TARBIL project was initiated in 2008 to provide parcel based continuous agro-meteorological parameter prediction, yield monitoring for precision farming and good agricultural practices support. Currently more than 350 automated TARBIL sites are operational over Turkey and the total number is expected to reach 1200. Twenty four parameters are sampled in 10 minute intervals from each site and transferred to TARBIL center for archive and computation of spatio-temporal products. Such high volume of data requires detailed quality control tests to provide necessary information about the condition of data and to filter the corrupted or misleading data from affecting the following automated processes. The ongoing Quality Control System design for TARBIL project is introduced in this study. The quality control tests of range, step, persistence, like-instrument and spatial tests implemented in the QCS design is described. Quality control test applications are detailed with the following quality flagging procedure applied. Finally, the possible benefits of the QCS design output is discussed.