The last two decades – evolution of macadamia orchard management in South Africa.
By Philip Lee
Many of the changes in horticultural management practices over the last two decades, and indeed the two decades before 2005, were precipitated by fluctuating world market prices for macadamia nuts, as well as the increasingly demanding quality requirements dictated by the markets.
During my career in macadamias the industry has seen four highs and four lows. From $13 in 1988 to $5,5 in 1991 to $9,9 in 1995 to $6,4 in 2000 to $11,4 in 2005 to $6,6 in 2007 and then the unprecedented rise to $18,4 in 2019 back to $8 in 2023, all prices for macadamia kernel imported into the USA expressed as $/kg kernel.
Growers respond to the negative impact on profitability during times of low prices by doing whatever they can to reduce production costs, including reducing fertiliser and agricultural chemical usage and postponing planned capital expenditure (new/replacement tractors, other agricultural machinery and dehusking/drying facility upgrades/expansion), and the industry sees a significant reduction in new orchard establishment and new tree orders at nurseries.
While the Chinese market provided a convenient outlet for our crop as Nut-In-Shell (NIS) exports, growing from around only 500 tons in 2005 to some 40 000 tons in 2025 and comprising mainly nuts of the Beaumont (HAES 695) cultivar, Chinese buyers have become increasingly quality conscious in the last few years, preferring cultivars with higher sound and whole kernel recoveries, resulting in a considerable reduction in demand for Beaumont NIS in this market. The relatively high proportion of half kernels produced by Beaumont make it less desirable for cracking for the kernel market as well, causing a dramatic reduction in demand for Beaumont trees from nurseries, which have had to pivot to cultivars like 816 and A4 with better quality characteristics since 2020.
Two decades of fast growth but no commensurate yield improvement
The most obvious change in the last 20 years has been the increase in trees planted, with total tree population increasing from 3,8 million in 2005 to 21 million by 2025. Perhaps this rate of growth was too fast to enable all growers to ensure best management practices were implemented on farm, as production of 16 000 tons DIS in 2005 from about 2 million producing trees (6 years old plus in 2005) resulted in average yield of 2,5 tons DIS/ha (assume 312 trees per hectare), declining to 2,1 tons DIS/ha in 2025 from 12 million producing trees with total production of 82 000 tons DIS. On the positive side, improvement in Sound Kernel Recovery (SKR%) from 26% in 2005 to 33% in 2025 was probably a result of a combination of better pest management, increased planting of higher kernel recovery cultivars and an increasing proportion of the crop coming from KZN (where total kernel recoveries are five percentage points higher than in other areas across all cultivars).
The disappointing stagnation/decline in average yields has happened despite increasing expenditure by SAMAC on scientific research, many improvements in cultural practices on farms and wide scale adoption of new technology. Irrigation is one that stands out, with computerised low flow drip systems allowing precision irrigation and fertigation installed in many orchards since 2005. Yet even these sophisticated systems are not all producing the sustainable higher yields anticipated, in some cases resulting in over fertilising creating faster vegetative growth and inefficient tree canopies.
Very pleasing to note is that many leading growers have become more dedicated to preserving the environment.
Especially since Covid and the price decline which triggered cost saving measures, there has been less use of chemical herbicides. Some growers are allowing the grasses and other natural vegetation to grow between the macadamia tree rows and allowing a cover of mulch to remain within the tree rows. This improves biodiversity in the orchards and contributes to soil conservation by reducing runoff during heavy rains. Some growers also plant a mix of grass and legume cover crops between the rows to provide a haven for beneficial insects. Combined with intensive scouting for the main macadamia pests, the use of more biological remedies for pest management and reducing reliance on broad spectrum pesticides, these growers are really making environmental preservation top priority on their farms. It is indeed most fortunate that the present range of biological pest management products has become available to growers in the last decade, as very few of these products were available back in 2005.
More use of systemic pesticides as drenches (neonicotinoid) products has also reduced the need to spray highly toxic broad-spectrum pesticides all over the place, helping the natural predator populations in our orchards to proliferate and do at least some of the pest control on our behalf.
The other big change has been the increase in the number of older trees in the orchards, from about 800 000 trees aged 10 plus in 2005 to some 7 million by 2025. Many of these trees are overgrown with very dense canopies resulting in declining yields per hectare wherever appropriate pruning/canopy management has not been regularly implemented. These big old trees also provide conditions conducive for fungal and pest development, making pest and disease control increasingly more challenging. This is one of the biggest challenges for our macadamia industry going forward and perhaps we have a lot to learn from the deciduous fruit industry in working towards more precise canopy management strategies with smaller, more productive trees at higher plant densities to improve yield and pest/disease management efficiency.
