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Summary of full report
Taro Production – mechanisation and industry development
by Craig D Lemin
July 2006
RIRDC Publication No 06/019 RIRDC Project No DAQ-291A
antiquorum) is also given–particularly in the areas of harvesting and washing.
Principally, the technology practiced or previously used by growers in Australia is reported.
References to technology used/trialled overseas are noted where appropriate. Also, machinery development initiatives conducted within or using funds from the project are reported: a mechanical corm planter; a single row mechanical digger and a continuous throughput mechanical washer.
The report also tries to identify the impediments to adoption of mechanisation under Australian production systems and existing technology gaps. By way of introduction and background information, the cost structures of existing production systems are broadly discussed. Likely savings from effective adoption of mechanisation are outlined. Opportunities these create for expansion of existing markets or entry to new (export) markets are discussed.
Who is the report targeted
at?
The project was developed
in consultation with Taro Growers Australia Inc. and conducted in collaboration
with individual growers. Therefore the report is principally for the benefit
of taro growers or people considering entering the industry. The report
should also serve as a reference for researchers conducting or developing
research and development projects in taro. Finally, the report makes recommendations
in relation to mechanisation of taro production which should be considered
by growers, industry representative bodies, researchers and fund provider/investors
alike in developing or assessing projects. Such projects need not necessarily
be focussed on mechanisation in particular but should consider the recommendations
because of the potential strong interrelationships between the production
system and mechanisation.
Background
Taro is an old and important
world crop–it is widely cultivated as a subsistence crop but also commercially.
Generally however no significant mechanisation is practiced outside of
countries like USA (Florida, Hawaii), Japan and Australia.
Production in Australia is mainly in Queensland coastal areas, north coast NSW and around Darwin in the Northern Territory. Estimated annual production in Australia is around 1000 tonnes with a wholesale value of about $3.5 million. Significant market opportunities exist based on expansion of the domestic market (volume and through import replacement) as well as selling into export markets.
In addition to product promotion, this will principally rely on improving production efficiency through mechanisation.
The industry is characterised by relatively small individual production areas which are intensively cultivated. Also growers enter the industry in response to low entry costs and periods of lucrative prices, but often exit when prices fall. Significantly a core of long term growers has emerged who produce relatively consistent volumes and quality.
Australian growing systems are based on a diversity of planting material and layouts. Irrigation is always used–typically drip tube or overhead sprinklers. Effective weed management is important and often an issue. Harvesting and to a lesser extent planting have typically been performed manually.
Manual washing of corms is also laborious, influenced by the condition of corms at harvest time.
Although mechanisation is practiced by a few growers and in all aspects of the production system there has been no widespread or consistent adoption of mechanisation in the industry. This is due to a range of factors broadly categorised by:
Aims and objectives
This project was based on
lowering production costs of Australian-grown taro through mechanising
aspects of the production system. This would increase the competitiveness
of product in domestic markets and the profitability of existing producers.
In the longer-term, an expanded and more stable industry would have the
potential to supply export markets by virtue of a lower cost-base.
The project aimed to bring about greater adoption of mechanisation in the industry by raising awareness amongst producers and undertaking technology development in an attempt to solve particular issues.
The three working principles
employed in the project were:
Methods used
The project was conducted
principally in co-operation with growers. Industry practices and experiences
relating to mechanisation were documented based on visits and discussions
with growers. In association with this, a secondary undertaking was to
note relevant references to taro mechanisation from overseas sources/literature.
Using an action-learning approach, harvesting and planting equipment was developed and trialled in co-operation with growers. Also, independent work to design, develop and test a technique for mechanised washing/cleaning of taro was undertaken.
Results and key findings
Mechanisation of taro
planting
With commencement of the
project it became apparent that many growers were successfully using mechanical
planters for planting taro as ‘setts’ (sections of corm and leaf stalk)
and corm pieces.
Typically the equipment was based on second-hand potato, vegetable or tobacco planters or had been developed by the growers themselves. Significant labour savings were achievable in comparison to manual planting.
In the project, a second-hand potato planter was sought for modification and trialling in taro.
