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Managing nitrogen and carbon to maximise farm performance

We had the pleasure of having Graham Shepherd speak at our farmers’ days in the Tsitsikamma (EC) and Nottingham Road (KZN) in April. Graham is a soil health and regenerative agriculture expert from New Zealand.

We used Graham’s extensive knowledge and experience, and his visual soil health assessment as the foundational theme for the day: Sustainability – Economics and soil power.We explored the topics of soil health and water management, farm nutrient flow, greenhouse gas emissions, and carbon sequestration.

Graham was extremely generous with his time and insight. Both in helping formulate plans to help farmers and in encouraging the Trace and Save research team to explore pertinent topics which will improve the veracity of our sustainability indicators

Graham Shepard giving a field demonstration to farmers using the VSA

Graham Shepherd assessing the activity of root nodules on legumes

Take away points

Graham’s keynote presentation, Managing N and C to maximise farm performance, truly resonated with the audience. Many of the farmers in attendance are already in transition towards sustainable farming while others are not quite there yet. In his very lively, energising session, Graham gave clear tips, and most importantly, actionable suggestions on how to implement valuable strategies that will help improve overall farm performance. The strategies he placed emphasis on include:

  • Reduce fertiliser applications, particularly N fertiliser, as it has negative impacts on the soil biology viz,
    • disruption of mycorrhizal colonisation of roots and therefore the microbiological bridge between plant roots and the soil
    • Creates lazy plants encouraging a shallow root system
    • Reduces the mineralisation and release of plant available N
    • Reduces nitrogen fixation by clover nodules
  • Build soil carbon
    • Plays a key role in maintaining cation exchange capacity and buffering capacity of the soil including the build-up of heavy metals such as lead and cadmium
    • Helps stabilise the soil structure
    • Promotes water infiltration and storage

By combining humour, practical examples, and an informal but highly focused presentation, he demonstrated his knowledge of soil health principles and gave the audience immediate and long-term useful takeaways. True learning took place. The audience left feeling excited and motivated.

In-field Visual Soil Assessment

The infield assessment was one of the biggest highlights of the day. Farmers were taught practical management tips which they can use to assess the health of their soils and pastures.

It is not often that one finds a book that fully acknowledges the science while at the same time provides technical information in a simplified manner which does not necessarily need an expert to interpret. That is what Graham’s VSA book provides, a tool which a farmer can use in the field. The book was used in the field and farmers enjoyed the insight it provided them with.

Watch Graham’s full talk on the day here: Managing nitrogen and carbon to maximise farm performance

Portia Phohlo

Portia is a Trace and Save researcher and has been part of the team that works on the Woodlands Dairy sustainability project for the past 4 years. She studied B.Sc in Agriculture where she majored in crop and soil science at the University of Fort Hare. She went on to do her honors and master’s degree in soil science at the University of the Free State. She is very passionate about soil health and soil microbiology and believes that applying soil health principles will rehabilitate degraded soils.

In her free time, Portia loves catching up on House of Cards and The Walking Dead series. The latter she says she finds it fascinating how a dead decomposed organic material can still be conscious, this actually breaks all rules of microbiology according to her. When she’s not watching that, she enjoys watching motivational videos from Ted, especially ones by her idols Chimamanda Ngozi Adichie and Brene Brown.
Contact Portia on any of her social media platforms or alternatively email her at
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Portia Phohlo

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