The low-input dairy cattle ‘OasYs’ system aims to maximise grazing through the use of diversified multi-species grasslands and annual crops. The aim of this study was to assess whether the management of organic fertilisation or grazing led to deficits or surpluses of N, P and K at plot and rotation levels. We assessed N, P and K inputs and outputs on 6 plots in grassland-crop rotation, 3 of which were in a 7-year grazed rotation and 3 in a 8-year cut rotation. The amounts of herbage grazed were evaluated at paddock level by the Herbvalo method, and used to quantify inputs by faeces. Urinary-N excretions at grazing were assessed by the Urea model. Direct excretion by grazing animals were major inputs of N, P and K at plot level. The 3 grazed plots had a fairly balanced N (-19 to 28 kg ha-1year-1), P (-4 to 3 kg ha-1year-1) and K (-27 to 23 kg ha-1year-1) balance. One cut plot was in balance and the other two in deficit, especially for K (maximum of -100 kg ha-1year-1).