Summer heat can significantly impact soil health by disrupting the balance of soil microbes. These tiny organisms are essential for nutrient cycling, soil structure, and crop productivity. Dr Gordon Rajendram, a soil health expert, says, “Understanding how summer temperatures affect microbial populations is key to maintaining healthy soil and good yields.”

Warmer temperatures can initially boost microbial activity, as beneficial microbes thrive in heat. However, this can lead to faster depletion of organic matter, reducing long-term fertility. If the heat becomes extreme, the microbial community may shift, with harmful pathogens outcompeting beneficial microbes. A study in Nature Microbiology highlights that rising temperatures not only influence microbial abundance but also alter the composition of soil microbial communities, which can lead to imbalances that harm soil health (Zhang et al., 2023).

Dry conditions in summer present further challenges. Moisture is critical for microbial life, and dry soils can stress or even kill microbes reliant on water. According to Microbiometer, a lack of soil moisture can shrink microbial populations and reduce their diversity, hindering vital processes like nitrogen fixation and organic matter decomposition. This often results in poorer soil quality, reduced crop yields, and increased reliance on fertilisers.

Farmers can take practical steps to protect their soil microbes:

• Mulch: Apply organic mulch to regulate soil temperature and retain moisture, creating a stable environment for microbes.
• Add organic matter: Compost or cover crops can improve microbial diversity and soil structure, while cover crops also reduce soil heat absorption.
• Irrigate regularly: Maintaining consistent moisture levels prevents microbial stress and supports essential microbial functions.
• Use bioinoculants: These products introduce beneficial microbes to rebalance the soil and enhance fertility, particularly in stressed conditions.

“Fostering soil biodiversity is one of the best defences against the challenges of rising temperatures,” says Dr Rajendram. By adopting these sustainable practices as well as soil and pasture testing, farmers can protect their soil microbes, sustain crop productivity, and promote resilience for the future.

References:

• Zhang, Z., et al. (2023). Nature Microbiology, “Temperature-driven shifts in microbial communities impact soil health.” https://www.nature.com/articles/s41396-023-01470-5
• Microbiometer. (2023). “Seasons of Soil Microbes: How Temperature Affects Soil Microbial Activity.” https://microbiometer.com/blog/seasons-of-soil-microbes

For more information, please contact:

Contact Dr Gordon Rajendram

021 466077

rajendram@xtra.co.nz

www.gordonrajendramsoilscientist.co.nz

Contact Media PA

phillip@mediapa.co.nz

027 458 7724

www.mediapa.co.nz