Soil electrical resistivity monitoring as a practical tool for evaluating irrigation systems efficiency at the orchard scale: a case study in a vineyard in Central Chile

Abstract

In many orchards, irrigation scheduling is designed based on data from meteorological networks and considering homogeneous soil properties. Such assumptions may result in inefficient irrigation, which is difficult to constrain without expensive or invasive techniques. Here we have evaluated the ability of the electrical resistivity tomography (ERT) for detecting meterscale irrigation uniformity and deep percolation during irrigation. The spatiotemporal variability of soil volumetric water content (VWC) in a vineyard located near Santiago (Chile) was inferred using ERT monitoring of two irrigation cycles. The electrical resistivity structure up to 4 m depth was estimated using two-dimensional inversion of ERT data. ERT results were verified by comparing resistivity models with VWC measured with soil moisture sensors, soil properties mapped in a 2 m-depth soil pit, and the spatiotemporal evolution of VWC obtained by solving numerically Richards equation. Largest temporal variations of resistivity were observed within the root depth (1 m) and are consistent with expected relative changes in VWC during irrigation. ERT images exhibit lateral changes in resistivity at these depths, likely indicating non-uniform infiltration of water controlled by observed soil texture variations. Resistivity changes were also observed below the root zone, suggesting that a fraction of the irrigation water percolates downward. These findings can be explained by an excess of irrigation water applied during the monitoring, which was planned considering regional evapotranspiration (ET) data that overestimated the actual ET measured at the vineyard. Altogether, our results suggest that ERT monitoring during irrigation is a cost-effective tool to constrain the performance of irrigation systems.

The Effects of Brackish Irrigation on Soil Ion Accumulation and Growth of Atriplex Species

“…Soil sampling below 2 m was recommended in peach orchards [44] to ensure that plant roots were not affecting the accumulation of salts. In additional studies [45], water and nutrient movement has been shown to be variable up to 1 m below drip irrigation sources in vineyards. Future studies with Atriplex should aim to collect soil samples at 2 m or deeper to track salt accumulation with depth and to determine if the root uptake or leaching of ions is occurring below the rootzone.…”

Soil resistivity measurements to evaluate subsoil salinity in rice production systems in the Vietnam Mekong Delta

“…In agricultural research, electrical resistivity tomography (ERT) is increasingly being used for monitoring soil moisture content (Rao et al., 2020), evaluating the effectiveness of irrigation systems on field scale through the spatio‐temporal variation of soil moisture content (Araya et al., 2021), and, as recently reviewed by Cimpoiaşu et al. (2020), the relationship between resistivity and water uptake by plants under different irrigation conditions.…”

Evaluating topsoil salinity via geophysical methods in rice production systems in the Vietnam Mekong Delta

“…In contrast, ERT has not been frequently used at agricultural scales; however, more recently, ERT has increasingly been applied to monitor the dynamics of soil salinity (Walter et al., 2018), soil moisture content (Rao et al., 2020), or water uptake by plants to improve water management (Araya Vargas et al., 2021), and as recently reviewed by Cimpoiaşu et al. (2020), the structure of the root zone.…”