Arid Land Research Fund

Project #2

Assessing seed coatings for successful Indian ricegrass restoration.

Research Objective

• Determine seed coating efficacy for germination & establishment
  • Four seed coatings
  • Irrigated (simulated rainfall) and non-irrigated treatments
  • Determine role of soil temperature at two depths, (5 cm and 10 cm) on success of both irrigated and non-irrigated plots

Relevance

• Approximately 40% of the world’s rangelands are desertified. To combat desertification and improve understanding of how to restore very dry lands, use of seed coatings is being explored
• Indian ricegrass, an important perennial grass in the US Southwest, has been significantly reduced since settlement by over-grazing. It is proved difficult to reestablish – seed-coatings hold promise to be the solution

Seed Coatings

Coatings help seedlings break through crusts, delay or hasten germination, improve germination and establishment.

West side of Highway 95 (preferred)

• Loamy 5-8 ecological site
• Representative of majority of acres in the area
• Has likely experienced topsoil loss

East side of Highway 95 (not preferred)

• Sandy 5-8 ecological site
• Represents only a small number of acres
• Much more influenced by current off-road recreation use

• Best case scenario
  • Use of seed treatments greatly increases seedling germination and establishment on the non-irrigated sites leading to breakthroughs in arid last restoration and reclamation in arid environments (5-8 inches of precipitation annually).
• Possible scenario
  • Findings document that irrigation is only necessary for a short period of time to boost seedling germination and establishment with treated seeds.
• Possible scenario
  • Substantial differences are seen between seed treatments and one treatment outperforms the rest.
• Poor outcome scenario
  • Irrigation is shown to be critical in all stages of life for germination, establishment and survival of Indian ricegrass.
• Worst case scenario
  • Nothing works.