Correlation of EM38 Data and Some Soil Physical Properties under Salinity Condition

Accurate، rapid، and low-cost instruments for in situ measurement of soil physical properties can simplify generation of their maps in different scales for site specific management of soil and water resources in these areas. One of these instruments is electromagnetic induction device (EM38) that has shown many capabilities in determination of some soil physical properties، both at the surface and in depth. Main objective of this study was to investigate EM38 capabilities in determination of some soil physical properties such as weighted and volumetric water contents (12θm «> and 12 θv)»>، clay، silt، and sand percentages، temperature، apparent bulk density (12ρb«>)، and porosity (n) in saline pistachio orchards of Ardakan، Yazd province. For this purpose، 90 EM38 reading points and 25 soil sampling points were selected in the region. Disturbed and un-disturbed soil samples were collected from four discrete depths (0-30، 30-60، 60-90، and 90-120 cm) and the mentioned parameters were determined. Afterwards، relationships between EM readings and different soil properties were calculated through simple and multiple regression methods. Results of this study showed no significant correlations between EM38 readings and clay، sand، silt contents and temperature، while significant correlations were found between horizontal EM38 readings (EMh) and 12 ρb»> with R2 of 0. 68 and 0. 65 for 0-30cm and 0-60cm soil depths، respectively. Additionally، relationships between EM38 and 12θv «>of 0-30cm، 0-60cm، and 0-90cm soil depths were significant with R2adj of 0. 69، 0. 74 and 0. 78، respectively. Based on these relationships، maps of 12ρb،» > 12θv«> and porosity (n) of different soil depths were prepared and interpreted. Results of this study، however، show suitability of EM38 instrument for low-cost and rapid mapping of some soil physical properties such as moisture، bulk density، and porosity.