Minimising emissions to water bodies from NW European greenhouses; with focus on Dutch vegetable cultivation

In large parts of the Netherlands surface water quality does not meet the chemical and ecological standards as indicated by the EU Water Framework Directive (WFD). The largest exceedances were found in areas with greenhouse horticulture, flower bulbs, fruit trees and ornamental trees. Several regulations have been implemented to improve water quality in greenhouse areas, leading finally to a target for zero emission of nutrients by 2027 in soilless cultivation and rules to minimise losses in soil bound cultivation. In addition to that an obligation exists to remove plant protection products (PPPs) from drain water by 2018 onwards. For soilless cultivation a Zero Liquid Discharge (ZLD) system gives the best options to reach these goals. For soil-bound cultivation the situation is more complicated and a combination of tools and measurements to help the farmer to tune irrigation to crop demand is most promising. These approaches will lead to a substantial decrease in losses of nutrients and PPPs to surface water. However, it is uncertain whether this will lead to the desired reduction in emissions and the water quality standards of the WFD in 2027. Obstacles might be problems with soil-bound cultivation, leakages in soilless cultivation and sodium limitations in certain crops