From 2027, Dutch greenhouse horticulture must grow emission-free: water from the greenhouse may no longer flow to groundwater or surface water. Together with a number of partners, the Business Unit Greenhouse Horticulture and Flower Bulbs of Wageningen University & Research (WUR) is developing a handy nitrate sensor with which growers can check whether their greenhouse is 'leaking' water.
Nitrate is fairly easy to measure. Tracing other elements – like phosphate or ammonium - is much more complicated. When a high concentration of nitrate is being found in a ditch next to a greenhouse, it means water is leaking from the greenhouse, together with other substances.
Measuring quickly, easily and cheaply
However, there are no cheap and handy meters to measure the nitrate content in water. That is why WUR and a number of partners have decided to develop one themselves. The aim of the new meter is that growers can quickly, easily and cheaply measure the nitrate content in the surface water around their company. If the concentration in a location is relatively high, then there is probably a leak in the greenhouse nearby.
Real-time monitoring nitrate in drain water
With the new meter, growers can also check the process water in the greenhouse. As a result, they quickly see how much nitrate is present in drain water, and therefore how many fertilizers plants absorb. This may be a reason to adjust the fertilization. Growers currently have to send a sample of the drain water to a lab, which takes a relatively long time. The new nitrate meter is also useful for water boards: they too can quickly check the quality of the ditch water.
The study lasts four years. For the investigation, a number of available nitrate meters will be further investigated for accuracy, among other things. This leads to a package of requirements for a new handheld meter. In the last year of the four-year study, a new meter is developed together with a commercial party.
The research is funded by Top Sector Horticulture and Starting Materials, Knowledge in your Greenhouse (KIJK) and STOWA. Partners are IMEC, Acacia Water, Hoogheemraadschap Delfland, AKVO and Fixeau.