Abstract
The cost of irrigation water accounts for 30-38% of the total variable costs of rice production in the Murray and Murrumbidgee Valleys. Rice production consumes a substantial proportion of the available supply of irrigation water. Any water management practice that has the potential to reduce water use and/or increase water use efficiency should be investigated. This project evaluated two approaches that may increase water use efficiency of rice – delayed flooding and a water management strategy termed mid-season ‘drain’. Water use was quantified and agronomic performance of the rice crop monitored. Delayed flooding involves intermittent irrigation of the crop until about ten days prior to panicle initiation. The scheduling (and number) of intermittent irrigations will be determined by the growing season temperatures. In the experiments reported here the combine sown treatments received eight irrigations as well as the first flush which initiated germination. The aerial sown treatments received three or four irrigations once the crop had established. The time taken for establishment (3-4 leaves) ranged from 34-43 days. Mid-season ‘drain’ involved removing surface water from the crop for about seven days towards the end of tillering. The rice plants experience visible moisture stress before the flood is re-applied. Plots grown with delayed flooding produced equivalent yields to the fully ponded control. Water use was reduced by 8-18%; thus water use efficiency was increased. Mid season ‘drain’ increased grain yields by 6, 10, and 9% for the three growing seasons covered in this report. Whilst none of these increases in yield were statistically significant there is sufficient evidence of an increase in grain yield when the crop experienced a mid-season ‘drain’ to warrant further investigation. In commercial crops, when mid-season ‘drain’ is practised, a reduction in water use of about 50 mm (0.5 ML/ha) could be expected. Results from this project and from project 1204(A) indicate that where water use is the total water balance ie. includes rainfall and change of storage in the soil profile, water use efficiency from a fully ponded crop is unlikely to exceed 7.5 kg/ha/mm (0.75 t/ML).
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Claims 6
Claim · model-written summary
Delayed flooding produced equivalent yields to a fully ponded control.
- Taxon
- Rice
Oryza sativat0 - Treatment
- delayed floodinge0
- Outcome
- yieldse0
- Direction
- equivalente0
- Comparator
- fully ponded controle0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Plots grown with delayed flooding produced equivalent yields to the fully ponded control.”
t0“Rice”
Claim · model-written summary
Delayed flooding reduced water use by 8-18%.
- Taxon
- RiceOryza sativat0
- Treatment
- delayed floodinge0
- Outcome
- Water usee0
- Direction
- reducede0
- Value
- 8-18%e0
- Comparator
- fully ponded controle0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Plots grown with delayed flooding produced equivalent yields to the fully ponded control. Water use was reduced by 8-18%; thus water use efficiency was increased.”
t0“Rice”
Claim · model-written summary
Delayed flooding increased water use efficiency.
- Taxon
- RiceOryza sativat0
- Treatment
- delayed floodinge0
- Outcome
- water use efficiencye0
- Direction
- increasede0
- Comparator
- fully ponded controle0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Plots grown with delayed flooding produced equivalent yields to the fully ponded control. Water use was reduced by 8-18%; thus water use efficiency was increased.”
t0“Rice”
Claim · model-written summary
Mid-season drain increased grain yields by 6, 10 and 9% across three seasons, without statistical significance.
- Taxon
- RiceOryza sativat0
- Treatment
- Mid season ‘drain’e0
- Outcome
- grain yieldse0
- Direction
- increasede0
- Value
- 6, 10, and 9%e0
- Qualifier
- three growing seasonse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Mid season ‘drain’ increased grain yields by 6, 10, and 9% for the three growing seasons covered in this report. Whilst none of these increases in yield were statistically significant”
t0“Rice”
Claim · model-written summary
Commercial mid-season drain was projected to reduce water use by about 50 mm.
- Taxon
- RiceOryza sativat0
- Treatment
- mid-season ‘drain’e0
- Outcome
- reduction in water usee0
- Value
- about 50 mm (0.5 ML/ha)e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In commercial crops, when mid-season ‘drain’ is practised, a reduction in water use of about 50 mm (0.5 ML/ha) could be expected.”
t0“Rice”
Claim · model-written summary
Water use efficiency under full ponding was judged unlikely to exceed 7.5 kg/ha/mm.
- Taxon
- RiceOryza sativat0
- Treatment
- fully ponded crope0
- Outcome
- water use efficiencye0
- Value
- 7.5 kg/ha/mm (0.75 t/ML)e0
- Qualifier
- unlikely to exceede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“water use efficiency from a fully ponded crop is unlikely to exceed 7.5 kg/ha/mm (0.75 t/ML).”
t0“Rice”
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