URE-UP MR The MR system derives by the combination of different matrices that determine a physically slow release of nitrogen. The release occurs in different ways and times, thus causing evident advantages both for the crops and for the environment. With the use of URE-UP MR, nitrogen losses due to run-off are limited. Furthermore, the presence in the formulation of elements such as sulfur and calcium highly limits nitrogen losses due to volatilization. URE-UP MR is environmentally friendly and it is not harmful for useful bacterial flora.