TReNDS is a research project on Transport and Reduction of Nitrate in Danish landscapes at various Scales. Prompted by the Danish Commission on Nature and Agriculture, new regulation strategies are being developed in Denmark based on spatially differentiated N-regulation. Higher N-applications can be allowed in areas with high natural reduction of nitrate in the groundwater and riparian zones. This approach is novel and will have large socio-economic impact. The TReNDS project started Jan. 1, 2015, and runs for four years until the end of 2018. Eight research groups (including one Canadian, one Australian, and two from the United States), a Danish consulting company, and two Danish SMEs and two Danish public authorities are involed in the project.