TY - JOUR
T1 - Dynamics of infiltration rate and field-saturated soil hydraulic conductivity in a wastewater- irrigated cropland
AU - Zhang, Si Yi
AU - Hopkins, Isaac
AU - Guo, Li
AU - Lin, Henry
N1 - Funding Information:
We thank Grace Billy, Chris Valdez, Zach Klueber, David Smilnak, and Heather Gall for their assistance with the field measurements. This work was supported by the Penn State's Office of Physical Plant and US National Science Foundation Hydrologic Sciences Program Grant EAR-1416881 (PI: H. Lin), GDAS Project of Science and Technology Development (2019GDASYL-0401003 and 2019GDASYL-0102002), and Guangdong Provincial Science and Technology Project(2018B030324001).
Funding Information:
Funding: This work was supported by the Penn State’s Office of Physical Plant and US National Science Foundation Hydrologic Sciences Program Grant EAR-1416881 (PI: H. Lin), GDAS Project of Science and Technology Development (2019GDASYL-0401003 and 2019GDASYL-0102002), and Guangdong Provincial Science and Technology Project(2018B030324001).
Publisher Copyright:
© 2019 by the authors.
PY - 2019/8/1
Y1 - 2019/8/1
N2 - The maintenance of a soil's infiltration rate (IR) and field-saturated hydraulic conductivity (Kfs) is crucial for the long-term sustainable functioning of wastewater-irrigated lands. However, an effective procedure for reliably measuring in situ soil Kfs remains elusive. To address this issue, this study investigated the dualhead infiltrometer (DHI), a novel instrument for automatically determining IR and Kfs, and compared it with a traditional double-ring infiltrometer (DRI) under various field conditions. In the initial phase, we optimized the procedure and settings for the DHIs in a cropland that was spray-irrigated with secondary-treated wastewater for decades in central Pennsylvania. Results showed that our optimized procedure, which used a single, long pressure cycle, yielded more robust measurements of IR than the originally recommended sequence of two short pressure cycles. The values of Kfs measured by the DHIs with optimized settings were similar to those measured by DRIs under many (but not all) field conditions, due to their differences in infiltration surface areas, operational procedures, length of infiltration time, and soil spatiotemporal variability. Viscosity-corrected Kfs on the irrigated cropland was 123.8 ± 94.0 mm·h-1, higher than that on the adjacent non-irrigated cropland (103.2 ± 94.6 mm·h-1), but the difference was not statistically significant, owing to the high degree of soil spatiotemporal variability and our limited number of measurements. Nevertheless, the higher Kfs values measured on irrigated cropland reflect observed changes in soil structure (e.g., soil pore characteristics) that resulted from decades of irrigation. Seasonal variations in Kfs values existed between winter and summer conditions, but IRs during all seasons remained much higher than the current spray-irrigation rate (4.25 mm·h-1), suggesting that the soil is still capable of handling the routine irrigation, even during winter. However, the coefficients of variation exceeded 67.0% across the field sites investigated, and the time periods covered by our measurements were limited. As this specific site is permitted to discharge treated wastewater year-round, caution must still be exercised to ensure that soil Kfs remains high enough to prevent runoff generation, especially during winter frozen conditions.
AB - The maintenance of a soil's infiltration rate (IR) and field-saturated hydraulic conductivity (Kfs) is crucial for the long-term sustainable functioning of wastewater-irrigated lands. However, an effective procedure for reliably measuring in situ soil Kfs remains elusive. To address this issue, this study investigated the dualhead infiltrometer (DHI), a novel instrument for automatically determining IR and Kfs, and compared it with a traditional double-ring infiltrometer (DRI) under various field conditions. In the initial phase, we optimized the procedure and settings for the DHIs in a cropland that was spray-irrigated with secondary-treated wastewater for decades in central Pennsylvania. Results showed that our optimized procedure, which used a single, long pressure cycle, yielded more robust measurements of IR than the originally recommended sequence of two short pressure cycles. The values of Kfs measured by the DHIs with optimized settings were similar to those measured by DRIs under many (but not all) field conditions, due to their differences in infiltration surface areas, operational procedures, length of infiltration time, and soil spatiotemporal variability. Viscosity-corrected Kfs on the irrigated cropland was 123.8 ± 94.0 mm·h-1, higher than that on the adjacent non-irrigated cropland (103.2 ± 94.6 mm·h-1), but the difference was not statistically significant, owing to the high degree of soil spatiotemporal variability and our limited number of measurements. Nevertheless, the higher Kfs values measured on irrigated cropland reflect observed changes in soil structure (e.g., soil pore characteristics) that resulted from decades of irrigation. Seasonal variations in Kfs values existed between winter and summer conditions, but IRs during all seasons remained much higher than the current spray-irrigation rate (4.25 mm·h-1), suggesting that the soil is still capable of handling the routine irrigation, even during winter. However, the coefficients of variation exceeded 67.0% across the field sites investigated, and the time periods covered by our measurements were limited. As this specific site is permitted to discharge treated wastewater year-round, caution must still be exercised to ensure that soil Kfs remains high enough to prevent runoff generation, especially during winter frozen conditions.
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U2 - 10.3390/w11081632
DO - 10.3390/w11081632
M3 - Article
AN - SCOPUS:85070546533
SN - 2073-4441
VL - 11
JO - Water (Switzerland)
JF - Water (Switzerland)
IS - 8
M1 - 1632
ER -