Ontwikkeling en evaluatie van een handzame nitraatmeter voor drainage- en oppervlaktewater in de glastuinbouw

By 2027, greenhouse horticulture in the Netherlands must grow almost emission-free. The surface water quality in horticultural areas is already improving, but unwanted leaks are currently still a problem. Measuring surface water quality by growers themselves on and around their greenhouse could provide more insight into disasters. Measuring nitrate in surface water seems to be a good method to detect fertigation water in surface water due to leaks. Research has therefore been conducted into a nitrate meter that growers can easily use themselves. Based on desired technical and practical specifications, handheld meters available on the market and prototypes from research have been assessed for, among other things, suitability, accuracy, ease of use and cost price. A practical evaluation was carried out at six greenhouse growers using the handheld meter found to be most suitable. The meter has been found to be handy, robust,and sufficiently reliable to detect increased concentrations of nitrate in surface water. The meter has a large measuring range, allowing measurements to be made in surface water as well as in nutrient solutions and drainage water. To detect leaks, the surface water must be checked weekly. The accuracy of the meter is less than that of laboratory analyses, but the low purchase price and operational costs are such that the use of the hand meter is more economical as soon as more than one measurement is carried out per week.