Quantity and Type of Salt in Water for Agriculture in Cha-am District, Phetchaburi Province
The study purposes to analyze quantity and type of salt in water used for crop production in Cha-am District, Petchaburi Province in comparison to standard criteria given by the Pollution Control Department (PCD). The study area was divided into 38 sites regarding the research scope to examine calcium, magnesium, sodium, potassium, chloride, sulfate, carbonate and bicarbonate contents in each sample site. The results illustrated average pH of 7.8, average electrical conductivity of 2.28 dS/m, average calcium of 28.205 mg/L, average magnesium of 42.953 mg/L, average sodium of 466.918 mg/L, average potassium of 67.934 mg/L, average chloride of 692.0168 mg/L, average sulfate of 34.382 mg/L, average carbonate of 152.715 mg/L and average bicarbonate of 987.410 mg/L. According to analysis results, the amount of salts in agricultural water in study area are inconsistent with PCD standard criteria. This can be caused from high tide or seawater flowing into irrigation canals. The study also suggests operational approaches to solve problems regarding to water management on saltwater intrusion. This effort can be useful for agriculturists in the study area and also other areas where the similar situation occurs.