Farm Table says:
What is the problem?
The impact of climate change on cotton production has been of interest since the 1990s. Experiments and modeling have been conducted to address this important issue. Previous studies, including Mauney et al. (1994) have found that cotton water use efficiency would increase in a high CO2 environment under different levels of irrigation and the increase in water use efficiency (WUE) was due to an increase in biomass production rather than a reduction of water use.
What did the research involve?
Local climate scenarios for key cotton production areas in eastern Australia were modeled. These scenarios were then linked to a cotton model to quantify their potential impacts on cotton lint yield, water use, and water use efficiency (WUE) under irrigated and rain-fed conditions in 2030.
What were the key findings?
Simulation results showed that:
- Season temperatures will increase 1–1.2 degrees Celsius and rainfall will increase 2–16% across locations
- For irrigated cotton crop water use will increase 0–4% in more than half of the cases (the combinations of the number of locations and water supply levels)
- Cotton lint yield will increase 0–26% and WUE will increase 0–24% in most of the cases due to counteractive effects of elevated CO2 and future climate
- For rain-fed cotton water use will increase 2–8% at Emerald and Narrabri and decrease by 5 to 2% at Dalby and Moree
- Cotton lint yield will increase 4– 26% in most of the cases and WUE will increase 2–22% in all cases.
- For irrigated cotton, it was found that water supply level with 2 ML/ha generated the greatest positive effects to future climate scenarios across locations except at Dalby where 4 ML/ha was greatest.
- For rain-fed cotton, a solid planting configuration had the greatest positive response to future climate scenarios at Emerald, Dalby, and Moree while double skip planting generated the maximum benefit in lint yield at Narrabri.
For irrigated cotton, a water supply level of 2 ML/ha generated the greatest benefits to cotton lint yield and WUE under future climate scenarios.