Location: Soil and Water Management ResearchTitle: Field evaluation of conventional and downhole TDR soil water sensors for irrigation scheduling in a clay loam soil.
|Evett, Steven - Steve|
|MAREK, THOMAS - Texas A&M Agrilife|
|HEFLIN, KEVIN - Texas A&M Agrilife|
|BELL, JOURDAN - Texas A&M Agrilife|
|Brauer, David - Dave|
Submitted to: ASABE Annual International Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 3/29/2021
Publication Date: N/A
Technical Abstract: An evaluation of commercially available time domain reflectometry (TDR) soil water sensors to quantify soil profile water for irrigation scheduling was performed in a research field near Bushland, TX, in 2020. An array of Acclima TDR-315L and -315H sensors and Campbell Scientific SoilVUE10 downhole sensors were installed adjacent to neutron moisture meter (NMM) access tubes in three irrigation treatment plots that received 100, 75, and 50 percent of corn seasonal crop water requirements. Acclima TDR-315 sensors were installed at depths equal to those of the 1.0-m long SoilVUE10 sensors (5, 10, 20, 30, 40, 50, 60, 75, and 100 cm). Biweekly NMM readings were taken at the same depths throughout the growing season, typically preceding and following irrigation events. Comparisons of volumetric water content (VWC) from both sensors at each depth were performed along with integrated soil profile water calculations. Results indicated that both sensors agreed relatively well with NMM data under fully irrigated conditions. However, in general, the values from the Acclima 315 sensors were larger while those from the SoilVUE sensors were smaller as compared with NMM measurements. Discrepancies in VWC were observed at shallow depths for both sensors, presumably from poor soil to electrode contact during drying periods. The SoilVUE appeared to suffer from soil contact issues in the limited irrigated treatments, worsening as soil profiles dried over time. Associated soil profile water values differed from those obtained from NMM readings but could be useful for irrigation in clay soils if appropriate data filtering and processing were used.