Crop planting date matters: Estimation methods and effect on future yields

Abstract Productivity of arable lands highly depends on the management techniques and their timing. Climate change urges the need for adaptive management tools, such as methods for optimization of planting date (PD). In existing crop models PD is usually specified by the user as a fixed date or through a set of rules which depend on diverse environmental conditions. However, validated rules of PD calculation are rare in the existing literature. In this study we strived to develop methods that could reliably estimate the PDs based on soil temperature and soil moisture, as well as to provide tool for PD projections under climate change. PD data from 294 agricultural enterprises in Hungary during the period from 2001 to 2010 were used to validate the PD methods. Effect of climate change on the timing of PD was evaluated using an ensemble of 10 climate change projections. Meteorological and soil data were obtained from the Open Database for Climate Change Related Impact Studies in Central Europe (FORESEE) and Soil and Terrain (SOTER) databases. The 4M crop model was used for crop yield simulations. Relative to the present day conditions, our analysis predicts a shift to earlier PDs for maize (approx. 12 days) and later PD for winter wheat (approx. 17 days) for the 2071–2100 period. The results indicated that maize PDs should be changed according to the earlier start of the growing season in spring. In contrast, currently used PDs should be preserved for winter wheat to avoid climate change related yield loss. Our analyses showed that the proposed PD estimation methods performed better than other eight tested methods. The advantage of our novel rules is that they could be applied for other crop models, as well.