Managing macadamias: cutting back brings higher yields

Following rapid expansion between 2014 and 2019, most of South Africa's macadamia nut orchards have reached maturity. The larger trees and denser orchards require a different approach to management in order to get the full yield that mature orchards promise.

- Lindi Botha .

Bigger is not necessarily better. While mature macadamia orchards can deliver higher yields, improper care will result in trees with high input requirements but low outputs.

For Denys Snyman, farm manager at Barberton Valley Plantations in Mpumalanga, regular pruning and root health are central to his care strategy for the farm's 807ha of macadamias. The orchards vary in age, with some over 20 years old.

“The best time to start pruning macadamias is a year after planting,” says Snyman. “This is when you start establishing the strategic frame of the tree by removing unnecessary branches. Branches that are not productive are just consuming fertiliser and water, but don't give anything in return. If the focus is on vegetative growth, yield is reduced, and the tree takes that much longer to get into full production.”

Trees that are left unpruned present multiple problems, all of which reduce a farmer's income.

“Trees that are overgrown and dense prevent sunlight and chemical penetration, reducing yield and quality. By constantly pruning the tree, it is renewed. We get our best nut set on the new flush from branches that were pruned the previous season. Annual pruning is therefore not negotiable. If cash flow is an issue, then I'd rather cut back on fertiliser,” says Snyman.

Optimal pruning centres on more than just cutting windows for better light and chemical penetration. He also focuses on removing branches that have grown vertically, since these increase density without producing nuts.

IMPORTANCE OF HORIZONTAL BRANCHES

“Nuts grow on horizontal branches, so it is important to stimulate horizontal branch growth from the central leader,” he explains.