제주지역 농업용수의 이온성분 특성평가

Abstract

A well is developed and used for an agricultral water in most areas of Jeju Island. In this study, the characteristics of ionic constituents and nutrients, and the potential effect on the growth and development of upland field crops with the relationship between EC(electric conductivity) and SAR(sodium adsorption ratio), were evaluated, with the comparison of FAO's water quality guidelines for irrigation, for groundwater of public 28 wells which were developed for an agricultural water and irrigated for the upland field crops. The results obtained were as follows:

1. For the cationic(Ca2+, Mg2+ and Na+) and anionic(HCO3-, Cl-, SO42-) constituents, their concentrations were in the range of the guidelines, indicating that their water quality is available for an agricultural water. Considering the concentraions of ionic constituents with area, the concentration of Cl- was higher at the eastern area and the concentrations of the other ions were at the western areas.

2. For the nutrients(K+, NO3--N), the concentrations of the former were in the range of the guidelines at the groundwaters of 26 wells except those of for 2 wells(SS-2, SS-6), and the average concentrations of the latter with season and well were also in the range of the guidelines, although the concentrations of the 4 samples among 112 samples analyzed, exceeded the guidelines.

3. With the relationship between EC and SAR, the groundwaters of 22 wells got the values(EC < 0.2 dS/m) that cause severe problems for their infiltration rate into the soil, and the groundwaters of 6 wells got the values(0.2 dS/m < EC < 0.7 dS/m) that cause slight to moderate Problem for those.

In addition, it is reported that the physicochemical properties of soils(e.g.> soil type, the morphology of soil surface, moisture content, CEC(Cationic exchange capacity), etc) got a great effect on the infiltration rate of water into the soil.