Ecosystem services in cassava intercropping: a global synthetic review

Intensification and extensification of agriculture are eroding the integrity of tropical ecosystems. As global land comes under increasing anthropogenic management, considering the impacts of management practices on ecosystem services (ES) is essential. Cassava (Manihot esculenta Crantz) cultivation has expanded dramatically in the tropics, currently representing over 25 million hectares managed by millions of smallholders (Fig. 1). Diversification is often cited as a strategy for augmenting the functioning of ES in agricultural landscapes (Brooker et al., 2015; Kremen & Miles, 2012). Despite this, attempts to comprehensively evaluate diversification practices in cassava from an ES perspective remain rare. We conducted a systematic literature review of intercropping in cassava cultivation systems, and employed the concept of ES bundles to evaluate the impacts of diversification on a key set of ES

On-farm diversity offsets environmental pressures in tropical agroecosystems: A synthetic review for cassava-based systems

Peer Revie

Neonicotinoids in global agriculture:Evidence for a new pesticide treadmill?

Overreliance on synthetic insecticides in global agriculture is the outcome of a “pesticide treadmill,” in which insecticide-induced pest resistance development and the depletion of beneficial insect populations aggravate farmers’ pesticide dependencies. Examples of the pesticide treadmill have been witnessed repeatedly over the past seven decades, prompting the question whether the rapid uptake and usage patterns of neonicotinoid insecticides and their associated environmental impact are in accordance with this recurrent phenomenon. We hypothesize a conceptual framework in which treadmills are enforced by enabling or disabling drivers within four domains: pest management decisions at the farm level, characteristics of farming landscapes, science and technology, and societal demands. These drivers then tend to create a self-enforcing pesticide “lock-in.” We then analyze several post-1950s historical case studies with reference to this framework, e.g., those involving sprays of the highly hazardous DDT and methyl-parathion, in which the pesticide treadmill was initiated, sustained, and broken, and compare this with current patterns in neonicotinoid use. Historical case studies further illustrate how treadmills occur in three phases in which (i) a limited number of insecticides are routinely used, (ii) resistance development of pests results in the increased crop injury, prompting increased frequency of applications with a wider range of products, (iii) breaking out of the pesticide “lock-in” by policy change and adoption of alternative technologies that lowered chemical inputs and improved agro-ecosystem functioning. The analysis shows similarities as well as differences between neonicotinoid usage patterns and historic pesticide treadmills, and provides guidance on how to effectively avoid or dismantle pesticide treadmills in global agriculture

Maximizing farm-level uptake and diffusion of biological control innovations in today’s digital era

When anthropologists interviewed Honduran and Nepali smallholders in the mid-1990s, they were told that “Insects are a terrible mistake in God’s creation” and “There’s nothing that kills them, except for insecticides”. Even growers who maintained a close bond with nature were either entirely unaware of natural pest control, or expressed doubt about the actual value of these services on their farm. Farmers’ knowledge, beliefs and attitudes towards pests and natural enemies are of paramount importance to the practice of biological control, but are all too often disregarded. In this study, we conduct a retrospective analysis of the extent to which social science facets have been incorporated into biological control research over the past 25 years. Next, we critically examine various biological control forms, concepts and technologies using a ‘diffusion of innovations’ framework, and identify elements that hamper their diffusion and farm-level uptake. Lastly, we introduce effective observation-based learning strategies, such as farmer field schools to promote biological control, and list how those participatory approaches can be further enriched with information and communication technologies (ICT). Although biological control scientists have made substantial technological progress and generate nearly 1000 papers annually, only a fraction (1.4%) of those address social science or technology transfer aspects. To ease obstacles to enhanced farmer learning about biological control, we describe ways to communicate biological control concepts and technologies for four divergent agricultural knowledge systems (as identified within a matrix built around ‘cultural importance’ and ‘ease of observation’). Furthermore, we describe how biological control innovations suffer a number of notable shortcomings that hamper their farm-level adoption and subsequent diffusion, and point at ways to remediate those by tactical communication campaigns or customized, (ICT-based) adult education programs. Amongst others, we outline how video, smart phones, or tablets can be used to convey key ecological concepts and biocontrol technologies, and facilitate social learning. In today’s digital era, cross-disciplinary science and deliberate multi-stakeholder engagement will provide biocontrol advocates the necessary means to bolster farmer adoption rates, counter-act surging insecticide use, and restore public trust in one of nature’s prime services

Tri-trophic defenses as a central pivot of low-emission, pest-suppressive farming systems

Mitigate+: Research for Low-Emission Food SystemsThe ongoing COVID-19 pandemic has spotlighted the intricate connections between human and planetary health. Given that pesticide-centered crop protection degrades ecological resilience and (in-)directly harms human health, the adoption of ecologically sound, biodiversity-driven alternatives is imperative. In this Synthesis paper, we illuminate how ecological forces can be manipulated to bolster ‘tritrophic defenses’ against crop pests, pathogens, and weeds. Three distinct, yet mutually compatible approaches (habitat-mediated, breeding-dependent, and epigenetic tactics) can be deployed at different organizational levels, that is, from an individual seed to entire farming landscapes. Biodiversity can be harnessed for crop protection through ecological infrastructures, diversification tactics, and reconstituted soil health. Crop diversification is ideally guided by interorganismal interplay and plant–soil feedbacks, entailing resistant cultivars, rotation schemes, or multicrop arrangements. Rewarding opportunities also exist to prime plants for enhanced immunity or indirect defenses. As tritrophic defenses spawn multiple societal cobenefits, they could become core features of healthy, climate-resilient, and low-carbon food systems