Higher densities trial

Research aim: To assess the impact of dwarfing rootstocks and planting density on the establishment of new almond varieties in a 2-dimensional tree shape/fruiting space and the distribution of fruiting sites.

The outcomes sought are rootstock/scion combinations better suited to the 2-dimensional fruiting space concept, and, perhaps more importantly, a clearer understanding of what tree growth habit (i.e. architecture) might be preferable.

A strategic aim of the industry is to move toward shake-and-catch harvesting, driven by the need to avoid some of the weather-related nut quality issues that have dogged the industry in the past. The shake-and-catch engineering solution will be much simpler if the fruiting space is 2-dimensional (i.e. a more-or-less a thin hedge) as compared to the 3-dimensional fruiting space currently used. The industry standard varieties and the newer varieties being made available to industry, were selected for their suitability for the current way orchards are planted (i.e. “H1”). The vigour and growth habit that made them suitable for H1 planting densities do not necessarily make them suitable for a production system geared toward shake-and-catch harvesting. These varieties differ marginally in their growth habit, and it is possible that one or more of these varieties will be more suited to a closer spaced hedged row production system than other varieties.

Dr Michael Treeby

Video: Dr Michael Treeby - Introduction to research looking at High density nut trees

Video transcript - Introduction to research looking at High density nut trees

The next planting is where we start pushing those trees in closer together and there we're looking for more root stocks that are better suited to producing trees that are smaller, more compact if you like, and then also looking at scions which are stemming from the current Australian Almond Improvement Breeding Program for their suitability for those kind of plantings. So that really is a bit of a look for the orchards that will be established probably 10 years from now. The trial after that is slightly more radical. That's where we've really pushing things closer together and we're trying to, we're looking at all sorts of fairly radical tree training ideas and that's a trial that is very much you know right out on the fringe, if you like. Remember that the orchard of the future may well be a two dimensional fruiting space. By that we mean probably more or less like a grape vine is at the moment. This really just height and length and at the moment almond orchards are more or less a three dimensional fruiting space. They've got height certainly but I've got width and length as well and add some depth if you if you like. So, we're moving away from that in order ultimately to shake and catch. The industry wants to move away from shake onto the ground, which is an uncontrolled space that potentially produces some results and some issues for them, to a situation where they shake and catch the fruit. So, it doesn't go onto the ground, it removes that problem. So we'll be looking at a row crop very much a row crop, but with the dimensions or the layout of the orchard, is the bit we don't know, and the light experiment if you like, trial, is trying to provide the design specifications in one of another term.

Video: Almond research 2019 - introduction and progress of orchard development for the high intensity plantings

Dr Michael Treeby and progress of the almond orchard with high intensity plantings

Dr Michael Treeby, Senior Research Scientist from Agriculture Victoria, introduces the research on intensifying almond orchards, with a look at the progress of the orchard in December 2019, at the Nut research orchard in Irymple, Victoria.

Transcript - Research into intensifying almond plantings with Dr Michael Treeby

This trial has been established to try and answer some questions around the intensification process for almond production. Most people's initial response to trying to intensify almond production is to just plant more trees together, closer together. And in a sense, we don't really know what's going to happen when we do that.

We know that they will probably fill out the space between the trees more or less sooner or later, depending on how many trees we have. We don't know what's going to happen as far as tree structure goes. So, in a sense, we don't know what sort of tree structure we need for that intensification or that more intensive production system.

What we've planted here is a fairly extensive trial, about six hectares. It's three or four rootstocks, which will impart varying degrees of vigour to different scions and the different scions are all the new University of Adelaide varieties that have been recently released and are being adopted by industry. They're all self-fertile as well.

They all have different tree structures. Some branch more, some weep, and we don't know what that might mean with the different rootstock underneath it, in terms of what sort of structure will be suitable in the future for intensive production systems. That's exactly what this whole thing is about.

Filling out the space, what happens to that tree structure has a function of that spacing and then of the rootstock underneath, which may well change the tree architecture in ways we don't quite know yet. So, the difference in vigour is obvious now and will become really obvious in those more intensively planted, those trees that are planted closer together. They will fill out the space quicker. We don't know whether that has a negative effect or not. We know that they will get pretty crowded, and probably start to look pretty ugly, but we don't know whether that really matters.  That’s more or less the guts of it.

The vigour will be affected by the rootstock and the scions to some degree, but mainly the rootstock, and as we plant them closer together, does that mean that they would just simply start going expanding outwards? We simply don't know. In some senses the treatments, the extreme treatments are extremes to try and prove the point, to push the point, and to accelerate the trial, if you like, the progress in the trial.

Project acknowledgement

This project (RnD4Profit-15-02-011 ‘Advanced production systems for temperate nut crops’) is supported by Horticulture Innovation Australia Limited, through funding from the Australian Government Department of Agriculture and Water Resources as part of its Rural R&D for Profit programme and Agriculture Victoria (Victorian Government), the South Australian Research and Development Institute (SARDI), the Almond Board of Australia (ABA), and New South Wales Department of Primary Industries.