RRRD004 progress update

November 2012

Science Summary:

-  Furrow sites in Home Hill recorded 13% higher deep drainage (263 mm) over the crop season compared to the drip irrigation (233 mm). Hence reduced deep drainage in drip irrigated sugarcane has been confirmed. However, the run-off in Home Hill site limited due to completely banked tail ends.

-  Low soil infiltration rate (5.42 mm/hr) has been recorded for micro-sprinkler block compared to higher infiltration rate (17.89 mm/hr) recorded for drip irrigated banana in the ferrosol soil.

-  Higher deep drainage noted in the Home hill site even for the drip irrigation site. Management of irrigation by frequent pulsing has been introduced this year to reduce the deep drainage from the drip irrigated crop of sugarcane.

-  Higher electrical conductivity in the soil with micro-sprinkler irrigation compared to drip is related to lower plant uptake in the sprinkler plots as the crop in this treatment is still establishing. Greater EC at depths below the effective rooting zone (65 cm), imply that those nutrients are more susceptible to loss from deep drainage.

-  Soil infiltration rates have a direct effect on run-off and deep drainage properties of the soil. At the current stage the infiltration rate in the drip plot is very high compared to the micro-sprinkler irrigation. It is very early to associate this to the irrigation treatment effect, as the crop with drip irrigation has substantially higher cover with plant debris (mulching effects). Research is ongoing.

-  Researchers note that although drip irrigation resulted in reduced Deep Drainage compared to furrow, these deep drainage values in sugarcane sites are still high. Opportunities exist for optimization of the drip irrigation to suit to the soil, crop, growth stage and weather which will be explored out of the variable site data being collected.

Progress Update:

-  The first biannual meeting of project team and other co-operators was held in December 2011.

-  Experimental sites have been set up (two sugarcane in N Qld and one with banana in C Qld, all with monitoring equipment all set up for automatic and manual sampling.

-  Data collection continued from two sugarcane trial sites in Burdekin. Crop at Home hill site harvest on 19-23 August (trial will continue on this site with ratoon crop for second season - 2012/13). The site at Clare will be harvested in Nov-Dec.

-  Two run-off events have been recorded from the banana trial site at Bundaberg. In the Burdekin run-off associated with rainfall was noted only on the furrow site. For the same rain event no run-off was noted for the drip irrigation block. We have progressed well with data and water sample collections from deep drainage in all trial sites.

-  In banana sites, piezometers for ground water, drainage lysimeters, and flumes with water height sensor for run-off control and sampling have been installed and data being collected. One new experimental area has been instrumented, with micro-sprinklers next to the drip site with banana in Bundaberg; active data collection has started from this block.

-  Information about drip irrigation in sugarcane and banana which will be mailed to growers currently adopting drip (10), flood (10) and overhead sprinkler (10). The outcome of this survey will also be presented and discussed in the field day. Field day planned for December will have a complete set of crop, soil and water data from one crop cycle, which will be more meaning to the growers to discuss on the field day.

-  Banana site at Bundaberg is now well instrumented and an additional block of Micro-sprinkler irrigation is establishing.

-  Plant, soil and water sampling from all trials continuing for second season.