**3.6 Shallow ECa zoning characteristics**

The mean value for shallow ECa slightly increased from zone to zone and significantly isolated between zones. But, some mean values of soil properties (i.e. EC, OM, C, S, N, CEC, Ca, Na and etc.) within the shallow ECa zones did not show linear trend as per mean shallow ECa. The hypothesis for ECa zone establishment was that the soil properties within the zone were significantly different from zone to zone which indicated that soil ECa is a good zone delineator, a new classification approach for paddy soil properties.

The results indicate that the mean soil pH values within shallow ECa zone 1, 2 and 3 were not significantly different, but significantly higher than that in zone 4 and 5. However, zone 1 has significantly high OM, C, total S, total N, ESP, fine sand and sand, and significantly low Ca, total cation, BS and clay. Soil moisture, silt and coarse sand were not significantly different for all zones, at 0.05. The shallow ECa proved that zone 1 (former river) contained higher OM as compared to other parts of the study area. Therefore, to manage that area based on shallow ECa, it should be managed differently according to organic matter content. Mean shallow ECa for 5 zones has significantly negative correlation to soil pH (r = -0.95) and total S (r = -0.93) at 95% level. This indicates that soil pH and total S decreased when shallow ECa increased. Hence a good water management is to apply more irrigation water to increase the soil pH in zones 4 and 5.
