Pedestrian orchards better for workers and growers
Industry Best PracticeAustralia is, if not already, very close to being the highest price orchard labour market in the world. Availability of labour seems acceptable at present but many growers are starting to find availability of skilled labour an increasing constraint to future business confidence.
Pickers will be more likely to want to work in a pedestrian orchard system, which is an advantage during times of labour shortage.
APAL has focused on productivity and mechanisation to improve labour efficiency and hence profitability of Australian orchard businesses. These strategies, although very effective, are capital intensive and increase fixed capital costs. The industry needs to challenge this paradigm with alternative strategies to ensure Australia’s orchards are globally competitive in the future.
Pedestrian orchards are, by definition, orchard systems where all work is completed from the ground eliminating the need for ladders.
Expected benefits of pedestrian orchards are:
- Cost savings for the orchardist through more efficient labour use.
- Lower picking, thinning and pruning costs.
- Reduction in occupational health and safety (OH&S) risk.
- Pickers will be more likely to want to work in a pedestrian orchard system, which is an advantage during times of labour shortage.
- With smaller trees, canopy development may be faster.
Pedestrian orchards have been tried in the past in Australia in an effort to improve labour OH&S and efficiency. The problem with the earlier attempts was that they were done on conventional wider row spacings. All this ended up doing was restricting the light interception leading to poor yield and consequently, not only was income down, but the cost of labour per kilogram of fruit produced was also no better.
Now, with more technology at our disposal, the question is being asked: Is it possible to have pedestrian orchards without needing to limit yield?
The cost of height
Current intensive orchard system plantings described as ‘tall spindle orchards’ are typically planted at 2,000 to 3,000 trees per hectare and have a tree height of 3 to 3.5 metres. Thinning, pruning and harvest tasks need to be completed off the ground often with ladders and, more increasingly, platforms.
If we assume during pruning and thinning, the top of the tree is visited twice and during harvest, twice more, that is four times up a ladder in a season. To reach the top of the tree is usually a climb of about 1.2 to 1.5 meters. Now let us assume a moderate tree density of 2,200 trees per hectare, that equates to 10,500 meters of climbing per hectare per season. Four times up, multiplied by 1.2 metres climbed, multiplied by 2,200 trees per hectare, equals 10,500 metres climbed. Wow, 10,500 metres climbing per hectare in a season.
Sea level to the top of Mt Everest is only 8,848 metres, yes really. As well as being a physical task it’s also time consuming, nothing else being done just climbing up and down again. I have checked these calculations many times even looking at the number of times a ladder is climbed during harvest. The number still comes out at 5,000 to 6,000 metres climbed for harvest, something similar for pruning and thinning combined.
With this 10 kilometres of climbing in mind it is easy to initially justify platforms, effectively eliminating the climbing ladders for all or some of the tasks. The first problem is that many growers do not have enough blocks of platform-friendly orchards to justify the investment and the capital cost is too high to justify investing in the equipment to service just a small area. The second is that during periods of fluctuating crops (e.g., frost, hail, heat, etc.) increasing fixed capital is hard to justify and afford. Thirdly, platforms are not always suitable for all orchard terrain.
The option of eliminating ladders from orchards then becomes a possible solution by reducing the height of trees and having a pedestrian orchard. There has been an increasing interest in pedestrian orchards where all manual tasks are completed from the ground without ladders and without platforms.
When considering pedestrian orchards, it seems obvious that the tree height needs to be reduced and rootstock/scion combinations need to be reconsidered. Vigour management of mature canopies of smaller trees will be an important tool. Subtle changes such as twin stem trees is one way to manage vigour and achieve a calm tree in a smaller space.
Balancing tree height, row spacing and yield
The real criticism of a pedestrian orchards is that reducing tree height will mean a reduction in yield and resulting profit. With vertical orchard systems, row spacing will have to come closer to try and maintain light interception, but row width will always be limited by machinery access. The closest row spacing with current equipment and bins is probably a 2.5 metre row spacing. A number of pedestrian orchards are being established in Washington State, USA, with a shortened four to five wire ‘V’ structure making it easy to maintain canopy volume and machinery access, the current target for these orchards is still 80 to 100 tonnes per hectare.
