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Time Series Analysis of Field‐Measured Water Content of a Sandy Soil
Author(s) -
Wu L.,
Jury W. A.,
Chang A. C.,
Allmaras R. R.
Publication year - 1997
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/sssaj1997.03615995006100030005x
Subject(s) - water content , reflectometry , soil science , irrigation scheduling , soil water , environmental science , time domain , content (measure theory) , hydrology (agriculture) , mathematics , geology , geotechnical engineering , mathematical analysis , computer science , computer vision
Prediction of the field soil water regime is important for assessing agrochemical transport and scheduling irrigation. This research was conducted to evaluate the potential for employing the time series analysis technique to predict average water content ( W AVG ) of a soil profile and water content at depths of interest from measurements made at a single depth. Volumetric water content of a Zimmerman fine sand (mixed, frigid Argic Udipsamment) in Princeton, MN, was measured in situ by time domain reflectometry at six depths during the early 1993 growing season. The time series made up of hourly measurements of soil water content was first‐order differenced to obtain stationarity. The differenced data were used to conduct analyses in the frequency domain to evaluate the coherence and cross‐amplitude between two soil water content time series and were subsequently fitted to autoregressive moving average models to obtain coefficients for the transfer function models in the time domain. The transfer function models were then used to predict water contents at depths of interest (50‐, 75‐, and 100‐cm depths) and W AVG in the top 100‐cm profile from measured water content at the 25‐cm depth. Overall, the predictions were reasonable, with accuracy increasing as the separation distance from the 25‐cm depth decreased.