How can different crop strategies improve the quality and safety of food? (subproject 3)
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The potential of organic and ‘low input’ methods for high quality, high safety and economically viable crops is far from fully exploited. Consequently, crop strategies are being scrutinized, namely interactions between soil fertility and plant health, nutrient release characteristics and nutrient uptake in organically managed soils, organic manuring and food safety as well as pest and disease control. |
In organic systems (and to a lesser extent in ‘low input’ systems), soil fertility management and its effect on plant health and eventually on yield, quality and food-borne pathogens are major issues to be addressed by research. The long-term use of organic matter based fertility inputs was shown to significantly increase the efficiency of organic production (input/output ratio) and also to suppress both seed-borne and foliar diseases.
Long-term field experiments
In order to analyse the wide range of interactions responsible for such effects and to enable farmers to make the best use of them, long-term field experiments are crucial. Several work packages of both subproject 2 and 3 use long-term experiments in various parts of Europe, to facilitate the development of improved nutrient models and precision farming systems.
As a main result it can be concluded that the potential of manure and compost based systems for improving crop yields and crop quality is still high. Wheat as a model crop showed the potential of fertility management improvements in order to increase both yields and quality.
Field trials in the UK in 2005 demonstrated how improved fertility management increased yields of winter wheat by 6 to 33% (depending on the cultivar) and in summer wheat by (-4) up to 14%. Novel wheat varieties selected especially for ‘low input’ conditions produced protein contents between 11 and 12%, while the reference cultivar remained at 9.2%.
On the other hand, soil fertility is only one factor affecting disease suppression, as many interactions with other agronomic factors and soil properties occur. These will be analysed in the second half of QLIF.
Manure and risk of transfer of enteric pathogens
The use of manure in organic farming systems – while having significant benefits for soil structural stability, biological activity and overall fertility – has also been criticized because it may increase the risk of transfer of enteric pathogens into the food chain. These aspects were addressed by several field experiments. Enteric pathogens were found in lettuce at extremely low levels and independently of whether organic manure or mineral fertilizers were used. The most efficient way to reduce pathogen loads was shown to be the composting of manure.
Preventative protection strategies
Crop protection in organic and ‘low input’ systems has remained a bottleneck and affects both the cost of these production systems and the quality (and safety) of food products.
The integrated use of preventative protection strategies (rotation design, fertility management, environmental diversification) are the basis of weed, pest and disease control in low input crop production. Such strategies minimize the need for crop protection products.
In the QLIF project wheat, tomato, onion and apples were chosen as model crops to develop (a) a wide range of novel preventative crop protection techniques and approaches and (b) integrate preventative techniques with crop protection methods based on more benign forms of intervention (companion plants, biological control agents, elicitors and plant extract based products). Results so far are extremely promising and substantial progress can be expected when transferred into practice.
For a more detailed description of work under subproject 3 see Tamm et al., 2007.
Reference
Tamm, L., Köpke, U., Cohen, Y. & Leifert, C. (2007) Development of strategies to improve quality and safety and reduce cost of production in organic and ‘low input‘ crop production systems. In: Niggli, U. et al. (Eds) (2007): Proceedings of the 3rd International Congress of the European Integrated Project Quality Low Input Food (QLIF). FiBL, Frick, Switzerland |
