Post-harvest handling very important, growers told

Press, 6 May 1983, Page 18

Post-harvest handling very important, growers told

One of the most important topics facing New Zealand’s horticultural industry is the development of successful post-harvest handling systems for fruit and vegetables, was the message given to horticulturists and other interested people in Christchurch last week.

Post-harvest handling was the title of one of four seminars held in conjunction with the South Island Horticultural Trade Fair.

Speakers emphasised the need for New Zealand to export produce of top quality only and outlined the necessity for careful handling of fruit and vegetables after harvesting to ensure they arrived in the marketplace in excellent condition.

Professor Richard Rowe, Professor in Horticulture at Lincoln College, said the post-harvest handling of fruit and vegetables was the achilles heel of horticultural development in New Zealand.

The technology used in the production of horticultural crops was very good, but New Zealand had fallen behind in the development of post-harvest handling said Professor Rowe. Increases in horticultural production could not be consumed on the local market, so future production had to be destined for export, which required top quality produce. European and North American consumers had a vision of New Zealand being underpopulated, fresh and unpolluted and that it produced clean, crisp crops. It was up to New Zealand to capitalise on this image by delivering produce in a fresh condition and of top quality. Vegetables and fruit which arrived at their destination in a poor condition would immediately destroy this advantage. Except for crops such as onions and apples, exporting relied heavily on airfreight, but this had two limitations — the cost, and the availability of aircraft to carry the required quantities and type of produce. These restrictions meant that many products would have to travel by ship.

Mr Ross Lili, a scientist at the M.A.F. Horticultural Research Centre at Levin, said there was now an increased awareness of the advantages to be gained from improved posthandling methods of horticultural crops.

This had been stimulated partly by the move to market fresh produce overseas where long distance transport and demanding markets made it essential that the very best postharvest handling procedures were used.

The crops should be harvested at the optimum stage of maturity, depending on the storage required for transport and marketing. For most crops this is the stage when they are sufficiently mature to ripen normally after harvest, but before softening has fully advanced.

Uniformity of maturity was important if the crop was to be of top quality, and harvest damage should be avoided. Produce should be graded to ensure uniformity both within a consignment and between separate consignment. Buyers would order with confidence if they could rely on grading standards.

Refrigeration was the major weapon available to fight deterioration of produce, said Mr Lili. The effective use of refrigeration would extend shelf-life, retard quality loss and reduce wastage caused by wilting and disease.

The most important step in cooling produce was the removal of field heat. If this was done effectively the subsequent temperature management of the produce in a cool store would be straightforward. A vacuum chamber, water and forced air were the major methods used to precool produce. In cool stores the temperature must be carefully selected to suit the product because some fruit and

vegetables suffered chilling injury if held at low temperatures, said Mr Lili. Another speaker at the seminar associated with the Horticultural Trade Fair, Mr Don Turner, export manager of Turners and Growers, Auckland, said that he was impressed by the amount of good land available for horticulture in Canterbury.

He advised farmers who were thinking about diversifying into horticulture to get their shelter established quickly, even if they then waited to see what crops to grow.

The horticulture industry would achieve $1 billion in exports by 1990 and he predicted that nashi pears and persimmons would become very important in the next decade.

The problems which surfaced in the asparagus industry this year would be overcome and Turners and Growers was planning to begin sea freighting of asparagus next season. Commenting on the move towards legislation to create licensing authorities for all horticultural products, should the growers want them, Mr Turner, who is also a member of the Horticultural Export Development Committee, said it made good sense to sit down and plan the future of an industry. He said export licence holders did not have “all the power” because licences could be revoked. A licensing system attempted to ensure that only exporters who had a commitment to the industry and were financially sound handled the produce in a competitive way.

The “muck and mystery” surrounding the concept of biological husbandry and organic farming was outlined at another session of the seminar.

Produce grown organically and with pests and predators existing in a balance, had caused a lot of

interest all over the world, said Mr R. A. Crowder, senior lecturer in horticulture at Lincoln College. The aims of biological husbandry included maintaining the long-term fertility of the soil, avoiding pollution from agriculture, producing foodstuffs of high nutritional value, and reducing energy inputs. New Zealand had a pretty healthy agricultural system using legumes, but the use of nitrogen obtained from artificial sources was rising. In the Northern Hemisphere farmyard manures were widely used for fertiliser, said Mr Crowder.

Organic principles were very important in horticulture because of the high fertiliser requirements. Using biological husbandly methods on a commercial scale could be done and people were making a living out of it, said Mr Crowder. For a conventional grower changing to organic principles, the first few years would be difficult. In the United States research had indicated that it would take five to 10 years to change successfully.

Extensive trials were also being carried out in Switzerland using biological hus-

bandry principles and also biodynamic techniques. The quality of these crops produced organically was superb.

Mr Crowder is involved with trials in biological husbandry at Lincoln College where globe artichokes have been grown successfully using these methods. Mr John Scott, a farmer from Hawarden, said he had been farming organically since 1965. The same principles for organic growing applied to cropping, horticulture and sheep farming.

When Mr Scott had taken over his farm the soil was in poor condition, it had no structure and was easily blown away by wind. To correct this organic matter was built up in the soil as quick as possible. Straw left over from crops was never burned but returned to the soil. Mr Scott uses a chisel plough and a sub-soiler and a pasture mix containing many different types of plants including lucerne and clover.

Stocking capacity on Mr Scott’s farm has increased since he took possession and grain yields have kept pace with other local producers.