THE ORCHARDISTS’ ENEMY.

Putaruru Press, 5 January 1928, Page 3

THE ORCHARDISTS’ ENEMY.

FIGHTING FROST. Address by Dr. Kidson. Although not giving cause for any great concern in vVeilington, irosts in many other parts of the Dominion give a good deal of trouble. To « ; chardists “Jack Frost" is an enemy; A n fact, perhaps the orchardists greatest enemy. Recently, at the invitation of the Hawse's Bay Fruit-growers’ Association, the director of the Meteorological Department (Dr. E. Kidson) delivered an address to members of the association in Hastings on frost fighting. After describing the formation of frost,"Dr. Kidson stated that it might seem possible to stir up the air sufficiently to prevent the formation of frost. Investigations, however, had shown that this scheme was not a sound one. To be successful it would be necessary to generate a moderate wind all over the orchard, and that would be far too costly. Machines to Generate Wind-

The lecturer showed lantern slides of various wind-generating machines in America, the principle of which was for a high vertical pipe to uck down the air some 35 feet or so above the ground. The air is heated and then discharged either along the ground or just over the tops of the trees. The results obtained from the machines were interesting, although the experiments were a failure in that it was not possible to out the air stream for r.ny considerable distance, especially against the natural drift in the orchard. The lecturer showed a picture of two oilburning heaters used to combat frost. There was no doubt that crude oil was the most convenient fuel for orchard heating, but in New Zealand it was expensive. Other fuels had been used, including coal in various forms, but it had generally been found rather troublesome owing to the difficulties of lighting and maintaining a good burn. Should cheap briquets become available, however, they would almost certainly be found to be the most convenient form of coal to use. Use of Heaters.

Before undertaking heating a grower would be advised to work out the cost, and see if it would be worth while. About 100 pail heaters an acre were necessary, evenly spaced in parallel rows throughout the area to be protected. The positions should alternate, a pail in one row being opposite a gap in the next, and it' was also well lo double the number of heaters on the outside rows to windward. On some nights it might be found necessary to light only a quarter or half of the heaters. The most dangerous period was the two hours centred about sunrise, and the whole labour and cost of heating would be wasted unless it could be prolonged over the danger period. Summary of Hints. After stating that the temperature of orchards must be "curately known, and giving advice on the taking of temperature, Dr. Kidson concluded by giving the following summary of hints: 11 Each grower should study his own problem, and estimate Low frequently and to what extent he is liable to suffer loss from frost. “If his losses are serious he should study his location; note what are the probable sources of cold air; test its flow on cold nights by means of f he smoke from small fires; note the direction and rate of drift and 'whether it rises or clings to the ground. The slower the drift and "he lower tno smoke hangs, the easier will the frost be combated. “With the information so gained he may find that considerable protection may be provided by means of a high wall or a tree bank on the windward side of the drift. “Or he may find that certain portions only of his land are likely to be affected. It may be advisable to abandon these portions, or grow only the hardier crops, or the more frost resisting varieties thereon. “It may prove that fruit growing is unlikely to be profitable on the area, and the sooner the attempt is abandoned the better. “Seek the best expert advice available as to equipment and methods. “The cost of heating can thus be worked out in detail and a final decision taken as to whether heating is likely to pay. .Possibly some other form of insurance would be more satisfactory. “The question as to whether heating will be successful and economical cannot be decided in one year. It will certainly take several years."