A Technique of Zone Delineation Using Apparent Electrical Conductivity : Paddy field zone delineation using ECa and its relationship to the chemical and physical properties of soil

Spatial variability and temporal variability of soil chemical and physical properties within a field is unavoidable. Meanwhile, laboratory soil test is usually time consuming and laborious. To satisfy the concept of precision farming, rapid and intensive soil sampling is necessary for describing the uncertainty within a field. Apparent or bulk soil electrical conductivity (ECa) technique for describing soil spatial variability is widely used. ECa includes soil salinity and soil texture. Soil texture has high correlation with soil cation exchange capacity (CEC) hence, soil nutrient contents.The study showed that most of the soil properties and ECa changed from one season to other seasons, except total N. Many soil properties had the same mean values for seasons 1 and 3 such as K, moisture content, silt and coarse sand. Spatial variability of shallow and deep ECa had the same pattern for different seasons even though the mean values were different. Deep ECa showed the pattern of former canal routes clearly as continuous lines about 45 m wide at the northern and central parts of the study area.