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The role of soil hydraulic conductivity on the spatial and temporal variation of root water uptake in drip-irrigated corn
Year:
2002
Source of publication :
Plant and Soil
Authors :
Cohen, Yehezkel
;
.
Volume :
243
Co-Authors:
Li, Y., Department of Soil and Water Sciences, Faculty of Agricultural, Food, and Environmental Quality Sciences, Hebrew University of Jerusalem, P.O. Box 12, Rehovot 76100, Israel, Institute of Soil, Water and Environmental Sciences, ARO, Bet Dagan, Israel, Xinjiang Institute of Ecology and Geography, CAS, Urumgi, Xinjing 83001, China
Wallach, R., Department of Soil and Water Sciences, Faculty of Agricultural, Food, and Environmental Quality Sciences, Hebrew University of Jerusalem, P.O. Box 12, Rehovot 76100, Israel
Cohen, Y., Institute of Soil, Water and Environmental Sciences, ARO, Bet Dagan, Israel
Facilitators :
From page:
131
To page:
142
(
Total pages:
12
)
Abstract:
A multiplexed TDR system and a heat-pulse system for stem sap flow measurements were used to determine the spatial and temporal pattern of root water uptake in field-grown corn. The TDR probes, 0.15 and 0.30 m in length, were buried vertically in the soil profile to a depth of 0.95 m below the soil surface and heat-pulse sensors were installed on the plant base. Nocturnal readings from TDR probes were used successfully to differentiate the two components of moisture change: root uptake and net drainage. The instantaneous rate of water extraction by the plant measured by the heat-pulse system agreed well with the integrated rate of root water uptake measured frequently (at half-hour or hourly intervals) by the TDR probes. This agreement enabled further exploration into the cause of the evolution of the spatial and temporal patterns of root water uptake during a drying cycle. The results indicated that right after irrigation in the well-watered soil profile, it is the spatial distribution of the roots that mainly determines the typical pattern of root extraction, in addition to the fact that the roots near the plant base are more effective than those farther away. The higher density and effectiveness of the roots near the plant base dry the soil rapidly so that soil hydraulic conductivity soon becomes a limiting factor for water uptake. Further analysis revealed that a decrease in root uptake occurs near the plant base under a given atmospheric demand when the relative bulk soil hydraulic conductivity decreases to 0.002Kr. This suggests that low conductivity (high resistance) in the soil near the plant base is the initial cause for downward and lateral shifting of the root uptake pattern. Note that this critical value of hydraulic conductivity is not universal since it depends on the soil type and atmospheric water demand during the period under observation. Therefore, prior to the application of moisture content or suction head as measures of water availability or to control irrigation scheduling, it is suggested that these parameters be calibrated by the soil K(θ) or K(ι) curves, respectively, for the expected atmospheric water demand for the specific crop and growing period.
Note:
Related Files :
root
sap flow
Soil hydraulic conductivity
TDR
temporal variation
Water uptake
Zea mays
Show More
Related Content
More details
DOI :
10.1023/A:1019911908635
Article number:
Affiliations:
Database:
Scopus
Publication Type:
article
;
.
Language:
English
Editors' remarks:
ID:
21175
Last updated date:
02/03/2022 17:27
Creation date:
16/04/2018 23:42
You may also be interested in
Scientific Publication
The role of soil hydraulic conductivity on the spatial and temporal variation of root water uptake in drip-irrigated corn
243
Li, Y., Department of Soil and Water Sciences, Faculty of Agricultural, Food, and Environmental Quality Sciences, Hebrew University of Jerusalem, P.O. Box 12, Rehovot 76100, Israel, Institute of Soil, Water and Environmental Sciences, ARO, Bet Dagan, Israel, Xinjiang Institute of Ecology and Geography, CAS, Urumgi, Xinjing 83001, China
Wallach, R., Department of Soil and Water Sciences, Faculty of Agricultural, Food, and Environmental Quality Sciences, Hebrew University of Jerusalem, P.O. Box 12, Rehovot 76100, Israel
Cohen, Y., Institute of Soil, Water and Environmental Sciences, ARO, Bet Dagan, Israel
The role of soil hydraulic conductivity on the spatial and temporal variation of root water uptake in drip-irrigated corn
A multiplexed TDR system and a heat-pulse system for stem sap flow measurements were used to determine the spatial and temporal pattern of root water uptake in field-grown corn. The TDR probes, 0.15 and 0.30 m in length, were buried vertically in the soil profile to a depth of 0.95 m below the soil surface and heat-pulse sensors were installed on the plant base. Nocturnal readings from TDR probes were used successfully to differentiate the two components of moisture change: root uptake and net drainage. The instantaneous rate of water extraction by the plant measured by the heat-pulse system agreed well with the integrated rate of root water uptake measured frequently (at half-hour or hourly intervals) by the TDR probes. This agreement enabled further exploration into the cause of the evolution of the spatial and temporal patterns of root water uptake during a drying cycle. The results indicated that right after irrigation in the well-watered soil profile, it is the spatial distribution of the roots that mainly determines the typical pattern of root extraction, in addition to the fact that the roots near the plant base are more effective than those farther away. The higher density and effectiveness of the roots near the plant base dry the soil rapidly so that soil hydraulic conductivity soon becomes a limiting factor for water uptake. Further analysis revealed that a decrease in root uptake occurs near the plant base under a given atmospheric demand when the relative bulk soil hydraulic conductivity decreases to 0.002Kr. This suggests that low conductivity (high resistance) in the soil near the plant base is the initial cause for downward and lateral shifting of the root uptake pattern. Note that this critical value of hydraulic conductivity is not universal since it depends on the soil type and atmospheric water demand during the period under observation. Therefore, prior to the application of moisture content or suction head as measures of water availability or to control irrigation scheduling, it is suggested that these parameters be calibrated by the soil K(θ) or K(ι) curves, respectively, for the expected atmospheric water demand for the specific crop and growing period.
Scientific Publication
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