Application of a mobile electromagnetic sensing system (MESS) to assess cause and management of soil salinization in an irrigated cotton‐growing field

Abstract

Abstract. Generally, traditional soil surveys do not adequately account for the spatial variability of soil properties. Maps that are derived using these cursory soil data are likely to contain errors and thus make interpretation and soil management difficult. On the other hand quantitative methods of soil inventory at the field scale involve the design and adoption of sampling regimes and laboratory analysis that are time consuming and costly. In the latter case new technologies are required to efficiently sample and observe the soil in the field. This is particularly the case where soil salinization is prevalent, and detailed quantitative information for determining its cause is required. In this paper, a Mobile Electromagnetic Sensing System (MESS) is described and its application in an irrigated‐cotton field, located in the lower Namoi valley in New South Wales, Australia. Results from the EM38 instrument were found to be correlated with the effective cation exchange capacity (r2= 0.81). This was related to variability in soil mineralogy across the field. In addition, differences in soil chemical and textural variables, measured along a transect and adjacent to water storage, were used to identify seepage areas near a water reservoir where soil salinization was evident.

Mapping Water Table Depth Using Geophysical and Environmental Variables

“…The EM34 and EM38 have been used extensively to infer hydrological properties including topsoil depth (Sudduth et al 2001), clay content (Triantafilis et al 2001a;Triantafilis and Lesch 2005), soil mineralogy (Triantafilis et al 2002;Hedley et al 2004); salinity Corwin and Lesch 2005;Friedman 2005;Triantafilis et al 2000Triantafilis et al , 2001b; and hydrogeological units (Triantafilis et al 2003b). However, there is little peer-reviewed information specifically relating EM signal data to water table depth.…”

Mapping clay content variation using electromagnetic induction techniques

“…The most commonly used method is electromagnetic (EM) induction. EM instruments measure the apparent soil electrical conductivity (EC a ), which is a function of various soil properties including salinity, clay content, moisture content, and mineralogy (Triantafilis et al, 2002;Corwin et al, 2003). In the Netherlands, EM survey data have been used to identify the depth to (i) boulder clay and (ii) a soft layer in the western marine districts (Knotters et al, 1995).…”

Field level digital mapping of soil mineralogy using proximal and remote‐sensed data

“…The furrow lengths varied from 600 to 800 m in the west and 540 m in the east (Figure 2). Waterlogging issues at the southern end were problematic and directly related to a water reservoir located immediately to the west (Triantafilis et al, 2002) and at the southern end of the field near the head ditch. Stannard & Kelly (1977) previously described the soil of the area in which the field is located.…”