While new varieties have certainly spiced up the apple industry, research discussed at the "Game of Fruit: The Survival Guide" symposium in the Western Cape earlier this month show the driving factors of profitability have been increased yields and lower exchange rates. But what will keep apple growers in business for the decade ahead? At Fresh Fruit Portal we speak with Hortgro Science general manager Hugh Campbell about the trends in irrigation optimization, shade netting and rootstocks that will further shape the sector. 

Many of the challenges facing South Africa's apple growers are not exactly unique - water scarcity, a need for greater efficiency and improving export-grade packouts - but combined with the country's particular growing conditions and history they do present a unique situation. 

Campbell says overseas visitors to Western Cape orchards are often surprised at the large size of the apple trees and usually suggest a greater use of dwarfing rootstocks that allow for easier orchard control.

"That's until they see the tonnages that we’re producing consistently," he says. 

"Our tons per hectare have increased - obviously the right variety you plant is key - but the most determining factor has been quantity. 

"We’ve seen a fairly substantive increase in yields, and also what’s interesting in the process is that there has been an increasing gap between the top 25% and the average."

As the efficient get more efficient, he says the highest-yielding quarter of growers is getting between 80-100 metric tons (MT) per hectare on average, while yields of 120MT are also not uncommon.

"If you look at Golden Delicious over the past eight years in terms of the top 25%, the average has gone from 72MT per hectare in 2010 to 99MT in 2017," he says.

On average though, the South African apple industry is achieving about 60MT per hectare. 

"If you compare South African producers and orchards with other parts of the world, we generally use more vigorous rootstocks.

"We generally have an  M793 vigorous rootstock, which is a bigger tree and has quite a lot more management required to keep it going and keep it in shape versus an M9 rootstock, which is used as an industry standard around the world mostly."

Addressing high sunburn rates

But all of that extra tonnage does not always translate to exportable fruit. Campbell says sunburn is the "biggest cull factor" in South Africa's apple industry, and that's why some in the sector are shifting toward production models that are better suited to protecting crops from the sun's UV rays.

"You can get 30-40% cull on sunburn in a bad year, it can go higher sometimes," he says. 

In Campbell's view, the biggest opportunity to reduce these damages is through the use of shade netting - a practices that is not very widespread to date.

"It’s low at this stage. You'll see it's less than 5% but you’re getting growers starting to plant something like Granny Smith under a shade net to mitigate against sunburn.

"I wouldn’t say it’ll be exponential but there will be quite substantive growth in the use of nets, and we’re seeing it across fruit types - in peaches, nectarines, apples, not so much in pears; on citrus they’re certainly looking at it, and on table grapes they’re looking at it too."

He says the downside of the practice is the management in fruit color, which has already been an issue in unnetted orchards this year.

"It’s a little bit more difficult to achieve the necessary color. If you look at something like Cripps Pink or Pink Lady getting the higher packouts of color, this year we had a very low color year - poor color - because of warm weather and not getting the cold nights in the pre-harvest period," he says.

The fruit coloring problem from netting is a dilemma that is yet to be solved, but one of the most noticeable differences is that in order to be practical, netting tends to go hand-in-hand with newer, dwarfing rootstocks.

"If you put a net over it you get much more vigorous growth, so a lot more management is required with more aggressive rootstocks. So certainly that's not as conducive to creating that kind of an environment with the netting," Campbell says.

"If we look at the newer, younger orchards they're going to more dwarfing rootstocks, more intensive systems."

Good science to back up strategy, arguments

He says the industry is about to embark on a project to measure the differences in productivity between netted and unnetted orchards. The idea is that with quantified differences a more convincing case for the practice can be made.

"There are also benefits in terms of water saving; we could be talking about potentially between a 20-30% saving in water usage which is a key driver," he says.

This relates to another of what Campbell identifies as the apple sector's key objectives ahead by "making every drop count" and fostering high-producing orchards.

"One of the big issues is the availability and quality of water, and certainly coming out of a fairly severe drought that speaks to the availability and optimization of water," he says.

"That’s one of our key drivers and key risk areas in a South African context and in a broader context. It’s a challenge that perennial crops sit with."

He says with a growing population that is increasingly in urban areas in the Western Cape, there is a great deal of competition for water and groups like Hortgro need to work hard to ensure enough water is dedicated to agriculture.

"We’ve got a project we’re currently looking at now about the amount of water that is required from a high-producing orchard," he says.

"In terms of water allocation you can justify why you should be allocating a high amount of water per hectare rather than a low amount, so it’s about providing good scientific evidence to demonstrate that an increase in water increases the productivity up to a threshold. 

"You’re trying to optimize each drop rather than having a blanket allocation per hectare which is the general trend of the way things go – 5,000-6,000 cubic liters per hectare, whereas in actual fact in your high-producing orchards you’re requiring to be highly productive and to deliver the fruit size and the crop in the order of 10,000-11,000 cubic liters per hectare."

He argues it would be better to have fewer hectares but with each having high yields, than to have more land producing less fruit per hectare.

"We're also looking at over-irrigation versus under-irrigation. The efficiency of irrigation is and has always been a major issue but in times of drought it becomes more of an issue," he says.

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