Farm Table says:
Significant increases in the yield of wheat have been achieved during the last half-century by changes in agronomic practice in particular the increased use of synthetic fertilizers and pesticides and the selection of cultivars that are suited to these conditions.
Sustainable arable crop production can be achieved by identifying the key areas of production in terms of nutrient management and crop protection to achieve long-term sustainable yields. The aim of this study was to determine the effect of different production system components, i.e. year, previous crop, rotational position together with crop protection (CP) and fertility management (FM) practices on the yield and quality (protein content and hectolitre weight) of winter wheat grown as part of the Nafferton Factorial Systems Comparison (NFSC) long-term field trial since 2004.
The study separates the effects of crop protection and fertility management in organic and conventional production systems.
• A yield of wheat was 40% lower from an organic production system when compared to a conventional system.
• Fertility limited the yield and protein content in the organic management system.
• Preceding crop had a significant effect on the performance of organic wheat and disease levels observed.
This emphasizes the role that grass/clover as a preceding crop has to nitrogen supply in an organic production system especially from the decomposition of belowground residues.
• The use of higher organic fertilizer based N-inputs and
• the use of organic fertilizers with a greater content of plant available N (e.g. chicken manure pellets and biogas digestate) may increase both yields and protein content.
However, the maximum organic fertilizer based N-input permitted under current environmental legislation in any one year is 250 kg N ha−1 and average annual inputs over the whole rotation are not permitted to exceed 170 kg N ha−1. The pRDA showed that although fertilization had the greatest effect on yield, quality and disease there was also a considerable effect on crop protection and the environment.
It was not just conventional fertilizer making the differences, but a product of management, weather, and previous crops. Future research to improve yields in organic production systems should therefore focus on improving the fertiliser use efficiency from organic fertilizers and fertility building crops via breeding (selection of varieties with higher nitrogen uptake efficiency from organic fertilizer inputs) and agronomic approaches (e.g. use of split-dose application of organic fertilizers and/or the use of organic fertilizers with a higher content of readily available forms of N).