Root water uptake and profile soil water as affected
by vertical root distribution |
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Authors: | Gui-Rui Yu Jie Zhuang Keiichi Nakayama Yan Jin |
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Institution: | (1) Institute of Geographical Science and Natural Resources Research, Chinese Academy of Sciences, Datun Road 3, Chaoyang district, 9717, Beijing, 100101, P. R. China;(2) Department of Earth and Planetary Sciences, Center for Environmental Biotechnology, The University of Tennessee, Knoxville, TN 37996-1410, USA;(3) Faculty of Horticulture, Chiba University, Matsudo 648, Matsudo city Chiba, 271-8510, Japan;(4) Department of Plant and Soil sciences, University of Delaware, Newark, DE 19717, USA |
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Abstract: | Water uptake by plant roots is a main process controlling water balance in field profiles and vital for agro-ecosystem management.
Based on the sap flow measurements for maize plants (Zea mays L.) in a field under natural wet- and dry-soil conditions, we studied the effect of vertical root distribution on root water
uptake and the resulted changes of profile soil water. The observations indicate that depth of the most densely rooted soil
layer was more important than the maximum rooting depth for increasing the ability of plants to cope with the shortage of
water. Occurrence of the most densely rooted layer at or below 30-cm soil depth was very conducive to maintaining plant water
supply under the dry-soil conditions. In the soil layers colonized most densely by roots, daytime effective soil water saturation
(S
e) always dropped dramatically due to the high-efficient local water depletion. Restriction of the rooting depth markedly increased
the difference of S
e between the individual soil layers particularly under the dry-soil conditions due likely to the physical non-equilibrium
of water flow between the layers. This study highlights the importance of root distribution and pattern in regulating soil
water use and thereby improving endurance of plants to seasonal droughts for sustainable agricultural productivity. |
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Keywords: | Actual transpiration Maize Root length density Root system architecture Sap flow Soil water potential |
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