During the drive home from Santa Fe I studied my notes of the conference and developed a list of things we will try and reflected on some issues we cannot resolve but should follow. My favorite quip was “we need to think outside the crop” shared by Anita Hall, Executive Director of AOSCA (Association of Official Seed Certifying Agencies). Seed testing developed with the increasing sophistication of agriculture and crop hybridization. This harkens back to the inherent tension underlying the whole conference between big growers and restoration purists. As I experimented with an aspirator Carey assembled based on a session we both attended, I remembered the suggestion by one ecologist that seeds of all sizes must be included in a harvest lot to preserve maximum genetic diversity. But to do that you also end up with broken pieces of larger seeds, some insect injured seed, and even bits of stem when processing with standard equipment. A seed test on such a lot would find low purity. So should we be testing seed diversity rather than purity? No. It isn’t right to charge someone for particles that won’t germinate or grow like the damaged seed and chaff. There’s also the challenge of planting non-uniform seed. Standard seed drills tend to clog when native seed is run through them. For storage in a seed bank, selecting lots with a greater range of seed size makes sense. But then the geneticist posted a graphic (Andrea Kramer):
Each stage of the seed acquisition process can diminish genetic diversity. So for the purpose of offering greatest diversity we should be seeding a broader range of seed and we should plant up and down the hill to maximize the hydrological range of growing conditions. By only planting along a certain elevation we are selecting for seed that prefers to grow with that amount of moisture and solar exposure. We also need to harvest our foundation seed from a larger population. I’m reasonably certain we have accomplished this by harvesting from some singular large populations and supplementing with seed harvested from other locations with smaller numbers, e.g. along a county road adjacent to a remnant grassland.
My list of things to try:
- Conventional cover crops for weed suppression
- Native cover crops for weed suppression
- Sod scalping smooth brome to suppress it and reseed with native pioneer species
- Plots up and down slope
- Pre-emergent herbicide?
- Broaden foundation seed collection sources
All in all it was a very good conference, thought provoking. I’ll add to this post as the memories recur.