Korea's protected horticulture is rapidly increasing in scale due to various advantages such as year-round harvesting, labor savings through automation and shortened culture period, and greater income generation. This study was conducted to investigate the impact of protected horticulture on water quality. The results of this study are expected to provide basic data contributing to improvements towards sustainable agriculture and eco-friendly design of protected horticulture complex. The average T-N and T-P loads from vinyl greenhouses were 286.55± 143.98 mg/L and 59.14±13.77 mg/L, respectively and those from glass greenhouses 380.68 ± 150.41 mg/L and 61.85±20.72 mg/L. The annual discharge of wastewater derived from the monthly discharge from the horticulture greenhouses were estimated at 2597 ton/ha, with the annual phosphorus load amounting to 155.3 kg/ha. The average T-N and T-P loads in the tested greenhouse effluents were in excess of 8.3- and 13.5-fold the standards for the Korean wastewater plant effluent. The waste nutrient solution discharged from a protected horticulture complex can cause water contamination. Therefore, there is a need to conduct follow-up research using a water purification system or a trench method to develop a eco-friendly protected horticulture complex for sustainable agriculture.

Presently, aquatic plants are used for the water purification in inland water. This study was carried out to investigate the water purification effect of aquatic plants, Oenanthe javanica and Typha angustata. The experiment was conducted in outdoor flowing water was conducted for ten days. Water quality was measured in terms of water temperature, COD(chemical oxygen demand), SS(suspended solids), Total N, Total P. The results of field experimentation showed that hydraulic retention time was the earliest in July and August 2003, and there were not any particular changes of monthly water temperature in inflow water and outflow water. As we look at the changes taken place in inflow water and outflow water throughout the whole experiment period, the change of water quality in summer was salient, especially SS removal ratio showed distinguished change as 25%, when the pebble filter and aquatic were attached to it. The removal rate of COD, total N total P were 14.7%, 8% and 9%, respectively. In relating the length of water extension to the change in water quality, the water quality tended to get lower generally in proportion to hydraulic retention time.