An Assessment of the Quality of Crop Yield Predictions under Different Degrees of Water Limitation in European Crop Producing Countries

Abstract:

The Fifth IPCC Assessment Report on climate change shows that the frequency and/or intensity of different types of weather extreme events is likely to increase in a number of regions across the globe. The agricultural sector, which plays a crucial role for the livelihood of a large fraction of the world’s population, is particularly vulnerable to extreme events due to its dependency on climate conditions.

Process-based crop models play an important role for translating climate and weather information into agricultural forecasts, both at decadal time scales as part of climate impact assessments and shorter time scales, for examples for seasonal yield predictions as part of early warning systems for harvest failures. A variety of crop models exist, with different degrees of complexity, spatial and temporal resolutions, incorporated chemical, physical and biological processes and mathematical formulations of these processes. Furthermore, crop models differ with regard to the agro-climatic zones and crop types for which they were calibrated and validated. For these reasons, crop models can vary significantly with respect to their suitability for yield forecasts under different climate conditions, geographical regions and crop types.

In this study, we assess the quality of crop yield predictions of the vegetation model LPJmL for four major crops (maize, rice, wheat, soy) under a range of water limitation conditions in Europe, using a high-resolution regional climate data set (0.1 ° x 0.1 °) covering the period 1989-2008. The aim of the study is to examine the degree of uncertainty of yield predictions for different agro-climatic zones and to identify the factors that influence the goodness-of-fit of model predictions. By this, we hope to provide input into further model improvements and to provide guidance for decision-makers on the suitability of yield predictions for different climatic regions within the European continent.