This thesis shows that benefits from soil organic matter for crop production cannot be taken for granted. If European policies aim to include benefits from soil organic matter for crop production, focus should be on areas with more extreme or harsh environmental conditions, or cropping systems with more specialized or horticultural crops rather than cereals.
These findings are based on results from twenty long-term experiments and a large scale farm survey among more than 1000 farmers. Experiments show that crop yields can benefit from organic inputs (especially when cultivated on sandy soils or in wet climates or with root and tuber crops), but not necessarily so. Compared with using only mineral fertiliser, the use of organic inputs (such as animal manure or crop residues) did not increase average crop yields. The farm survey revealed that when using organic inputs farmers perceive a trade-off between improved soil quality on the one hand and increased pressures from weeds, pests and diseases and financial costs on the other hand.
Recently, much attention is given to the promising potential of soil organic matter in agricultural soils to mitigate climate change and increase food security. With her PhD thesis, Renske Hijbeek aims to improve our understanding of the role of organic inputs and soil organic matter for crop production in contemporary arable farming in Europe.