Agroscope compared crop protection strategies in apple production. Reducing the use of plant-protection products lowered the local ecotoxological risks, but resulted in trade-offs between environmental and economic performance.
Plant protection products (PPPs) are used to protect crops from harmful organisms and thus ensure crop yields and quality. The use of PPPs may also have undesirable effects on the environment, however. Apple orchards produce high yields, but apples are also one of the crops with the highest treatment intensities and the highest amounts of PPPs applied per hectare. On the one hand, this is due to the higher risk of infestation in perennial crops, and on the other hand, because dessert apples should have a long shelf life as they are stored for several months. In addition, the quality requirements expected from trade and consumption are quite high. Therefore, alternative crop protection measures are necessary to reduce the use and risks of PPPs in apple production. Recent developments in innovative crop protection strategies include for example, covers to protect apple plantations from rain (and thus fungal diseases) and insect nets to keep pests out of the orchard. Nevertheless, some alternative crop protection measures require a higher use of materials, energy, labour and financial resources, which potentially leads to other environmental impacts and higher financial costs. Furthermore, alternative crop protection measures are often less effective than chemical approaches, which can lead to lower yields or poorer fruit quality.
Trade-offs between environmental and economic performance in apple production
To identify potential trade-offs in Swiss apple production, three exemplary crop protection strategies were compared with a reference strategy:
- Reference strategy: Average production in Switzerland in 2018 according to the Proof of Ecological Performance (PEP) guidelines;
- Innovative strategy: Reduced use of PPPs with no yield losses, using robust varieties, rain cover, insect netting, alternative PPPs and mechanical weed control;
- Conventional strategy: Maximisation of yields via additional use of PPPs, fertilisers and irrigation;
- Organic strategy: Production according to organic guidelines in terms of PPP and fertiliser use, with yields around one-third lower but double the producer prices for apples.
The comparison of crop protection strategies is based on the calculation of 13 indicators covering both ecotoxicological risks as well as environmental and economic impacts (Fig. 1).
- The innovative strategy enabled a reduction in the use of and risks from PPPs compared to the reference strategy. However, it also led to higher global warming potential and lower farmer’s hourly wage, mainly due to costs and emissions associated with the rain cover and insect netting.
- The conventional strategy achieved a higher farmer’s hourly wage, but also caused higher global warming potential (primarily due to irrigation) and reduced biodiversity.
- The organic strategy enabled a reduction in the use of and risks from PPPs, and achieved a higher farmer’s hourly wage. However, it also led to higher environmental impacts per kg of apples, mainly due to the lower yields.
- The examined crop protection strategies in apple production exhibited different advantages and drawbacks in terms of ecotoxicological risks, global environmental impacts and economic impacts.
- None of the examined crop protection strategies performed better than all other strategies for all of the indicators considered.
- The multi-criteria assessment approach shows which indicators must be improved in the individual strategies to make crop protection in apples more sustainable.
- Significant reductions in local ecotoxicological risks can be achieved with the ‘innovative’ and ‘organic’ strategies, however, this is sometimes achieved at the cost of other environmental and economic impacts.
- A reduction in PPP use with the help of a rain cover and insect netting (‘innovative strategy’) is only profitable with additional incentives, such as higher selling prices for apples.
- Forgoing the use of fossil fuels, could significantly reduce the global warming potential of the ‘innovative strategy’.
- Generally, when optimising crop protection strategies, it makes sense to consider several criteria, instead of focusing on individual aspects.