This document describes the measurement of ancillary vegetation variables at ICOS ecosystem stations in croplands. These variables are Green Area Index (GAI), Aboveground Biomass (AGB), and litter biomass. In summary, they are measured for the following aims and with the following methods: - GAI is measured to explain seasonal variation in ecosystem-atmosphere fluxes and is measured either directly by destructive sampling or indirectly with a linear ceptometer. Indirect measurements are compared against direct measurements from destructive sampling once per growing season, at peak GAI. - AGB is measured to estimate yearly Aboveground Net Primary Productivity (ANPP) and lateral carbon flow through harvest. AGB is measured by destructive sampling. In case of tubers and root crops, also the belowground biomass of tubers and roots is measured. - Litter biomass is measured to correct the yearly ANPP estimated from AGB and is measured with litter traps. Litter biomass only has to be measured in crops where deemed relevant. Litter refers also to harvest residues, which are measured to correct the lateral carbon flow estimated from AGB at harvest for the material left on the field. Harvest residues are measured using collection plots. Litter biomass, including harvest residues, is only a mandatory variable for Class 1 sites. This document is structured in four different sections with the aim to facilitate the use and application: - Measurements: in this section the sensors, setup and methods to correctly collect the data and info are described. It includes sub-sections on sensors characteristics, practical indication for the setup/collection, info on the sampling design and guidelines for the installation/sampling also respect to other sensors/measurements - Maintenance: in this section all the maintenance and calibration guidelines are described, including the general timeline. - Submission: it is the section related to the data preparation and submission to the ETC. It includes the list of all the parameters, the correct formatting and the way to submit them to the database. It is linked to the BADM system needed to submit the metadata and not continuous measurements - Processing: this section is for internal use of the ETC and describes the processing applied to the single variable/info/sample submitted. It is important to remind that the exact application of the protocol at site level is also discussed with ETC in order to find agreed solutions for specific cases. If a specific part is relevant only for a specific ecosystem or station Class this is also reported in the document.