Farmers and scientists in Mali are learning first-hand how satellite technology can be used to interpret crop performance and alter decision-making on-farm.The study measures the sensitivity of satellite sensors to on-farm fertility treatments applied to five locally important crops in Mali’s cotton belt: cotton, maize, peanut, pearl millet and sorghum. Vegetation index sensitivity to fertilization is analyzed at the field scale, along with the amplitude and timing of strongest plant responses. Spatial variance components are quantified with respect to fertilization