However a suitable machine could not be located. Instead funds were made available to construct and successfully test a simple tool-bar based planter for planting corms in a double-row configuration.
This machine was developed in collaboration with a grower and engineering workshop at Babinda in north Queensland.
Mechanisation of taro
digging (harvesting)
Large-corm taro grown in
Australia is almost exclusively manually harvested with only limited adoption
of mechanised diggers. Those diggers which are or have been used by growers
are typically based on simple, second-hand (and usually run-down) potato
diggers in single or double row configurations. These machines are unsophisticated
and do not offer major advantages from their use–uptake has therefore been
limited.
One large scale taro grower in south-east Queensland successfully and exclusively employs more sophisticated mechanical harvesting machinery based on an evolution of equipment developed on farm. These include a tractor-drawn double row digger with collection of harvested corms in a chaser vehicle and a self-propelled harvester also with on-board collection of product and delivery to chaser vehicle. This machinery has been developed at considerable expense and effort. However it has some limitations relating to wet field performance, weed and vegetative matter separation and power requirements.
In the project, a second-hand potato/sweet potato digger was sought for modification and trialling in taro. However a suitable machine could not be located. Instead funds were made available to modify and test a simple digger which was purchased by some local growers. After a step-by-step development process the machine was developed to the point where it was successfully used to dig taro but requires further development to optimise its performance. Details of the development process and proposed modifications are reported.
Overseas references to mechanical taro harvesting technology are discussed. The design and potential to use more sophisticated and state-of-the art potato harvesters in taro is also discussed.
Some investigation of harvesting techniques appropriate for small-corm taro was also undertaken. A potato seed bed conditioning machine trialled in northern NSW appears to offer good potential for harvesting this crop and segregating the small corms (which have a dense clumping habit) at the same time. Also, information obtained on a Japanese developed ‘Universal Tuber Harvester’ suggests the machine would be very effective with this crop. It employs a similar mechanism for segregating corms as the soil conditioner seen in northern NSW.
Mechanisation of taro washing Cleaning and washing of taro is a laborious task made more difficult depending on growth and field conditions at the time of harvest. Generally, market and grower preference is for corms to be completely free of any soil, rootlets and side shoots/cormlets removed, petiole trimmed neatly and skin with a natural appearance (not over-cleaned/abraded). Achieving this in the context of a continuous mechanical washing system is a significant challenge.
A single-corm mechanical washer designed specifically for taro by a north Queensland based grower in conjunction with an engineering workshop is described. Also, a rather unwieldy but nonetheless effective washing plant installed at a large taro/ginger growing operation in south-east Queensland is described. Other and less successful attempts to design mechanical taro washer are also noted.
Finally a machine recently developed by a grower in north Queensland has been praised by growers who have seen it in operation for its effectiveness and simplicity (although this machine will not remove roots). Although viewed, this machine is not described in deference to preserving the intellectual property of the developer who intends to commercialise the machine.
In the project, significant effort was dedicated to design, construction and testing of a machine to continuously wash taro corms using a novel technique. The machine is described and its performance evaluated. Further development of this machine is required to improve its operation/performance but it offers significant potential with relatively modest modification. With the benefit of experience from development and testing this machine an alternative design based on the same technique is also proposed.
Other equipment–particularly onion topper-tailers, also appear to offer significant potential with taro for root removal. A simple topper-tailer machine previously used with taro is described.
A brief description of equipment used with relative success for washing small-corm taro is given.
This equipment was imported from Japan and installed in a relatively small-scale washing/packing facility on a farm in northern NSW.
Implications for stakeholders
Planting
Mechanisation of taro planting
is increasingly being practised by growers using either setts or corm material.
There appears rather less impediments to its continued uptake in industry
compared to mechanical harvesting for instance. Those factors which are
of some significance would include field trafficability at time of planting,
equipment availability and labour availability (assuming operators are
required besides the grower/manager). Whilst mechanical planting will have
implications for other mechanisation practices in the growing system–it
does not of itself rigidly impose necessary changes to the subsequent growing
and management of the crop.
