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Citrus Water Uptake Dynamics on a Sandy Florida Entisol
Author(s) -
Morgan K. T.,
Obreza T. A.,
Scholberg J. M. S.,
Parsons L. R.,
Wheaton T. A.
Publication year - 2006
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/sssaj2005.0016
Subject(s) - evapotranspiration , soil water , field capacity , environmental science , canopy , entisol , irrigation , citrus × sinensis , water content , soil horizon , agronomy , hydrology (agriculture) , orange (colour) , horticulture , soil science , botany , biology , ecology , geotechnical engineering , engineering
Florida citrus trees must be irrigated to reach maximum production due to low soil water‐holding capacity. In a highly urbanizing state with limited water resources, improved understanding of soil water uptake dynamics is needed to optimize irrigation volume and timing. The objectives of this study were: (i) estimate mature citrus daily evapotranspiration (ET c ) from changes in soil water content (), (ii) calculate citrus crop coefficients ( K c ) from ET c and reference evapotranspiration (ET o ), (iii) determine the relationship of soil water stress coefficient ( K s ) to , and (iv) evaluate how ET c was related to root length density. In a 25‐mo field study using mature Hamlin orange [ Citrus sinensis (L.) Osbeck] trees, ET c averaged 1137 mm yr 1 , and estimated K c ranged between 0.7 and 1.1. Day of year explained more than 88% of the variation in K c when was near field capacity. The value of K s decreased steadily from 1.0 at field capacity ( = 0.072 cm 3 cm 3 ) to approximately 0.5 at 50% available soil water depletion ( = 0.045 cm 3 cm 3 ). Roots were concentrated in the top 15 cm of soil under the tree canopy (0.71 to 1.16 cm roots cm 3 soil), where maximum soil water uptake was about 1.3 mm 3 mm root 1 d 1 at field capacity, decreasing quadratically as decreased. Estimating daily plant water uptake and resulting soil water depletion based on root length density distribution would provide a reasonable basis for a citrus soil water balance model.