In a polyfactorial duration experiment we examined the interaction of crop years with different water supply (dry = 2007, average = 2015, favorable = 2019) and agrotechnical elements (irrigation, fertilisation, crop rotation) in maize as a model crop, on chernozem soil, in the Eastern Hungarian region (Hajdúság). The maximum yield level of maize was determined by the given crop year, which was further modified by different agrotechnical factors. The maximum yield varied between 4.3–8.0 t ha-1 (non-irrigated) and 8.6–11.0 t ha-1 (irrigated) in the dry year, while in the average year it was 10.1–12.8 t ha-1 (dry) and 12.7–13.9 t ha-1 (irrigated), and in years with favorable water supply it varied between 12.8–13.9 t ha-1 (dry) and 13.5–13.9 t ha-1 (irrigated). The optimal fertiliser dose was significantly determined by crop rotation. The optimal fertiliser dose was N180-240+PK in monoculture, N120-180+PK in biculture and N60-120+PK in triculture. The yield surplus from irrigation was determined by the water supply of the given crop year. The yield surplus from irrigation varied between 2.5–5.9 t ha-1 in dry years, 1.0–2.7 t ha-1 in average years and 0.5–1.0 t ha-1 in years with favorable water supply, depending on crop rotation. Our long-term experimental results demonstrated the close, interactive effect of nutrient×water supply. The yield surplus of maize fertilisation in the dry year varied between 1.3–1.6 t ha-1 (non-irrigated) and 2.5–3.4 t ha-1 (irrigated). The yield surplus from fertilisation ranged between 1.6–5.6 t ha-1 (dry) and 2.3–7.5 t ha-1 (irrigated) in an average year, and 1.8–4.7 t ha-1 (dry) and 1.1–5.0 t ha-1 (irrigated) in a favorable year. The water supply of the crop year also affected the water utilization efficiency of maize. WUE values varied in the range of 12.6–40.5 kg mm-1 in the dry year, 19.5–50.2 kg mm-1 in the average year, and 25.1–43.5 kg mm-1 in the favorable year under non-irrigated conditions. As a result of irrigation, the water utilization of maize deteriorated (WUE values in the dry year: 13.1–27.6 kg ha-1, in the average year: 14.7–39.3 kg mm-1, in the favorable year: 20.1–33.2 kg mm-1).

Keywords: crop year, maize, irrigation, fertilisation, crop rotation, WUE