Futuristic tree designed
He heads a research team looking at new tree growing systems funded by an MBIE (Ministry of Business, Innovation & Employment) Science and Innovation programme, Future Orchard Planting Systems, which takes the idea of tree structures back to first principles in an attempt to makes gains in yield.
Stuart says currently the best orchards in New Zealand yield around 100 tonnes per hectare using just over half of the available light. Using vastly different growing systems which intercept 90% of the available light could yield a theoretical 169 tonnes per hectare.
The apple “super orchard” to capture this much light will have a planar two-dimensional system with trees planted close together.
Stuart says the first prototype has 3 metres between trees, and 1.5 or 2 metres between the rows. There will be a tree density of 1,667 to 2,222 trees per hectare, with 16,670 to 22,220 vertical stems per hectare. The vertical stems would be just 30 centimetres apart in the row, with vertical fruiting stems up to 3.5 metres high with no branching.
“We don't care if conventional machines won't work, this would be at the forefront of a whole new production system requiring new machinery.” The bi-axis system produces 30% more dry weight of fruit. Prototype orchards are being planted in Hawke's Bay and Nelson with various apple varieties, and the new Prevar crunchy pear variety Piqa Boo.
Research is also being conducted into ways to make existing blocks highly productive. Royal Gala on M9 can be improved from 100 tonnes per hectare to 130 tonnes per hectare using new techniques such as Artificial Spur Extinction. This is a new management technique that reduces the number of flower buds in the tree canopy. The process copies natural bud abortion that occurs in apple trees.
Other research is also being carried out into dry matter content in fruit, to promote better tasting fruit. The research project A Juicy Future is working on tastier fruit profiles, and the relation of sugar to acid and volatiles.
Remodelling the basic shape of an apple tree to intercept more light could lead to vast gains in yield, Dr Stuart Tustin, lead scientist at Plant & Food Research, believes. “This would be at the forefront of a whole new production system requiring new machinery.”