top of page

Wanted: indigenous arbuscular mycorrhizal fungi in agriculture

By Rachel Boucher, M.Sc. student

Part I: The Problem


The agricultural sector is essential to human society; however, its current environmental footprint may limit future production. The conversion of undisturbed ecosystems into farmland has contributed to major biodiversity shifts across the landscape (Średnicka-Tober et al., 2016) and farming is also responsible for 25-33% of the total global greenhouse gas (GHG) emissions (Clark & Tilman, 2017). With a changing climate it is essential to minimize land-use change and mitigate climate change (Tal, 2018). Agricultural land occupies 40% of the land surface on earth (Foley et al., 2005; Tal, 2018). Regrettably, the majority of agricultural land is not managed sustainably (i.e., in a way that ensures that future generations can continue to produce food) (Tal, 2018).

The necessary transformation of agriculture hinges on prioritization of soil health for sustainable crop production as soil is a limited resource (Stockmann et al., 2014). Since the 1960’s global fertilizer use (e.g., nitrogen-based mineral fertilizer) has increased by ~700% further contributing to poor health of soils and nearby aquatic ecosystems (Foley et al., 2005). It is clear the conventional methods of farming leave soil health in a precarious position. This is unacceptable and begs the question: what can be done to transform the industry?


Part II: Transformative Change


An important step towards achieving soil health is the use of arbuscular mycorrhizal (AM) fungi; mutually beneficial, symbiotic partners with plants (Brundrett & Tedersoo, 2018). AM fungi not only improve crop yield and stress tolerance (Johnson & Gibson, 2020); Pellegrino & Bedini, 2014; Pepe et al., 2018) but also contribute to overall soil health. AM fungi can improve soil biodiversity (Asmelash et al., 2016) acting as a pump of C into the soil food web (Antunes & Koyama, 2016). Additionally, AM fungi increase soil aggregate stability, which allows for enhanced soil water retention and resistance to erosion (Mardhiah et al., 2016). All of these benefits make these widespread soil organisms an invaluable resource when considering best practices to sustainably improve soil quality.

Organic farming methods promote AM fungal abundance and diversity (Manoharan et al., 2017) among other benefits such as greater carbon storage, increased soil quality, and preserving biodiversity (Pimentel et al., 2005). The reduction in agrochemical usage in organic farming methods also contributes to reducing eutrophication potentially caused by fertilizer runoff. Studies show that organic agriculture generally results in higher yields than conventional methods under drought conditions due to better soil health; a big advantage in the face of climate change (Pimentel et al., n.d.). However, organic methods typically have lower yields than conventional methods raising questions about its suitability to feed the world (Gomiero et al., 2011). But while less food is produced there are also lower production costs associated with organic farming (Gomiero et al., 2011). Perhaps promoting a culture and an economy based on locally sourced products combined with traditional food storage practices for use where farming is not possible can contribute to making organic farming more mainstream.

There is a lower abundance of AM fungi in conventionally farmed agricultural soils, particularly with intensive tillage which disrupts the hyphae (Säle et al., 2015). No till in association with moderate herbicide use has been shown to increase yields, result in less erosion, and increase water retention in soils when compared to conventional methods of tilling (Tal, 2018). Low till farming can be used in combination with methods such as cover cropping to promote sustainable management of agricultural systems (Page et al., 2021).

At least until genetically catered microbial inoculants become a reality, there is a major need to further the knowledge and develop science-based protocols to cultivate indigenous AM fungi on farms. There are recent studies looking at the potential of using AM fungi in agriculture with consequences on increased tolerance to drought, improved availability of nutrients for crops, and improved crop yield (Jiang et al., 2021; Oliveira et al., 2021; Raklami et al., 2019). In this process, it is vital to encourage knowledge exchange between farmers and researchers. Targeted local conferences create a space for researchers and farmers to learn from one another, ask questions, and expand their knowledge. Sustainable agriculture is context specific; different locations in different ecosystems experience different pressures and therefore will need to utilize different strategies and methods (Ebitu et al., 2021). The farmers know what methods have been working for them, and can help assess novel practices involving AM fungi (Ebitu et al., 2021). Widespread adoption of these methods that focus on soil health can lead to transformation of the agricultural sector so that food production can be ensured for future generations.


References























Comentarios

bottom of page