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Seed-based webinar follow-up #15 What type of seeding rates (PLS) are...
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5/4/2017 at 9:02:44 AM GMT
Posts: 38
Seed-based webinar follow-up #15 What type of seeding rates (PLS) are...

Seed-based webinar follow-up #15

What type of seeding rates (PLS) are used on the presumably bare mining soil sites?

Directed to: Todd

5/4/2017 at 9:41:13 AM GMT
Posts: 38
Todd's reply:

At least in the northern Western Australian mining industry, these pure live seed (PLS) figures are hard to come by. Unfortunately, we do not have a certification system that has been adopted by all members of the industry so many seeding rates are just ad-hoc (e.g. typically 6-8kg / ha for grasses). Some recent unpublished evaluations we have the main grass genus (Triodia spp.) is seeded at ca. 200 PLS / m2. This is far below the rate of ca. 400 PLS that I have heard of in some Great Basin restoration scenarios in the western US. In my opinion this is too low to re-instate sufficient seed numbers to the soil seed bank in completely baron (mined) land. Taking dormancy and germination impediments into consideration, there is a very high likelihood that zero germination, emergence and establishment occurs even after large rainfall events (e.g. see Lewandrowski et al (2017) Increasing the germination envelope under water stress improves seedling emergence in two dominant grass species across different pulse rainfall events. Journal of Applied Ecology, in press, DOI: 10.1111/1365-2664.12816.). This is one reason why many grass seeding attempts fail and the are not represented sufficiently in rehabilitation sites (e.g. Shackelford et al (in press) Restoration of open-cut mining in semi-arid systems: a synthesis of long-term monitoring data and implications for management. Land Degradation and Development, DOI 10.1002/ldr.2746).