干旱区生态环境知识资源中心

Salt concentration in soil and in the available waters in irrigated areas in the semi-arid regions is not always suitable, and it may interfere with the agricultural yield. In this work, soil salinity has been estimated from readings of an electrical magnetic device EM38 in an alluvial valley, considering the apparent soil salinity (EM). The equipment has been placed not only at the soil surface, but also at different heights above the soil level, as a way to encompass distinct vertical scales on the actual soil electrical conductivity estimation (ECr). Multiple regression models have been developed for the local conditions. The results have been analysed both by descriptive statistics and by the geostatistical methodology. The ECr estimates fitted to a logNormal distribution and presented a spatial dependence at a plot scale in the 0-30, 30-60 and 60-90 cm layers. It has been verified that the EM38 is a suitable tool for soil salinity mapping, when local calibrations are considered, at plot scale, and in the valley scale, even in areas with relevant vertical heterogeneities. Determination coefficients higher than 90% has been verified for the multiple linear regression models.