Facing persistent El Niño climate risks, Southern African farmers are turning to precision tools to trim input costs without losing crop yield. Dr Michael Southwood, founder of the Agri Vision Foundation and organiser of the SADC Plant Nutrition Symposium, explains how precision measurement tools cut back on water and fertiliser use while protecting long-term soil health.
Precision agriculture is no longer about high-cost guesswork; it centres on actionable, real-time data that directly informs daily management decisions.
When optimising irrigation, Southwood says, managing water is fundamentally about managing oxygen levels in the root zone. Over-irrigating saturates the top 30 to 40 centimetres of soil, where most feeder roots sit, creating anaerobic conditions that inhibit root development and soil biology.
“If you over-irrigate, obviously, there will be a lack of oxygen, and you’ll not have the continuous formation of new roots,” Southwood cautions.
By utilising soil moisture probes across 10cm depth increments alongside drone technology and NDVI satellite imagery, growers can precisely monitor soil water capacity and detect early crop stress before visual symptoms appear.
Preventing over-fertilisation through real-time sap testing
Over-applying nitrogen remains a common and costly pitfall in commercial crop management. Southwood points out that roughly seven out of ten crop quality issues stem from excessive nitrogen, which induces soft, lush growth that leaves plants vulnerable to biotic and abiotic stress.
Rather than relying solely on dry leaf lab analysis, which often reflects past nutritional history, Southwood advises using on-farm sap meters to track nitrogen, electrical conductivity (EC), and Brix levels twice weekly in the field.
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“You can on-farm, in real time, actually squeeze the sap out of either fruit or leaf petioles, and that would identify the nutrient makeup in the plant sap,” Southwood explains.
Tracking real-time sap metrics empowers farmers to fine-tune nitrogen applications continuously, allowing operations to reduce total unit inputs without lowering harvest quality or volume.
Precision placement and localised fertigation
Modern input management is shifting away from broad, whole-hectare applications toward targeted placement. Using advanced dripper technologies or controlled-release formulations, growers can band-place nutrients across just 15% to 20% of the field surface.
This localised approach prevents soil brackishness, minimises long-term soil acidification, and preserves microflora health.
Southwood emphasises that farmers looking to adopt precision practices should start small, beginning with a single well-performing block and establishing on-farm datasets to guide future inputs.
For producers looking to explore these cutting-edge application methods and technology in depth, he invites industry professionals to attend the upcoming SADC Plant Nutrition Symposium.
“If you want to find out more, you must join our fertiliser symposium,” Southwood encourages, noting that the event will feature technical presentations on advanced dripper tech and precision nutrient formulations.
Joining the regional conversation
The SADC Plant Nutrition Symposium takes place on Thursday, 19 and Friday, 20 November 2026 at the Protea Hotel, Technopark, Stellenbosch, with online access also available for regional delegates.
To secure delegate bookings or request programme details, contact Marlise Coetzee at Symposium@southerncrosstrust.com or reach out via WhatsApp at 082 261 1598.
Tickets and online access are now available.
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