Farm Table says:
This fact sheet summarizes desktop modeling work performed to benchmark water-use efficiency of wheat. The secondary aim was to model the sensitivity of changes in management practice on WUE.
- Maximum potential WUE was determined to be around 20 kg/ha.mm
- A trend for WUE to increase with decreasing N stress, which indicated that nitrogen supply and demand dynamics were an important driver of WUE in Tasmania
- Increasing the irrigation by 60 mm resulted in an average yield gain of 602 kg/ha and an increase in WUE of 0.4 kg/ha.mm of the control, with 15/30 years generating both an economic yield gain and an increase in WUE
- Increasing the total N rate from 70 kg N/ha (control) to 140 N/ha (unchanged irrigation of 20 mm), resulted in yield gains of 437 and 660 kg/ha, respectively.
- Increasing both irrigation and applied N resulted in much larger and more consistent gains in both yield and WUE. For example, average yield and WUE gains of 2119 kg/ha and 1.9 kg/ha.mm were reached with an additional 120 mm irrigation and 140 kg N/ha of fertilizer with positive gains in both occurring in 22/30 years.