In our long-term experiment, we examined the fertilisation and irrigation reactions of two soybean genotypes (Boglár, Pannónia kincse) on chernozem soil for three years (2017, 2018, 2019). Our experimental results showed that, despite the different crop years, the same maximum yields were obtained in all three years (5.4 t ha-1 in 2017, 5.3 t ha-1 in 2018, 5.2 t ha-1 in 2019). As a result of fertilisation, the soybean cultivars provided a moderate yield surplus (Boglár 0–633 kg ha-1, Pannonia treasure 298–967 kg ha-1). The irrigation yield surplus of the examined soybean cultivars was 0–1024 kg ha-1 in the case of half-dose irrigation and 62–1720 kg ha-1 in the case of full-dose irrigation in 2017, while the respective values were 0–1107 kg ha-1 and 0–813 kg ha-1 for 2018. In 2019, with a near-optimal water supply, the yield surplus of irrigation remained moderate (0–512 kg ha-1 and 0–406 kg ha-1, respectively). The specific WUE of soybean was not affected by crop year, the cultivar or fertilisation. As a result of irrigation, WUE values deteriorated, which showed the wasteful water consumption of soybeans under favorable water supply conditions (WUE was 11.8–16.8 kg mm-1 in dry treatment and 9.1–16.1 kg mm-1 in irrigated treatment in the examined crop years).

Keywords: soybean, fertilisation, irrigation, WUE