Sensitivity of silage-maize to climate change in Denmark: A productivity analysis using impact response surface

The sensitivity of silage maize to changing climate in Denmark under varying Nitrogen (N) and undersown catch crop (CC) treatments was investigated using a process-based, soil-plant-atmosphere model; Farm Assesment Tool (FASSET), and the impact response surfaces (IRS). The baseline period consisted of an experiment over a 3-year time period from 2009 to 2011 that was carried out in mid Jutland, Denmark (56°5ʹN, 9°56ʹE 38 m asl). The results indicated that an increase from the average annual temperature (≈6.5 °C) of up to 1.5 °C is beneficial for maize yield. At approximately 8 °C annual average temperature and above, the yield dropped sharply, and any positive impact of varying N treatments and CC was diminished. The maize yield was not as sensitive to precipitation as it was to temperature. The undersown grass in silage maize was not found to be a viable option in relation to warmer climate for all of its benefits were widely overshadowed by the excessive NO3− leaching risk. This study suggested that the warming of the climate along with the projected increase in precipitation in Denmark in the future will greatly challenge the management of N in maize cropping systems. Under changing climate, increasing crop N uptake efficiency by both maize and CC should be targeted as priority. Root growth in this context is an essential feature for the N uptake efficiency. Further research on potential adaptation of different deep-rooted species in the warmer climate that might be suitable as undersown CC is needed.