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No. 25 (December 1958)
– 46 –

Better storage and more care in handling of crops will provide extra income for growers.

HIGHER RETURNS FROM KUMARA

Horticulturist, Department of Maori Affairs, Gisborne

Improvements in storage methods will do more than anything else to increase the value of crops such as kumaras, potatoes and pumpkins. Distribution will be made more efficient, which will have an important bearing on returns for the growers' efforts.

We must modernise our storage as many are already doing with kumaras, to get away from the old methods, which in America have been shown to cause up to 30% loss by decay. They say that with careful handling and modern methods of storage, losses should be less than 5% (much less, I think).

Handling

Few products are more easily injured than the kumara and it should be as carefully handled as the apple. American growers make sure their pickers have their finger nails shortened back to prevent damage to the kumara tubers. Once bruised, organisms causing decay will enter the bruised part and even if decay does not set in, the bruised area becomes discoloured and hard, thus injuring the appearance and reducing the quality.

Layout of interior of storehouse

Large stores should be divided into either small rooms or bins so that each room or bin can be filled in a day or two at the most, otherwise the completion of the curing with the necessary shrinkage will be uneven. Kumaras have to lose about 6–8% only of their original weight.

Comparison of large bins and smaller containers

It is often asserted that containers are better than bins because when decay sets in it is likely to be confined to the container, but in bins the decay may spread. There is considerable bruising with the extra handling in bin storage and in the dumping of the kumaras into the bins. With ideal conditions and very careful handling, our losses in bin storage should be practically nothing. Where less care in storage is taken, then I would say storage in boxes would be better. Any extra efforts towards careful handling will be rewarded. The use of shelves to reduce the depth of the stack and the incorporation of wood shavings, need to be considered.

Sorting versus non-storting

It has been generally believed that when kumaras begin to decay in storage they should be sorted to pick out the diseased ones. Experiments have proved, however, that it is inadvisable to distub them to pick out those that are decaying. There is apparently no justification for expecting any advantage from sorting to remove decaying tubers.

It is desirable to store the seed stock in a separate room or bin so that it may remain undisturbed until planting time.

Reminders re Storage Houses

  • * Build them or improve them so that they are vermin-proof, well insulated, draught-proof but with adequate ventilating systems which will shut tight when not required.

  • * Wood is a fairly good insulator and can be used to insulate walls and roof but if insulating boards are available, these would even be better still. Building paper should be used to stop draughts and when used sufficiently will help with the insulation and this is important as good insulation helps in maintaining a fairly uniform temperature regardless of the fluctuations outside.

  • * Windows should be as few as will provide light for the workmen. Excessive light favours sprouting, and large glass areas permit rapid loss of heat.

  • * Shed hygiene and protection against insects should be considered. Diseases are carried by spores which can be controlled by a copper or lime sulphur spray when the store and boxes are not in use. Insections spoil tubers and carry disease spores and can be checked by the newer forms of D.D.T. Spray such as Malathion or Trimort. Derris powder used wisely during storing time will keep a check on various tuber eating insects. All methods of insect control also will no doubt check “borer” in the timber inside your storehouse. Bulk derris can be bought a about 2/- per lb and this is the best way o buying it.

Progress with kumara storage will no doub give an important lead to pumpkin and potato growers in the future.