Open AccessEffects of Three Levels of Midday Stem Water Potential on Chandler Walnut Growth and Yield in California
Author(s) -
Richard Buchner,
Allan Fulton,
Bruce Lampinen,
Kenneth A. Shackel,
Terry Prichard,
Larry Schwankl,
Sam Metcalf,
Cayle Little
Publication year - 2004
Publication title -
hortscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.518
H-Index - 90
eISSN - 2327-9834
pISSN - 0018-5345
DOI - 10.21273/hortsci.39.4.814c
Subject(s) - juglans , horticulture , irrigation , rootstock , moisture stress , environmental science , water stress , growing season , biology , botany , agronomy , moisture , chemistry , organic chemistry
Ninth leaf California Chandler Walnuts ( Juglans regia) on Northern California Black ( Juglans hindsii ) or Paradox (English/black hybrid) rootstock were irrigated to achieve three levels of Midday Stem Water Potential (MSWP). Target potentials were: 1) low water stress (average MSWP of -3.2 bars); 2) mild water stress (average MSWP of -6.2 bars); and 3) moderate water stress (average MSWP of -7.3 bars). Stem Water Potential was measured midday (12-4 pm) by placing leaves inside water impervious, light blocking foil bags. Leaves remained bagged for at least ten minutes to achieve equilibrium. Bagged leaves were removed, placed inside a pressure chamber and stem water potential was measured at endpoint. Data are presented for the 2002 and 2003 seasons. Withholding irrigation water had a significant impact on `Chandler' growth, productivity, and profitability particularly on young, vigorously growing trees. Chandler/Black appears to be more tolerant to water stress compared to Chandler/Paradox For Chandler on Paradox, water stress significantly reduced growth, yield, price per pound, percent edible kernel, and resulted in darker kernels. In addition, water stress significantly increased the total percent offgrade. Withholding irrigation does not appear to be a good strategy in young, vigorously growing `Chandler' orchards. Mature trees and trees grafted onto Northern California black rootstock may be more tolerant of moisture stress.