Fruit production in the future

Robotic waiters

Robots serving food in Chinese restaurant.

Where will the raw materials come from to “manufacture” our future food? ‘Fruit growing in the future’ is a paper presented by Dr Mike Nichols at the 2017 Protected Cropping Australia Conference.

It is the winter of 2100 and in a restaurant in Auckland and the waiter asks a diner about his choice of dessert.  The reply is a fresh white-fleshed nectarine, so the waiter proceeds to the kitchen and dials up the request on the food computer, which promptly instructs the 3-D printer to produce the nectarine. 

Pie in the sky?

Did the Wright brothers envisage when they first flew their heavier-than-air plane at Kitty Hawke on December 17, 1903 that just over 100 years later the Airbus 380 would transport over 500 passengers at close to the speed of sound on flights with a range of 17 hours?

Did the UK Government when it established the “red flag law” in 1865 – which required all motor vehicles to be preceded by a man with red flag – consider that 150 years later there would be autonomous (self-drive) cars.

Algae production

Prototype algae production at University of Queensland.

I suspect not!

So where will the raw materials come from to ‘manufacture’ our future food?  The most likely source is algae, which is currently the most efficient converter of solar energy into chemical energy.  For example, at the University of Queensland there is a project underway to grow algae in water races in order to use the algae directly as a source of omega 3 rather than getting the omega 3 further down along the food chain from the oily fish.

In fact, developing food with 3-D printers is already a reality, with conferences on the subject being held this year in Venlo, Netherlands, and also in Melbourne, Australia.  Of course, in relation to fruit growing this development is some way down the track, and there are a number of steps to go before it becomes a reality.  However, in the long-term it is likely to spell the end to the southern hemisphere’s monopoly of providing the northern hemisphere with out-of-season fruit and vegetables.

However, in the meantime there are a number of other developments on the horizon, which will influence the way in which we produce fruit.

Management Bonus

Figure 1. Note how good management bonus is higher in a controlled environment, but good luck bonus is higher in the field.

In 1950, J. P. Hudson looked at the average yield from the best 10 per cent of growers and record yield of a number of crops.  He demonstrated that the best 10 per cent of growers consistently produced higher yields due to more capital and, more knowledge—what he termed a “good management bonus”, but that the record crop (almost certainly obtained by one of the better growers) was a “good luck bonus”, due to exceptional weather conditions.  He also demonstrated that the magnitude of the “good management bonus” was higher for greenhouse crops than for outdoor crops, but that the reverse applied for the “good luck bonus” (see Figures 1 and Figure 2). A similar pattern is likely to occur now, but with the greenhouse tomato yields some four times what they were 60 years ago, due primarily to improvements in the control of the greenhouse environment, and in our knowledge of crop requirements (see Figures 3 and Figure 4).

Controlled greenhouse environment comparison

Significant increase in productivity in controlled greenhouse environment when compared to the field from 1950-2010.

A key development is hydroponics – something, which barely existed in 1950.  Commercial hydroponics really only gained momentum in the 1970s, but now is the most common way of growing greenhouse crops in developed countries. Dr Lim Ho has demonstrated that the introduction of better environmental control (particularly the use of hydroponics) by commercial tomato growers in UK resulted in steadily increasing productivity gains, compared with soil-grown greenhouse crops.

Effect of hydroponics on productivity of greenhouse tomatoes in UK.

Effect of hydroponics (mainly) on productivity of greenhouse tomatoes in UK.

Protected cropping of fruit

In fact, this is already here. Certainly, an increasing area of berry fruit is being grown under high tunnels, and this is likely to increase in the future as the advantages of growing without the risk of rain damaging the crop become apparent.  The potential for higher yield of better quality fruit, and the ability to harvest over a longer season, in any conditions are very clear.


Strawberries in high tunnels in the soil.

Protected cropping (and by this meaning complete rain exclusion, not the netting covering currently being used in many kiwifruit orchards), is slowly incorporating hydroponics in the berry fruit industry although surprisingly, in the USA there seems to be a tendency to stay with soil-grown crops, in spite of the clear advantages of hydroponics, with its enhanced water and fertiliser efficiency.

Hydroponic strawberries

Hydroponic greenhouse strawberries on table tops.

The only tree fruit crops, which are currently being grown under protected cultivation to any extent, are sweet cherries, and this has only become possible due to the development of dwarfing root stocks (such as Gisella), and the need to protect the ripening crop from rain to prevent splitting.  The cherry industry has yet to consider the potential of hydroponics.  A few other fruits have been grown under protected cropping systems, in particular the rain sensitive stone fruit such as nectarines, peaches and apricots.  Figs produce extremely well under high tunnels, particularly when combined with hydroponics.  The ability to fully net the cropping area against birds is relatively straightforward, as the structure (supporting the plastic film), is already in place, and the net can be simply put over the top of the plastic.  This (of course) applies to all the fruit crops, particularly the ripening berry fruit, which are very attractive to birds.

Growing under protected covers offers the potential to extend the harvest season both earlier and later, and also the range of crops, which can be grown in your area.  It is a good question (particularly in relation to biosecurity concerns) as to why we should need to import products, which we can grow efficiently in New Zealand.  I refer specifically to dessert grapes, but other crops such as melons, seedless watermelons etc. also come to mind.

On the question of wine grapes, it is considered by the experts (of which I am not one), that it is only possible to produce a top-class wine from top-class grapes.  New Zealand (because of scale) will never be able to compete with the mass world wine market, so perhaps should aim primarily for the top of the range.  With our uncertain climate, (this a is a good example) and with the risk of even greater uncertainly in the future due to global warming, the potential for growing a rain protected (and also bird proof) wine grape crop looks attractive.  Linking this with hydroponics should provide the potential to grow top quality wine grapes anywhere in New Zealand, on any soil type.  The need to invest huge amounts of money on purchasing land on the Gimblett gravels or at Martinborough no longer becomes necessary.  After all, both sites are essentially growing almost hydroponically.

Of course, moving orchard trees permanently into greenhouses will require changes in the way in which they are grown. In this respect the work of Dr Stuart Tustin (of Plant and Food Research near Havelock North) is showing a possible way in which not only crop production can be enhanced, but also management methods changed.

Dr Tustin has proposed for apples that far higher yield of fruit might be achieved by a bi-axis candelabra training system.  In this design, the rows would be about 2m apart, but the trees 6m apart in the rows, and the trees trained almost in two rather than three dimensions.  This is similar to the system being developed for cherry trees, and peaches and nectarines would be even more suitable for this type of training.

Protected cropping might well have potential advantages for organic fruit production, as the absence of rain on the crop could have a major influence on the need for fungal and bacterial disease sprays, and might potentially enhance the efficiency of biological control.  Hydroponics would not be an option, however, under current organic regulations, although this is currently being questioned in the USA.  Certainly, in our unsprayed greenhouse strawberry studies we have had close to zero fruit rots, and (when the predators were introduced at the appropriate time) excellent control of thrips, spider mite and cyclamen mite.

Read the full paper in PH&G October 2017 / Issue 184.  Ω