FIGHTING FROST IN ORCHARDS

Hawke's Bay Herald-Tribune, Issue 171, 6 August 1937, Page 8

FIGHTING FROST IN ORCHARDS

Our Own Correspondent.)

Coal-Briquette Heaters the Most v Useful Method £5 AN ACRE A SEAS0N

(From

WELLINGTON. This Day. The use of coal-briquettes is likely to be the .most practical method oi i'rost-fighting in orchards, in the opinion of Mr Lloyd Williams, orchard inspector in Central Otago. Mr Williams recently jnade extensive investigations into frost prevention in California. The methods employed there, which consisted chiefly of the use of iuel oil, were outlined to the conferenee of the New Zealand Fruitgrowers' Federation at Wellington yesterday by Mr Williams. - The conferenee decided that Mr Williams should be made -available by the department to visit the various districts affected by frost and address growers in frost-fighting measures. The prevention of heat' losses, explained Mr Williams, had been found in California to have no practical valuo for frost-fighting in orchards. The principle of additional heat was the only means of combating trosts. Smoke was only incidental to orchard heating, having no effect on other than very light frosts. Generally speaking, it had proved detrimental rather than helpful in the prevention of frost. California Us£s Oil Heaters, ttefer&ng to the use of oil, Mr Williams said that last season in California 70,000,000 to 80,000,000 gailons were consumed in the fighting oi frosts. This amounted to 2,OUO,0OO drums, which, if placed, end to cnd, would extend from Invercargill fco Whangarei. llseful work was being done in California by the weather bureau in the prediction of frosts and in advising growers of the time to light up and how long to keep heat applied. To a certain estent .watering by means of irrigation had been of assislance in the case of small frosts; it was a useful standby. Touching upon tho nses of electricity, Mr Williams said that as a direct means of heating it had been found to be impracticable. A total of 1000 h.p. was necessary to heat up one acre, which made it prohibitive. Wind machines also had been found to.be impracticable, and he regretted to have to dash the hopes of of . those who anticipated that they would be a suceessful means of frost-fighting. Mr Williams then dealt with the . uses of fuel oil and of heaters. This method, he said, necessitated about 140 heaters an acre. The most advantageous method was the placing of these heaters in the centre between trees so that each tree really received the effect from four heaters. Low Cost of Oil. A system of central heating installed in a citrus orchard was most effective, and the running costs were extremely low. The drawback, however, was the heavy initiai cost. For the purposes of heating, the oil used in California cost oniy about one- quarter of what it would cost the New Zealand orchardist. The low cost of oil gave it a very great advantage over the use of solid fuel. As if would assist a New Zealand industry, Mr Williams said, he had investigated the uses ot coal in the form of briquettes for heating. Ihese had beeu found to be quite satisfactory more especialiy when a small percentage of nitrate of, soda was used to assist combustion. The cost of briquettes landed in the orchards, however, was so far greater than. he had qnticipated. It had been found that bettcr heat; was . obtained from briquette heaters than from oil-burners and he considered that it would be found to be a practical means of heating and less expensive than the use of oii. Speaking generally of heating in orchards, Mr Williams said that in California, owing to the largo amount of capital invested, growers had not given a great deal of consideration to methods other than those of oil-burn-ing. iteplying to a question Mr Williams explained that on an average period of burniug the cost per season for heating with briquettes was approximately £5 an acre. The conferenee expressed its appreciation to the Government for sending Mr Williams to California to make investigations into the prevention of damage by frosts. It was also decided to ^quest that Mr Williams should visit the various districts at the earliest opportunity and address growers uij frost-fighting methods .