Fig. 1: Average annual N, P and K fertilizer inputs, yields, nutrient balances and nutrient use efficiencies for wheat, sunflower and maize crops in Ukraine over 1980, 1986, 1990 and 2000–2023.

Fertilizer inputs (a) show the combined amounts of synthetic and organic NPK applied; yields (b) represent harvested crops removed from the field; nutrient balances (c) indicate the difference between nutrients in inputs and those in harvested yields (see “Methods” for details); nutrient use efficiencies (d) are the ratios of nutrients in harvested yield to nutrient inputs (see “Methods” for details). Annual inorganic N deposition (Supplementary Fig. 5) and annual N fixation by free-living organisms (assumed to be 5 kg N ha⁻¹ yr⁻¹)³⁷, both not shown in this figure, were used as N inputs for N balance and N use efficiency calculations (see “Methods” for details). To avoid risk of soil nutrient mining, 90% fertilizer use efficiency is shown as an illustrative benchmark target (see “Methods” for detail). Horizontal dashed lines represent the final year of USSR era (1990), a distinct drought year (2020) and the beginning of the large-scale war in Ukraine (2022).