Organic matter and cation exchangeable capacity of sandy soils tended to decline following the conversion of forestland to agricultural uses. Nitrogen and potassium induced by fertilization were not significantly accumulated in the topsoils, they could be rapidly transported to groundwater or runoff to surface waters. However, phosphorus could be significantly accumulated in sandy soils as extractable forms that were active and could be gradually released into groundwater and surface waters. Long-term application of fertilizers to the sandy soils influenced significantly groundwater with increased concentrations of P and N. As compared with other soils, nutrients in the sandy soils could be easily transported with water. Significant runoff of N and P was often noted in the fertilized fields during heavy rainfall. It was recommended that application of high rate of fertilizers should be avoided, and any fertilizers should be avoided to apply in the sandy soils before the rain.