FIGHTING FROST.

Hauraki Plains Gazette, Volume XXXIX, Issue 5223, 6 January 1928, Page 4

FIGHTING FROST.

THJE ORCHARIHSTS’ ENEMY.

ADDRESS BY DR. KIDSON.

Although not giving cause, for any great concern in this district, frosts in many other parts of the Dominion give a good deal of trouble. To orchardists “Jack Frost” is an eneffny ; in fact perhaps the prchardists’ greatest enemy. Recently, at the invitation of the Hawke’s Bay Fru;t-grow-ers’ Association, the director of the Meteorological Department ,( Dr - E - Kidson) delivered an .address to meimbers of the association in Hastings on i'lrost 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' onej. 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 suck down the air some 35 feet or s.o above the ground. The air is heated and then discharged eithe.r 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 force out the air stream for any considerable distance, especially against the, natural drift in the orchard. The lecturer showed a picture of two ojlburning heaters used to combat frost, There was no doubt that crude oil was the most convenient fluel for orchard heating, but in Ne,w 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 difficult’es 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, &. grower would be advised to work out thq cost and see if it would be worth while. About 100 pail heaters an acre were necessary, .evenly, spaced in parallel rows throughout tile 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 bo double the numbor ot 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 apd 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 accurately known, and giving advice on the taking of temperature, Dr. Kidson concluded by giving the following summary of hints :—

“Each grower should study his own problem, apd estimate how frequently and to what extent he, is. liable to suffer loss from frost.

“If his losses are serious he should study his location ; not what are the probable sources of hold air ; test its flow on cold nights by means’ of the 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 the lower the 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 thei 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 as to whether heating is likely to pay. Possibly some other forrii 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.”