Cotton growers gear up for low water year

27 August, 2003

___While the cotton industry lives in hope that rainfall and water availability will improve significantly between now and early October, Plan B is to revise management strategies to again cope with limited water availability._

Peter Birch, from B&W Rural at Moree, who has been addressing this issue in a series of hypotheticals in local grower meetings, revealed current thinking on the problem on the weekly Web on Wednesday video (20/08/03) on the CSDwebsite.

He said there was general consensus that unless growers were able to water the crop at least four times and preferably five, their water use efficiency in terms of either bales or dollars per megalitre would be eroded.

“The bottom line is that you have to have at least four or five waterings in a potentially tough season, otherwise you are really out of the ballpark as far as efficiency goes.

“You have to limit your acres to the amount of water that you have got. If you stretch them out (waterings), that is when you are really likely to suffer discounts, yield and efficiency wise,” he said.

He also warned: “If you stretch the first water too hard, then irrigate, then get a lot of rain, you will blow the crop away and it won’t pick up again,” emphasising the importance of keeping an eye on weather forecasts.

He also noted that last year, when growers deliberately adopted a long water stretch campaign, and succeeded in gaining a crop on only four waters, they did not necessarily suffer fibre quality discounts, although this was dependent on the timing of heatwave conditions.

In terms of planting date, while acknowledging the ideal planting window as late September to early October, he said it was important for growers in each area to assess the last feasible date for planting, with weather conditions and variety choice important factors in that debate.

In some areas, and with some varieties, the application of pix could also be important, he said, suggesting that growers aim for at least 150 fruit per metre before applying pix, which should then enable growers to bring the crop in quicker, with significant water saving benefits.

He suggested that if a low water year again evolves, growers should stick with varieties that help maximise both yield and fibre quality, and they are more likely to be indeterminate varieties with a full fibre quality package.

He concluded by saying that many growers may have to re-think their watering techniques, particularly in relation to siphon movement, field segmentation, watering time, and the use of moisture probes.

Further Information: Robert Eveleigh, John Marshall, Greg Kauter or Craig McDonald