Building the macadamia puzzle one insight at a time

Trees that produce good yields of quality nuts form the foundation of a successful macadamia farm. Leaving no stone unturned in his approach, farmer Hentie van der Merwe has proven that paying attention to every factor that influences his crop yields the best results.

- Lindi Botha

Hentie van der Merwe, a macadamia nut farmer in Alkmaar, Mpumalanga, has made it his mission to understand every aspect that can influence the quality and yield of his crop.

“There are hundreds of factors that can make a difference – it’s not just one big thing. Things also change from one year to the next; what worked last year will not necessarily work this year. This is why benchmarking and time in the orchards is crucial,” he says.

Van der Merwe’s orchards range from recently planted trees to those that are 22 years old. His main cultivars are A4 (46%), 816 (31%), and Beaumont (11%), and he achieves an average yield of 3,5t/ha dry nut in shell from the mature trees. This is much higher than the industry average of 2,8t/ha. Further proving the value of his strategy is that some orchards yield up to 6,5t/ha. His overall sound kernel recovery (SKR) is between 40% and 48%, compared with an industry average of 33%.

Managing SKR is a vital part of profitable macadamia nut farming, since this determines the price a farmer will receive for their nuts. This requires carefully timed nitrogen applications, water management, and soil health.

“There are no quick fixes, but a sustained effort over time to improve orchard health brings long-term sustainability,” says Van der Merwe.

LIFE IN THE SOIL

To boost income, macadamia farmers need to aim for thinner shells to maximise the size of the nut kernel. Thus, nitrogen applications need to be carefully considered to balance vegetative growth, without increasing shell thickness.

Van der Merwe, with the help of his consultant James Warrington, has tweaked his fertiliser regime over the years to achieve just that.