Validating aquacrop model for rainfed and irrigated maize and soybean production in eastern croatia

Abstract

In this study, the AquaCrop model was used to quantify climate change impact on yield and net irrigation in maize and soybean production. Daily observed climate data (1961–1990) from Osijek weather station were used for past climate simulation, and output data from ECHAM model were dynamically downscaled under two IPCC SRES scenarios (A1B, A2) for two integration periods 2041–2070 and 2071– 2100. The soil properties and crop data were presented from 6-year-long (2010–2015) field study of the Agricultural Institute in Osijek, Osijek-Baranja County. The climate results showed expected rise in air temperature up to 5 ºC and significantly lower precipitation up to 43.5%. According to results from the AquaCrop model, there is no change in maize yield in non-irrigated conditions, while in irrigated conditions there is a yield increase of 1.4 t ha-1 of dry matter (dm), with 80 mm higher net irrigation in comparison with the 1961–1990 period. As for soybean production, the increase in yield is expected in both non-irrigated and irrigated conditions. The yield increases up to 1.9 dm t ha-1 in irrigated conditions with 90 mm higher net irrigation in comparison with the 1961–1990 period. As for crop water indices, in non-irrigated conditions the water use efficiency (WUE) has a trend to decrease in the future, while in irrigated conditions it can slightly increase. Irrigation water use efficiency (IWUE) showed significantly higher increase in irrigated maize and soybean production.