Cotton Irrigation Management Update

04 August, 2006

Cotton growers have been utilising irrigation management software HydroLOGIC since 2003, following its development by CSIRO and the Cotton CRC.

In recent seasons, the program has been validated by a series of industry trials that have emphasised its importance as a management tool in optimising irrigation scheduling and in saving irrigations, with no detrimental impact on yields.

Speaking on the CSD weekly Web on Wednesday video, Dirk Richards from CSIRO said practical experience with using HydroLOGIC in the field has stimulated interest in expanding the software to encapsulate wider climatic variability, such as extremely hot or wet seasons.

“We are also looking at whether we can develop a similar sort of concept for other crops because most cotton growers also grow other crops, such as cereals and legumes.

“We are also working on an integrated project with AquaTech Consulting, seeing whether we can value-add our HydroLOGIC, with their WaterTrack and Irrimate software, to provide even further gains in crop management understanding, water use efficiency and yield.”

Web on Wednesday was also given an update on trials involving the response of Bollgard® II cotton to water stress at different growth stages compared with conventional varieties.

Steve Yeates, also from CSIRO said: “With full irrigation, at ACRI where we have been getting yields of around 10 bales per hectare, Bollgard® II is slightly ahead in terms of bales per megalitre because Bollgard® was actually setting its fruit in a shorter period of time so therefore it is using water for less time.

“When Bollgard® crops were placed under stress around cutout, (4 ½ nodes above white flower), yield dropped off compared with conventional, because Bollgard® crops had a higher fruit load at this time.

”However, when Bollgard® and conventional crops were both stressed even later, ten days after cutout, by denying the final two irrigations, the Bollgard® II crops actually had higher yields.

“There are two reasons for that. One is that we had rain. It was 100 mm in that time which helped, and the second was the greater boll load of the Bollgard®II meant that it only had to finish bolls off, whereas the conventional still had flowers to set and bolls to fill. So it wasn’t able to compensate as well because it had insufficient water.

*“ However, *in terms of its reaction to stress compared to conventional it’s more sensitive towards cutout, and I think you have got to be much more careful with Bollgard®II stretching irrigations once you start to get a bit of a fruit load on it.

“Bollgard®II was slightly more water use efficient plant under full irrigation, but we need to do some more research at higher yield levels,” Steve Yeates said.

Further information: Dirk Richards:

Steve Yeates: