Wednesday, 21 May 2014

Tunnel vision - protecting tomatoes in the Pacific

ACIAR research on tunnel greenhouses offers smallholder farmers in Fiji and Samoa opportunities to grow produce and supply markets, come rain, hail or shine. Our Pacific Crops research program manager, Dr Richard Markham,explains how...

The trouble with growing tomatoes in most Pacific islands – at least the ‘high islands’, with mountains down the middle –  is that it’s too wet on one side (facing the trade winds) and too dry on the other (in the ‘rain shadow’ of the mountains). Protected cropping, using a greenhouse in combination with irrigation, can in principle offer a neat solution for smallholder farmers, protecting their tomatoes and other high-value vegetables from the extremes of climate, and allowing  production all year round. The challenge in practice is to get the right balance between cost and quality for the greenhouse structure, while managing heat and moisture, pests and diseases in the crop, and the demands of the marketplace.
Edwin Tamasese (far right) and Elio Jovicich (centre right) discuss
the pros and cons of greenhouse structures currently available in
Samoa with Queensland researchers

Finding solutions
Two ACIAR projects are helping farmers in Fiji and Samoa to tackle these interlocking problems. First, the structures themselves: a project (see 1 below) is working with an importer in Fiji, Mr Wah Sing Yee, to source models from China that are cheap enough for growers to afford but strong enough to stand up to normal tropical storms.

As a former vegetable producer himself, Mr Yee understands what the growers need and can negotiate the exact specifications with the manufacturers. For example, one useful feature is a design that enables the farmer to strip off the polythene roof and netting walls in the event of a cyclone, sacrificing the crop but saving the structure for re-use. 

Dealing with heat
The next problem to deal with is excessive heat. The cheapest plastic tunnels are only 2 to 3 metres high and hot air accumulates under the roof. Low-growing plants like lettuces will usually do quite well in this environment. But taller, more valuable crops like tomato, cucumber and capsicum will only grow for a metre or so and then get too hot to set fertile seed and produce fruit.

Pests such as broad mites can seriously
affect plant growth (as with this tomato)
The project’s innovative greenhouses (see photo below) are much taller and have a netting-covered vent at the ridge. “This design keeps rain and insects out but lets the heat escape”, explains the project’s lead researcher, Elio Jovicich. Crops can be grown on trellises or wires right up to the roof, letting them grow and fruit over a long season. The new tunnels cost three times as much as the lower, unvented ones – but they should offer much higher returns, if properly managed.

Fighting pests and diseases
Then there are pests to cope with. The greenhouse’s plastic roof keeps out the excessive rain that promotes fungal and bacterial diseases. Our greenhouses with netting walls ensure good ventilation, again reducing the risk of disease and keeping out some insect pests. However, if pests do get in, they can run riot in the warm, dry conditions of the tunnel and destroy the crop.

Entomologists and pathologists from another ACIAR project are working with the team to figure out how to cope with pests such as broad mites that are unfamiliar to farmers in the Pacific. Elio says: “These are the same pests that we have to deal with in Queensland – so this research helps Australian growers as well as those in the Pacific islands”.

The project's new, improved structures have strong footings
and metal frames - essential for surviving tropical storms
Skills for market
Farmers investing money and time in new technology and more-intensive crop management will need to get a better price for their crop, if all this effort is to be worthwhile. Other ACIAR research (see 2 below) is helping smallholder farmers in Fiji and Solomon Islands to understand what demanding markets such as tourist hotels require, and to equip them with the skills they’ll need to supply them.

These include technical skills in production and post-harvest handling, and business skills in investment planning and negotiating with hotel buyers and traders. So far, this project is working only with farmers producing field-grown tomatoes, but the business skills will be all the more important as farmers start to make the larger and riskier investment in protective structures and more-demanding crops. 

The final product - polythene and shade cloth keep out the rain
and moderate the sun's heat, and netting on the side walls and
roof-vent help exclude insects, while maximising ventilation
New options, new opportunities
Bringing in these various options is beginning to segment the market and offer farmers a business development pathway to follow. Less skilled or more cautious farmers may begin by producing less-demanding crops, like lettuce and Chinese cabbage, using the most basic technology. As they gain skills and confidence, they can graduate to larger structures, more complex production techniques and higher value crops – which then offer better returns on investment.

“Perhaps this will help to bring a new generation of young people back into horticulture”, reflects Edwin Tamasese, a leading horticulturist and vegetable supplier in Samoa. “There is less drudgery, more technology and more of an intellectual challenge in this kind of agribusiness – and more attractive profits.”

If Edwin and the project teams are right, these innovations could transform the prospects for horticulture and smallholders in the Pacific islands. 

By Dr Richard Markham, ACIAR's Pacific Crops research program manager

More information:
This research is part of the Pacific Agribusiness Research for Development Initiative (PARDI), led by the University of Queensland.

PARDI's website hosted by the Secretariat of the Pacific Community
ACIAR's PARDI website

1. PARDI project PRA 2012.01 Developing protective production systems for vegetable growers in Fiji and Samoa
2. PARDI project PRA 2011.003 Developing an integrated participatory guarantee system in the Pacific Islands in support of sustainable production of high-value vegetable crops

Supporting ACIAR project PC/2010/090 Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production

1 comment:

  1. This is very useful information for farmers who would like to do tunnel farming. Where can I get the design specs and details on these new tunnel design?


Thanks for taking the time to comment!

Note: only a member of this blog may post a comment.