Frost wreaks havoc on crops

UNSEASONAL frosts have wreaked havoc on local crops and some farmers need rain this weekend if they stand a chance of making a profit this season.

Growers in the Riverina have reported the mercury crashing to as low as -5 in the paddock, but prolonged periods below freezing have damaged cereals and pulses more than the extreme lows.

The frosts began on July 13 and 14, reoccurred for five days in a row between July 19 to 23, and more severe frosts hit again on August 3 and 6.

Some farmers have been hammered by stem frosts, which occur below -2 shortly after a rainfall event, freezing the stems of the plants and potentially killing any further growth.

Cereal and pulse farmer north of Griffith, Michael Pfitzner, grows wheat, barley, lupins, canola and field peas, all of which have been impacted to varying degrees.

Mr Pfitzner said rain was sorely needed this weekend for many crops to stand a chance of returning to profitability.

"It's going to be hard to say how bad it is at this stage, for some guys it's really quite bad and if they don't get a good rain soon yields will be drastically reduced," Mr Pfitzner said.

"If it stays dry it will be pretty devastating, but if it comes wet there's a possibility the crops will recover to profitable levels, even if they've been badly hit.

"In some ways it's uncharted territory because a frost this severe in this part of the growing season and with this level of damage I don't know whether we've monitored such an event all that much in the past.

"It's a big unknown, we don't really understand what the impact will be."

Mr Pfitzner said the reason the damage has been so acute was because the temperatures have stayed so low for so long.

"Once it gets below zero, how much lower it gets is not as critical as how long it stays below zero," Mr Pfitzner said.

"It's a bit like putting an ice tray in the freezer, if you take it out after an hour it may not be frozen but in 6 hours there's a fair chance it will be, and that's what happens on the stem."

The part of the plants which has been damaged is the tiller, or side shoot, and if all of a plant's many tillers have been stem frosted, the plant loses access to water and nutrient supply.