**4. Conclusion**

Soil test data for the Heritage Golf Course, which uses effluent water for irrigation, showed that the soil's chemical characteristics changed over time. Soil organic matter increased from 0.12 to 1.5%. Soil CEC was significantly increased by as much as double over nine years. Exchangeable Ca, Mg, K, and Na also increased by 198, 116, 148, and 452%, respectively, over nine years of effluent water irrigation. More than fourfold increase in Na could affect the soil structure and lead to a lack of aeration for roots. However, the application of gypsum can be used to minimize this effect. In addition, a significant increase over time was shown for extractable Fe, Mn, Cu, Zn, and Al.

In general, most of the chemical parameters have significantly changed over nine years of effluent water irrigation; however, not all changes are necessarily due to the use of effluent water. Some changes in soil chemistry could be the result of golf course management practices, such the use of an S-burning unit, which increased soluble S in the irrigation water. In addition, these greens are relatively young (built in 1998), they need time to become mature, and their soil becomes stable over time. However, increases in other elements such as sodium, boron, and phosphate could be due to the use of effluent water. The greater increases in SOM and estimated N release, and increases in trace elements such as Cu, Zn, and Mn could also be the result of using effluent water for irrigation.
