TY - JOUR
T1 - Water quality changes seasonal variations in root respiration, xylem CO2, and sap pH in citrus orchards
AU - Paudel, Indira
AU - Bar-Tal, Asher
AU - Rotbart, Nativ
AU - Ephrath, Jhonathan
AU - Cohen, Shabtai
N1 - Funding Information:
Thanks to Prof. Robert O. Teskey, and Dr. Roberto Salomon Moreno for helpful discussions at initial stages of the research and during data analysis. Thanks to Victor Lukyanov and Amit K Jaiswal for Technical assistance. The project was funded by grant no. 301-0746-11 from the Chief Scientist fund of the Israeli Ministry of Agriculture . This is contribution No. 603/17 from the Agricultural Research Organization, Institute of Soil, Water and Environmental Sciences, Bet Dagan, Israel.
Publisher Copyright:
© 2017 Elsevier B.V.
PY - 2018/1/15
Y1 - 2018/1/15
N2 - Effects of treated wastewater (TWW) and fresh water (FW) on autotrophic belowground respiration and respiratory coefficients (Q10) in summer and winter were determined in a commercial citrus orchard. Efflux of CO2 from soil and the often-ignored CO2 transported in xylem sap were quantified; the latter derived from sap flux, CO2 concentration ([CO2]), pH, and temperature. Xylem [CO2] scaled with xylem sap flux, pH and temperature. TWW and summer increased xylem sap pH (by 12% and 19%), soil CO2 efflux (32% and 65%), and root respired CO2 (10–15% and 55%) in comparison to FW and winter, respectively. About twice as much CO2 from the below ground autotrophic portion of respiration moved in xylem sap as compared to that diffused from the roots into the soil, with seasonal variations of about ±10%. Maximum temperature-dependent respiratory coefficients (Q10) were 4.7 for autotrophic root respiration and 3.8 for bulk soil CO2 efflux, and values varied with water quality and season. Total below ground respiration exceeds that previously reported and is a large part of the tree's carbon balance. Increased respiratory losses caused by poor quality water may explain reduced orchard root growth and overall productivity.
AB - Effects of treated wastewater (TWW) and fresh water (FW) on autotrophic belowground respiration and respiratory coefficients (Q10) in summer and winter were determined in a commercial citrus orchard. Efflux of CO2 from soil and the often-ignored CO2 transported in xylem sap were quantified; the latter derived from sap flux, CO2 concentration ([CO2]), pH, and temperature. Xylem [CO2] scaled with xylem sap flux, pH and temperature. TWW and summer increased xylem sap pH (by 12% and 19%), soil CO2 efflux (32% and 65%), and root respired CO2 (10–15% and 55%) in comparison to FW and winter, respectively. About twice as much CO2 from the below ground autotrophic portion of respiration moved in xylem sap as compared to that diffused from the roots into the soil, with seasonal variations of about ±10%. Maximum temperature-dependent respiratory coefficients (Q10) were 4.7 for autotrophic root respiration and 3.8 for bulk soil CO2 efflux, and values varied with water quality and season. Total below ground respiration exceeds that previously reported and is a large part of the tree's carbon balance. Increased respiratory losses caused by poor quality water may explain reduced orchard root growth and overall productivity.
KW - Autotrophic
KW - Effluent
KW - Greenhouse gas emission
KW - Heterotrophic
KW - Waste water
UR - http://www.scopus.com/inward/record.url?scp=85036469768&partnerID=8YFLogxK
U2 - 10.1016/j.agwat.2017.11.007
DO - 10.1016/j.agwat.2017.11.007
M3 - Article
AN - SCOPUS:85036469768
SN - 0378-3774
VL - 197
SP - 147
EP - 157
JO - Agricultural Water Management
JF - Agricultural Water Management
ER -