dr. A (Aart) van der Linden

In 2007, I started a BSc in Plant Sciences at Wageningen University, and continued with an MSc in Crop Sciences in 2010. During my studies I specialised in crop modelling and crop management. Quantification and analysis of yield gaps were important components in both the BSc and MSc.

After graduation in 2012, I started a PhD research in the Animal Production Systems group and the Plant Production Systems group of Wageningen University. This research aimed to apply the methods for quantification and analysis of yield gaps, which are widely used in crop sciences, to livestock production. In the crop sciences, yield gaps are quantified based on concepts of production ecology. Concepts of production ecology distinguish three production levels: potential, limited, and actual production. I specified concepts of production ecology for livestock production in more detail than previously done, and developed a framework to calculate potential and feed-limited livestock production.

Next, a mechanistic model to simulate potential and feed-limited production of beef cattle was developed (LiGAPS-Beef), which allows to quantify and analyse yield gaps at herd level. This model was validated with experimental data, and turned out to simulate average daily gain fairly well. Integration of feed crop and livestock production started after the developement of this model. Combining feed crops and cattle allows to quantify beef or live weight production per hectare (used for feed crops) per year. We integrated crop and livestock models to simulate beef production in the Charolais region of France. This approach allowed to quantify yield gaps of beef cattle per hectare per year, and to identify the major biophysical factors contributing to the yield gap in the Charolais region. Furthermore, I investigated the effect of climate change on beef production in the Charolais area. The PhD thesis that came forth of this research provided a generic method to assess and analyse yield gaps in livestock systems and feed-crop livestock systems.

My current focus is to apply the generic method described in the thesis to more case studies, including developing countries, and to extend the modelling to dairy cows as well. My current research projects are described below.