Landscape context affects the sustainability of organic farming systems

Abstract

Organic agriculture promotes sustainability compared to conventional agriculture. However, the multifunctional sustainability benefits of organic farms might be mediated by landscape context. Assessing how landscape context affects sustainability may aid in targeting organic production to landscapes that promote high biodiversity, crop yields, and profitability. We addressed this using a meta-analysis spanning 60 crop types on six continents that assessed whether landscape context affected biodiversity, yield, and profitability of organic vs. conventional agroecosystems. We considered landscape metrics reflecting landscape composition (percent cropland), compositional heterogeneity (number and diversity of cover types), and configurational heterogeneity (spatial arrangement of cover types) across our study systems. Organic sites had greater biodiversity (34%) and profits (50%) than conventional sites, despite lower yields (18%). Biodiversity gains increased as average crop field size in the landscape increased, suggesting organic farms provide a “refuge” in intensive landscapes. In contrast, as crop field size increased, yield gaps between organic and conventional farms increased and profitability benefits of organic farming decreased. Profitability of organic systems, which we were only able to measure for studies conducted in the United States, varied across landscapes in conjunction with production costs and price premiums, suggesting socioeconomic factors mediated profitability. Our results show biodiversity benefits of organic farming respond differently to landscape context compared to yield and profitability benefits, suggesting these sustainability metrics are decoupled. More broadly, our results show that the ecological, but not the economic, sustainability benefits of organic agriculture are most pronounced in more intensive agricultural landscapes.

The influence of landscape composition and configuration on crop yield resilience

“…Such shifts may make farmers increasingly reliant on natural pest control and thus increase the importance of landscape context. For example, organic farming systems exhibit greater fluctuations in yield than conventional ones, and show an increased dependency on landscape‐mediated ecosystem services (Knapp & van der Heijden, 2018; Smith et al., 2020).…”

“…Effects of natural enemies can also be counter-intuitive, for example by promoting increased movement of pathogen vectors (Clark, Basu, Lee, & Crowder, 2019;Crowder et al, 2019). The complexity of these interrelationships means that positive effects of semi-natural habitat on natural enemy abundance and richness do not always translate to improved pest regulation or enhanced yields (Karp et al, 2018;Martin et al, 2013Martin et al, , 2019Mitchell, Bennett, & Gonzalez, 2014;Smith et al, 2020;Tscharntke et al, 2016). By examining effects on yield of a single crop, we focus directly on the outcome of this suite of complex interactions and our results show that amount and proximity of semi-natural habitats have an overall positive effect on yield stability and resistance.…”

Ecological and Nutritional Functions of Agroecosystems as Indicators of Smallholder Resilience

“…Future frameworks developed for locations where fine-scale data is more freely available would benefit from empirical tests to better understand and incorporate the role of institutional and landscapelevel factors on agroecosystem-level social, ecological, and nutritional processes. Interactions between landscape context (e.g., Smith et al, 2020), governance, and farm management decisions affect the livelihoods and resilience of millions of smallholders.…”

Orchard Management and Landscape Context Mediate the Floral Microbiome of Pear

“…Agricultural landscapes are often spatially heterogeneous. Accruing through shifts in land tenure over time, this heterogeneity reflects a landscape’s composition and configuration (Fahrig and Nuttle, 2005; Fahrig et al ., 2011; Smith et al ., 2020). Specifically, crop production occurs on patches of land that exist within habitat mosaics containing patches of the same crop, alternative commodities, and semi-natural vegetation.…”

“…Such variation in land cover around a crop field may strongly affect local abiotic and biotic conditions. Most studies assessing the effects of spatial context, however, have focused primarily on plants (Smith et al ., 2020) and animals (Karp et al ., 2018), but effects of landscape-level drivers on plant-associated microbiomes has received less attention. This is a problematic knowledge gap as microbes often disperse over long distances, and studies show that spillover of microbes from agricultural into natural habitats is affected by landscape context and dispersal ability of individual taxa (Bell and Tylianakis, 2016).…”