Ecological redesign of crop ecosystems for reliable crop protection. A review

To attain food security, we must minimize crop losses caused by weed growth, animal herbivores, and pathogens (or “pests”). Today, crop production depends heavily on the use of chemical pesticides (or “pesticides”) to protect the crops. However, pesticides are phased out as they lose efficiency due to pest resistance, and few new pesticides are appearing on the market. In addition, policies and national action programs are implemented with the aim of reducing pesticide risks. We must redesign our cropping systems to successfully protect our crops against pests using fewer or no pesticides. In this review, I focus on the principles for redesigning the crop ecosystem. Ecological redesign aims to enhance ecological functions in order to regulate pest populations and diminish crop losses. Exploring ecology and ecosystems plays an important role in this transition. Guiding principles for redesigning the cropping system can be drawn from understanding its ecology. Ecosystem and community ecologists have identified four principal ecological characteristics that enhance the biotic regulation of ecological processes across ecosystems: (i) advanced ecosystem succession through introducing and conserving perennial crops and landscape habitats; (ii) reduced disturbance frequency and intensity; (iii) an increase in both managed and wild functional biological diversity, above and below ground; and (iv) matched spatial extent of land use (e.g., crop field size) with that of ecological processes (e.g., dispersal capacity of predators). I review the practices that link these ecosystem characteristics to crop protection in grain commodity cropping in both the crop field and the agricultural landscape. The review brings forth how basic understandings drawn from ecosystem and community ecology can guide agricultural research in the redesign of cropping systems, ensuring that technologies, breeding, innovation, and policy are adapted to and support the reshaped crop ecosystem.