The effect of an orchard system’s yield profile on the success of an investment is in part due to both the ability to produce early and achieve high mature yields. The balance between these two components of yield will drive the investment outcome. Pedestrian orchards by their definition have smaller trees and are likely to reach full canopy development earlier than other orchard systems with larger trees. The point here is that lower yields may not be the reason to dismiss pedestrian orchards because early yields may outweigh lower mature yields. Confirming accumulated yield profiles and running comparative models will help growers make informed decisions about whether to establish pedestrian orchards.
To combat potential lower mature yields and reduced profit, initial overseas studies have shown a 30 to 40 percent savings in labour when all work can be completed from the ground. With labour costs around $0.40 per kg a 30 per cent saving would be around $0.12 per kg or close to $5,000 to $6,000 per hectare.
There are continuing comments from growers not having ladders in their orchard, that labour is easier to attract, out competing orchards planted in an older style.
Measure your way to success
In evaluating pedestrian orchards there is a need to continue investigating and quantifying the four key indicators of success of a pedestrian orchard:
- Speed into full production.
- Labour saving achieved by task.
- Full production achieved.
- Capital to achieve this.
These indicators then need to be compared against conventional orchard systems to help determine if this orchard system is the more viable option.
Pedestrian orchard trial – Tasmania
As part of the Future Orchards’ Focus Orchard program in Tasmania, the Community Orchard Group wanted to create a case study on pedestrian orchards. Initially the group wanted information on establishing a pedestrian orchard and identified the Focus Orchard block on GC Miller and Sons’ orchard in Hillwood in northern Tasmania as a trial site.
Twin leader trees are a way to lower establishment costs and improve vigour control in mature trees. A disadvantage of twin stem trees that can occur is unevenness of each leader, decreasing the consistency of canopy development and crop distribution. Delayed heading was suggested as a technique to achieve more even leader development. A trial was set up on the Focus Orchard to compare the evenness and overall growth of a twin leader development between heading at planting and delay heading later in spring.
Leader growth
Leader growth was consistently greater in the headed treatment compared to the delayed headed treatment. There was a 16cm difference in leader length between the headed and delayed headed treatments on 21 December 2016, a 17cm difference on 1 February 2016, and an 8cm difference on 12 May 2016. There was only a slight difference in the average leader length between headed and delayed headed on 1 February 16 which was 8.3cm and 10.4cm respectively. There was little difference in evenness of leader growth between treatments at the end of the season (12 May 2016) with a 14.6cm versus 14.3cm average difference. The range of difference between leaders was greater in the delayed headed treatment.
Leader evenness
Leader evenness was first measured on 1 February 2016 after de-shooting (by selecting the two most even leaders) and again on 12 May 2016 at the end of season. There was only a slight difference in the average leader length between headed and delayed headed on 1 February 16 which was 8.3cm and 10.4cm respectively. There was little difference in evenness of leader growth between treatments at the end of the season (12 May 2016) with a 14.6cm versus 14.3cm average difference. The range of difference between leaders was greater in the delayed headed treatment.
Implications
Delayed heading did not result in more even growth between the two leaders and resulted in lost growth over the season. Based on these results delayed heading of new apple plantings would not be recommended as a practice to increase leader evenness in multi leader apple trees.
The trees were planted late (October) due to a very wet winter and results may have been different if planted and headed mid-winter rather than spring.
Acknowledgement
Future Orchards is funded by Horticulture Innovation Australia Ltd using the research and development apple and pear levy and funds from the Australian Government. It is delivered by AgFirst and APAL. Thanks also to Justin Miller (GC Miller and Sons), Tasmanian Focus Orchard, and Front Line Advisor Sophie Folder, Pear Consulting.
