functional groups

Consider including plants from different plant families / functional groups (e.g. grasses, legumes, forbs/herbs, brassicas, chenopods) based on what you want your cover crop to achieve, and any risks you want to avoid.

• You could start with species you know to be successful in your context that will provide the bulk of forage, then add other species

• Where building soil health and function is as or more important than forage, higher diversity will help ensure something grows in each niche

• For a diverse forage crop, you can include some/all perennial species if transitioning to a permanent pasture, reducing the risk of bare ground following grazing.

Simon Osborne - Companion Cropping & Soil Health (2019)

Peter Barrett - Strategic Cover Crop Planning (2019)

“There are an increasing number of seed companies in New Zealand specialising in cover crop mixes - a quick google search will return many options, or even better, ask a farmer who they recommend from experience!”

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Considerations when deciding diverse cover crop / pasture seeding rates

Required outcomes

Seeding rates for each species should reflect the priority outcomes you want the cover crop to achieve, taking into account things like relative seed cost.

Consider starting with your minimum yield requirement and ensure what you sow will meet that need when you need that feed.

Soil conditions

If your soils are highly variable in the paddock you are sowing, increasing diversity can ensure that plant species are present that thrive in light, heavy, dry, wet, fertile, and poor areas.

Soil conditions such as wet, dry or compacted soils at or soon after drilling may favour certain species and disadvantage other species. For this reason the same seed mix can produce different results across different paddocks and seasons.

Other considerations

Leaving out species that are similar to the next cash crop that you are planting can mitigate contamination or disease risk (e.g. barley before a wheat crop).

Consider ecological succession in your plant communities; e.g. using annual species prior to or alongside your perennial species to help build soil health and improve the establishment of your perennial species.

ADDITIONAL RESOURCES

Green Cover Seeds (US Company) online seed catalogue - click on each species to see their characteristics

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