Defence against frost damage

Press, Volume CX, Issue 32461, 23 November 1970, Page 13

Defence against frost damage

Trials of a new oil-fired burner system designed to protect orchards from frost have been so successful that the system will be placed on the market next year. During the severe weather in Central Otago which destroyed almost all the area’s apricot crop, one orchard with the new system had a 100 per cent “save” of its fruit Another orchard so equipped lost only a little fruit and this because of an unusual drift.

The orchard reporting the 100 per cent “save” was the research orchard of the Department of Scientific and Industrial Research, says the latest issue of “New Zealand Shell,” the Shell Oil Company’s journal. Hie traditional method of defence against frost has been to bum “smudge pots” —but these are inefficient in the use of fuel, require a relatively large labour force to operate, and produce a heavy pall of dense black smoke, the publication says. Development work on the

oif-reticulated heating system used experimentally at the two orchards began three years ago. The system at each orchard comprises a 2000-gallon storage tank from which gas oil is pumped through reticulation lines to burners. The new burners produce great heat but also achieve almost smokeless combustion. In Central Otago, in September, ground frosts reached 25 degrees during a threeday period, causing losses to growers estimated at sl.3m. Smudge pots cast a dense pall of smoke for 65 miles. In some cases, growers lit up to 1000 pots, each burning five gallons of diesel fuel in a 12-hour overnight period. Some orchardists used 4000 gallons of fuel a night, but could not produce enough heat to protect budding fruit trees.

The new anti-frost burners have been developed by the Shell Company, Kent Heating, Ltd, and the Plant Diseases Division of the D.5.1.R., the official body responsible for frost-fighting research.