Astrid Volder

Astrid Volder

Position Title

  • Faculty
  • Chair - Graduate Group Horticulture and Agronomy
2057 Wickson
UC Davis, One Shields Ave, Davis CA 95616
Office Hours
During academic quarters:
W - 8 - 9.30


  • Ph.D., Utrecht University, the Netherlands; Plant Physiological Ecology, 1998
  • M.S., University of Washington, Seattle; Botany, 1997
  • B.S., Utrecht University, the Netherlands; Biology, 1994

Research interests and expertise:

Wide-ranging interests related to whole plant physiology, root biology, and rhizosphere in perennial plants, growing a range of ecosystems including urban, grazing pastures, oak-savanna, and production orchards.

Current projects:

  • Root production dynamics in almond orchards in response to irrigation and canopy management; funded by Almond Board of California.
  • Root production and lifespan in response to additional water inputs for groundwater recharge; funded by Almond Board of California.
  • The effect cover crops on soil health characteristics in pear orchards; funded by Calif. Dept. of Food and Agricultureís Healthy Soils Initiative.
  • Assessing Key Factors Influencing Farmers' Water Use and Irrigation Technology Adoption on the U.S. West Coast; funded by USDA-NIFA.
  • Direct and indirect effects of liquid organic fertilizer on root and overall plant growth; funded by industry sponsor and Jastro endowment funds.
  • Bulk soil, rhizosphere and root dynamics changes due to tillage in a vineyard ñ effects of 25 years of soil management; Jastro endowment funds.

Recently finished projects (last five years):

  • Using intercropping with halophytes to improve watermelon yield and quality under saline conditions; Texas Department of Agriculture SCRI block grant.
  • Nitrogen fertilizer impacts on root production and physiology of field-grown young pecan trees; USDA SCRI.
  • Impact of continuous water recycling on green roof media and plant performance on roofs of different ages in Houston, Texas; in-kind funding.
  • Effects of rootstock, grafting, and salinity on citrus seedling growth and salt uptake; in-kind funding.
  • Using pervious concrete to improve root zone conditions for mature Sweetgum trees ñ potential use to preserve mature urban trees; in-kind funding.
  • Impact of climate change (precipitation patterns, temperature) on oak-savanna dominant species and their interactions; funded by DOE ñ NICCR.

Current teaching:

  • Introduction to Environmental Horticulture and Urban Forestry; ENH 1 (fall quarter)
  • Urban Forestry; ENH 100, (fall quarter)
  • Arboriculture; ENH 133 (winter quarter)
  • Graduate Seminar; HRT 290, (fall quarter)

Outreach and Extension:

  • Pear research advisory council
  • Nickels research advisory council
  • Fruit and Nut center advisory board
  • Speaker at Principles of Fruit and Nut Production, Almond Production, and Walnut Production short courses.
  • Invited speaker to various grower meetings for walnut, almond, and pecan
  • Book chapters on root physiology in soilless culture textbook, as well as almond production manual

External activities that contribute to scholarship:

  • Associate editor, AoB PLANTS
  • Associate editor, California Agriculture
  • Ad-hoc reviewer for many journals and some NSF grant panels
  • Invited speaker: ASPB Northeast meeting, Western Pecan Growers, Sonora Pecan Growers (Mexico), Plant Growth Regulator Society

Prizes, Awards, Honors:

  • Montague Scholar, Texas A&M University, Center for Teaching Excellence, 2010-2011

Keywords:Plant physiology

  • Root biology
  • Rhizosphere
  • Urban ecology
  • Plant physiological ecology
  • Perennial plants
  • Ecology
  • Plant water relations
  • Plant water use