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Evaluation of TDR Use to Monitor Water Content in Stem of Lemon Trees and Soil and Their Response to Water Stress
Author(s) -
Nadler Arie,
Raveh Eran,
Yermiyahu Uri,
Green S. R.
Publication year - 2003
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2003.4370
Subject(s) - irrigation , orchard , soil water , main stem , growing season , horticulture , environmental science , water content , agronomy , biology , zoology , hydrology (agriculture) , geology , soil science , geotechnical engineering
The purpose of the study was to compare the response of TDR‐determined stem (θ stem ) and soil (θ soil ) water content to different irrigation managements. θ stem (L L −1 ) was measured with three‐rods TDR probes (70 mm) installed vertically or horizontally into predrilled holes in the trunk of 5‐yr‐old lemon [ Citrus limon (L.) Burman f.] trees in a semiarid region (Israel). Four irrigation treatments were established to deliver 100% (“full”), half of this amount on one side of the tree (“50%”), same amount as in 50% but applied to alternate sides (3‐wk intervals) of the tree (“split”), and 0% (“dry”) of the orchard's normal irrigation volume (typically 150–200 m 3 wk −1 ha −1 ). Treated sewage water (σ w = 0.9 dS m −1 ) was used to irrigate the trees for 75 d (end of June and mid September). Changes in θ soil , and θ stem were monitored at weekly intervals. Leaf water potential and temperature measurements were used to verify the achieved water stress levels. θ stem of the full treatment fluctuated by about 0.02 to 0.03 L L −1 above and below the “prestress” reference level (beginning of the season). In contrast, θ stem of the 50% treatment declined (by about 0.07 L L −1 ) steadily over the season. For the split and dry treatments, θ stem decreased by about 0.12 L L −1 relative to the reference level. θ soil and θ stem values suggest that some surplus irrigation was applied to the full and 50% treatments. It was found that water stress was reflected in TDR‐measured θ stem changes but that these changes were too small for routine irrigation control.