Development of a quick on‐farm test to determine nitrate levels in soil

Crop management can be optimized and nitrogen (N) losses can be reduced with a better knowledge of soil‐nitrogen availability, especially if this information becomes directly available on‐site in a fast and cost‐effective way. In this paper, simple on‐farm methods to determine nitrate‐N in field‐moist soil samples immediately after sampling are described. The procedures include volumetric soil sampling, extraction based on manual shaking with tap water as universally available extractant, filtering soil/extractant mixtures on‐site, on‐site determination of the soil water content, and reflectometric nitrate measurements based on test strips. Using correction factors can compensate the impact of the temperature during the final nitrate measurement. An excellent agreement was found between the developed quick‐test procedures and the standard laboratory procedure. The proposed quick‐test has great potential to enable economical savings for farmers as well as benefiting the environment.