Mix it up

Healthy soil requires to mix it up: maximising crop diversity can maximise soil health. Ecosystems benefit from diversity; every species has its role and its contributions to the entire system. Moreover, increased diversity can enhance soil fertility and resilience against pests, diseases and weeds. This means … increased diversity can reduce input costs while improving crop outputs! 

While minimising soil disturbances is critical to enhance soil biodiversity, above-ground and soil biodiversity benefit greatly from crop diversification. Crops can be diversified over time through crop rotation (Khangura et al. 2023), or simultaneously by mixed cropping, planting non-crop plants between crop rows and/or at field margins (LaCanne & Lundgren 2018)

Why it matters?

Maximising crop diversity matters. Firstly, plant diversity can break the pest-disease-weed cycle (Khangura et al. 2023). The more diverse the ecosystem, the more ‘niches’ it can provide to house a wider variety of invertebrate, insect, bacteria and fungi species. Thanks to the diversity and richness of these species, they deploy natural processes to outcompete threatening weeds and pests, such as competition, and predation (LaCanne & Lundgren 2018). In contrast, monoculture reduces biodiversity and community structures which are linked to higher infestations of pests and weeds because they do not inhabit these natural outcompeting processes (LaCanne & Lundgren 2018). In turn, they require more and specific pesticides and herbicides. Together with reduced biodiversity, this reliance on synthetic insecticides and herbicides leads to pest and weed persistence and resurgence, creating a negative feedback loop (Lacanne & Lundgren 2018).

Secondly, maximising crop diversity can enhance soil fertility. Above ground diversity can enhance below ground microbial diversity, and functioning. When the soil microbiome flourishes thanks to the diversified crops above ground, they cannot only increase the levels of soil organic carbon, nitrogen and microbial biomass because of increased abundance, activity, and diversity (Kharunga et al. 2023), but also increase the plant resource us efficiency by enhanced functioning and enzyme activity (Daryanto et al. 2018; Feng et al. 2021). Legume cover crops are specifically desirable because of their low carbon-nitrogen ratio, enabling them to fixate significant levels of nitrogen to the main crops (Kharunga et al. 2023).

The benefits of diversity

Diversity is linked with resilience, strength and health in various areas of life, and that is not different to plants. Greater biodiversity can enhance natural pest and weed management while decreasing the use of synthetic pesticides and herbicides (Hilimire 2011; Lacanne & Lundgren 2018). LaCanne and Lundgren (2018) found that pests were 10 times more abundant on conventional corn farms compared with regenerative farms. Hence maximising crop diversity maximises soil resilience.

This increased natural pest and weed management leads to additional benefits. Firstly, it reduces the need for synthetic inputs which decreases associated costs and increases biodiversity. This also improves runoff water quality. In addition, crop diversification can increase soil carbon, nitrogen and microbial biomass which enhances soil fertility (Kharunga et al. 2023). This in return reduces the need for synthetic fertilisers with the now known benefits of better runoff water quality. Moreover, this also reduced greenhouse gases and costs generated by the synthetic fertilisers. Add some legume cover crops in the mix, and these effects can be strengthened thanks to their potential to fix nitrogen (Kharunga et al. 2023). Lastly, this decreased pests and weeds, and increased soil fertility may increase the farmer’s revenue by increasing soil fertility and crop yield while reducing costs of chemical inputs.

The Journey to maximised crop diversity

In a nutshell, maximising crop diversity can maximise pest-disease-weed resistance and resilience, while enhancing soil fertility and farmer’s revenue. As with all agricultural practices, the effects depend on soil, climatic, environmental and agronomic variables, as well as the specific cover crop used (Wagg et al. 2021). These benefits can be enhanced in combination with other regenerative agricultural practices that enhance the soil microbiome (Kharunga et al. 2023).

Now that we have begun the journey towards saving the health of our soils by minimising soil disturbance, the next step is to measure and monitor that progress. This requires accurate and detailed soil data for farmers to map out the precise soil characteristics, health indicators and the best practices to improve them. These data can qualify and validate that less is more. To learn more about CAS’ soil data intelligence solutions, contact us or explore our website and continue reading.