[APWG] Ecosystem Restoration Cheating Cheatgrass Re: Purple in cheatgrass

[Wayne Tyson]

APWG: 

Dremann brings up an interesting point about low P in the soils inhabited by cheatgrass. Soil P is not the same as tissue P, and those two measurements should always go together. 

Since the natives grasses are obligately mycorrhizal and cheatgrass isn't (kindly correct me if I am wrong), and since mycorrhizae are pathways for P to the indigenous grasses, and if the soils are non-mycorrhizal, perhaps the addition of indigenous mycorrhizal fungi would tip the scales in favor of the indigenous species. A turfing grass like Leymus (Elymus) triticoides should almost certainly wipe out the cheatgrass (and almost everything else). The Leymus hybrids which have developed in response to disturbance (Stebbins, G. Ledyard--forgot the reference, but it was in the 1950's, and some personal communications) are especially "good" (or "bad") at this, having hybrid vigor--they may or may not be present in some areas. Some of the commercially-produced inocula might work, but I would confirm that before I spent a fortune on a large-scale project (All large-scale projects should begin with a proof-of-concept demonstration project on a small scale. 

Of course, as the indigenous species did not evolve with non-migratory sheep and cattle in large numbers or at all, their continued presence will prevent any restoration project from being worthy of the name, and most likely very short-lived. The indigenous species are sensitive to excessive trampling, not to mention overgrazing. 

Good luck!

WT


  ----- Original Message ----- 
  From: craig at astreet.com 
  To: srmckay at students.tvcc.cc ; apwg at lists.plantconservation.org 
  Sent: Thursday, January 17, 2013 11:09 AM
  Subject: [APWG] Purple in cheatgrass


  Dear Shawn and All,

  Hello to our weed friends from down under.  Sorry to hear that you have cheatgrass in Australia.

  In replanting a square miles of cheatgrass land in 1994-5 in our Great Basin, that you can see at http://www.ecoseeds.com/greatbasin.html, we found that the cheatgrass always indicated phosphorus poor solis.  

  So poor in fact, that without fertilizer, we could got get the local native seeds to survive as seedlings, like you can see at http://www.ecoseeds.com/good.example.

  From looking at photo vegetation megatransects of Australia, that you can see at http://www.ecoseeds.com/australia.megatransect.html, your land is in the same  vulnerable condition as a lot of our arid lands are.  In that the local native grass cover has been grazed away, leaving scattered shrubs, like you can see at the photo coordinates of 24S-139E, with lots of bare areas for the cheatgrass to colonize.

  We invented a rule of thumb for cheatgrass--Cheatgrass is a default-weed, only growing where the local native grasses have become spatially extinct, or where soil nutrients have dropped below the threshold required b y the local native seedlings to properly survive.

  We found that for each species of native grass that we replanted on the site, each had a different range of soil nutrient thresholds that they required for seedling survival.  Poas and Sitanion (now Elymus) had the lowest requirement, and Great Basin wild rye (another Elymus)  had the highest, and this was all determined by doing soil tests for N-P-K and soil carbon content.

  Current images of my Palo Alto California grassland plots, that are still 99.999% weed-free as on Monday, can be seen at http://www.ecoseeds.com/arastradero.html.  A big contrast to the land just outside of the test plot, the thistle plants are 3 per sq. inch, and the exotic grasses 8 per sq. inch, which translates to 18 million and 50 million weed seedlings per acre.  I hope this encourages others to try native straw mulch elsewhere on the planet.

  Sincerely,  Craig Dremann (650) 325-7333









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