The data consists of morphological properties of fine roots in old growth forests in Central Amazon. Fine roots younger than three months were sampled using the ingrowth core technique in a large-scale nutrient fertilisation experiment. Morphological properties are given as a mean of the plant community per plot, where five points inside each plot were sampled and separated in two different soil layers (0-10 and 10-30cm). Samples were collected in February 2018, eight months after the nutrient fertilisation started at the AFEX project area in Manaus, Brazil at the Biological Dynamics of Forest Fragments Project (BDFFP/ INPA). The study was funded by NERC, BDFFP (logistical support) and Brazilian government (student scholarship). Full details about this dataset can be found at https://doi.org/10.5285/4ccaab66-2818-41b8-8b31-1a710766c5d6