[APWG] What caused surprise results in Poppy Project?--Got it!

[Robert Layton Beyfuss]

So, did you test the soils for nutrient levels? Have you learned the optimal nutrient levels for the natives that you are trying to reestablish and compared them to the soils you are now working with?

________________________________
From: APWG [apwg-bounces at lists.plantconservation.org] on behalf of craig at astreet.com [craig at astreet.com]
Sent: Wednesday, September 18, 2013 12:30 PM
To: Addsum-Tony Frates
Cc: apwg at lists.plantconservation.org
Subject: Re: [APWG] What caused surprise results in Poppy Project?--Got it!


Dear Tony and All,

You got it.!

All land plants have at least two soil nutrient thresholds. (1.) The threshold for seedling survival (2.) The threshold that larger plants can survive in.

So if you are the  manager of 200+ million acres like BLM and you have allowed exotic animal grazing for a period of time, then you may still have mature native grasses on your lands, but if you do an age-pyramid survey by measuring the basal diameters of 100 plants, you might not see any young plants or seedlings in the population.

That was the case in the 600 acre Great Basin project, where you see the seedlings die in the flat at http://www.ecoseeds.com/good.example.html.

Grazing had mined the soil nutrients and surface organic matter below the threshold needed for seedling survival.  So we had a population of old native grass plants on the 600 acres, and they were producing viable seeds each year, but no seedlings were surviving in the soil next to the mature plants.

We found that each native grass species in the Great Basin had a different seedling survival threshold, in that some species'  seedlings could survive at very low thresholds where other species required very high thresholds to keep growing.

That goes for weeds here in the West also, like cheatgrass, medusa head, Saharan mustard, Italian thistle, etc., where their seedlings can survive in soils where the nutrients have been drawn down by grazing, below the threshold required by the local native plant seedlings.

I call those soil-nutrient depleted weeds, the default weeds, and by fertilizing and bringing the soil nutrient threshold back up to where the local native seedlings need to survive, may be the easiest way to eradicate these weeds and restore the original ecosystem.

Once we start doing local soil nutrient native and weed seedling survival threshold measurements across the county, I think we will be very surprised on how many of our weed problems are caused by the lack of nutrients, and how far we need to restore the native threshold that existed before our grazing animals walked away with them.

I put details of this problem in comments to BLM in 2007, that you can read at http://www.ecoseeds.com/blmprotest.html.

Sincerely,  Craig Dremann (650) 325-7333







>
> Craig - something to do with soil chemistry?
>
> Tony
>
>
> P.S. And thanks for keeping this important conversation going.
> Clearly your methods have led to some very important successes and
> certainly shouldn't be simply ignored (and especially when the
> alternatives are what exactly?); and you were obviously most certainly
> aware of some of the negatives surrounding using pots in this fashion;
> quite clearly they can also be useful as well within those known
> limitations.
>
>
>
>
>
> Quoting craig at astreet.com:
>
>>
>>
>>
>> Dear Robert and All,
>> Thanks for your latest guess, but the mulch
>> content was the same in both pots. However, what made the
>> difference between the two pots, is a major key to the success or
>> failure
>> of getting natives established, especially here in the arid West.
>>
>> And the difference in the two pots is a common problem which
>> helps create infestations of weeds covering tens of millions of acres
>> here
>> in California and the Great Basin. The acres here in the West
>> currently covered with cheatgrass, star thistle, or medusa head grass
>> will
>> be covered for eons, and you will not be able to get any native
>> established in their place, until you correct what killed the seedlings
>> in
>> the first pot.
>> Any more guesses?
>> Sincerely, Craig
>> Dremann (650) 325-7333
>>
>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.plantconservation.org/pipermail/apwg_lists.plantconservation.org/attachments/20130918/88706912/attachment.html>