For an irrigator, investments in on-farm water infrastructure that increase the marginal productivity of water may improve use efficiency. However, increasing on-farm water use efficiency invariably diminishes return flows, compromising the ability to maintain sufficient water flows in streams...

Helicoverpa spp. (heliothis) are a major insect pest of cotton, grains and horticulture in the Murray‐ Darling Basin. Climate change is likely to make conditions more favourable for heliothis. This could cause regional comparative advantages in irrigation systems to change as management costs...