Linked with the adoption of technology for mechanical planting is a decision on the type of planting material, layout and bed system. Choice and design of planting technology should be based on an understanding of the relative importance and economic consequences of such factors–not on the technology that may be available.
Harvesting
A number of factors have
inhibited adoption of mechanical harvesting of large-corm taro and most
are still evident. Most are related to the relative immaturity and small
scale of the industry as well as technical difficulty and equipment availability.
While the technical feasibility of mechanically harvesting taro has been demonstrated by existing growers and in the project, there is not currently a technology that will suit all growers under all conditions. Greater industry scale and standardisation of the production system are required to fully capture the benefits of mechanical taro harvesting and drive adoption. This can be achieved through contract or pooled harvesting arrangements and a ‘bottom-up’ approach to re-engineering the production system in the context of mechanical harvesting.
Notwithstanding this, mechanical harvesting on the Wet Tropical Coast of Queensland will always be difficult for crops that are harvested during the wettest part of the year. Growing in drier climates would greatly enhance mechanisation potential.
Mechanical harvesting of small-corm taro is technically possible and in the event of significant production volumes would have a high likelihood/priority for adoption. This is because viable production of this product in Australia is more or less reliant on mechanised harvesting systems.
However, any such technology should incorporate an effective technique for breaking-up and segregating the corm mass/clump on-board the harvester. A potential technique is identified and appears similar to the method employed on a well developed, Japanese designed corm harvester.
Washing and cleaning None of the equipment/technology either used in industry or developed in the project for washing and cleaning large-corm taro is completely satisfactory. Unfortunately at the typical individual farm scale, a single machine for washing and cleaning taro that is relatively low cost and fully automated is probably not possible. However, such a machine/system is conceivable at the scale of large farms or co-operative style packing sheds. Such a system is proposed based on further development of existing equipment/methods and trialling/development of some new equipment. Such a system is propositioned on removal of most vegetative material (tops and weeds) in the field; manual trimming to remove daughter corms and relative uniformity in size and shape of corms through material selection, management practices and/or grading.
Mechanisation of washing and cleaning of small-corm taro is seen as feasible provided that mechanical harvesting of this product incorporates an effective means to segregate corms on the harvester and separate the majority of extraneous matter. The plant could be based on technology for washing potatoes or existing Japanese technology for handling this product. Application of computer vision techniques for sorting and automatic shaker packing should be possible in large scale operations.
Recommendations
Large-corm taro
No work on development of
planters is recommended besides that aimed at improving the performance
of existing equipment where clear benefits are proposed. However, growers
may need more information to make the appropriate choice on the type of
planting material they should be using in their production system (corms,
setts or plantlets). This may require agronomic studies and/or review of
literature and grower experiences coupled with economic analyses.
Trialling of current potato harvester technology in taro is recommended with capacity for modification and adaptation of the machinery as required. This may require setting up dedicated test blocks and purchase or hire of a suitable machine. Otherwise, researchers and growers undertaking trips overseas should try to examine harvester technology potentially in use and should be supported in this. Particular locations for such technology include Hawaii, Florida and Japan. The existing digger developed in the project should be made available for use and potential further development by grower members of TGA.
Furthermore, agronomic studies aimed at investigating an optimum or ‘standardised’ production system to enable mechanical harvesting should be supported–particularly if this helps open up potential export markets for product.
Further development of washing technology for taro is required. Development projects that should be considered/ supported include:
From an overall perspective
factors that will assist faster and wider adoption of mechanisation in
taro include:
Small-corm taro
A program for development
of harvester technology for small-corm taro should only be considered in
the event of renewed prospects for selling into export markets. Initially
such a program should assess the design and performance of the Japanese
manufactured ‘Universal Tuber Harvester’. Any technology implemented (by
design or importation) should incorporate a mechanism to segregate harvested
material into individual corms.
Similarly work on washing and cleaning of this product should only be considered in the context of a proposal for a centralised washing/packing facility. It is likely that such a facility could be based on existing technology for washing mainstream vegetable crops. However, further investigation or development of equipment for root removal may also be required based on either existing Japanese root cutting machinery or onion topper-tailers.
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