Location: Agricultural Systems Research Unit
Title: Performance Evaluation of Automated Passive Capillary Sampler for Estimating Water Drainage in the Vadose Zone Authors
Submitted to: American Society of Agricultural and Biological Engineers
Publication Type: Abstract Only
Publication Acceptance Date: November 10, 2008
Publication Date: June 1, 2009
Citation: Jabro, J.D., R.G. Evans, W.M. Iversen and, B.W. Stevens. 2009. Performance Evaluation of Automated Passive Capillary Sampler for Estimating Water Drainage in the Vadose Zone. Annual International Meeting of the American Society of Agricultural and Biological Engineers (ASABE) Reno, NV, June 20-24, 2009. Cd-Rom. Technical Abstract: Passive capillary samplers (PCAPs) are widely used to monitor, measure and sample drainage water under saturated and unsaturated soil conditions in the vadose zone. The objective of this study was to evaluate the performance and accuracy of automated passive capillary sampler for estimating drainage water below the rootzone of a sugarbeet-potato-barley rotation under two irrigation frequencies (30 mm and 15 mm replacements). Twelve automated PCAPs with sampling surface dimensions of 31 cm width * 91 cm long and 87 cm in height were placed 90 cm below the soil surface in a Lihen sandy loam (sandy, mixed, frigid Entic Haplustoll) at the USDA-ARS Nesson Valley irrigated research farm located approximately 23 miles east of Williston, ND. Drainage water was manually extracted from the PCAPs weekly from May to mid-August, biweekly until late September and monthly thereafter until mid-November. The cumulative manually extracted drainage water was compared with the cumulative volume of drainage water recorded by the datalogger from the tipping bucket using several statistical methods. Statistical analyses indicated good agreement between the manually extracted and logged drainage water volumes. The statistical parameters, Md and RMSE indicated that small differences existed between extracted drainage water by pump and drainage water recorded by the datalogger from the tipping buckets. Our results confirmed that our automated PCAPs are accurate, effective and provided convenient means for estimating water drainage in the vadose zone without the need for costly and manually time-consuming supportive systems.