Saline Ground Water Movement Under Capillary in Soil Column for Sand and Sandy Loam in Salinity - Affected Area, Nakhon Ratchasima Province

Abstract

This paper presents experimental results in laboratory based on the investigation of saline groundwater movement influenced by capillary force. Soil layer is simulated by compacting soil sample in transparent tube of diameter 10 cm and 100 cm height and set groundwater level of 85 cm below soil surface. The experimental studies are divided into 5 different cases: 1) Column I: Sand with deionized groundwater(DG) 2) Column II: Sand with saline groundwater(SG) 3) Column III: Sandy loam with DG 4) Column IV: Sandy loam with SG and 5) Column V: Sandy loam with SG and adding artificial sunlight to increase evaporation . The experimental results show that vertical movement rate and capillary pressure head between DG and SG for sand are similar. For sandy loam sampling from salinity – affected area in Nakhon Ratchasima, the results between DG and SG are explicitly different. SG gives high capillary pressure head, high moisture movement rate and high soil moisture content compare to DG at equal level of soil depth. The cause can be that sodium ion (Na+) brought by saline water and staying in the voids between soil grain can absorb more water content. For sandy loam, soil moisture is accumulated at the soil surface in high water content, compare to the other level of soil depth. If this saline moisture is evaporated by artificial radiation, salt’s crystallization will be found on the soil surface.