Statewide
This continues a series to examine production of grain sorghum vs. corn in relation to dryland and limited water conditions as well as water-use efficiency of grain sorghum vs. corn.
Water use efficiency (WUE) is debated frequently among research, educators, and producers. When you read reports in research and farm publications, sometimes either of two mistakes are made in the data and discussion—Results are given and discussed for:
- Total crop yield divided by total water
- Total yield divided by irrigation water applied
The flaw in each is, in the first case, there is a certain amount of water required (stored soil moisture, rainfall, irrigation) to achieve that first bushel of grain yield per acre. In the second case, the flaw dismisses the contribution of soil moisture and rainfall.
From an agronomic perspective, we want to know the following:
What is the incremental change (increase) in yield per unit of available water?
Again, from an agronomic perspective, we also often overlook this:
How much available water does it take to produce that first bushel of grain?
If you get an additional 2” of rain (one rain, or over the course of the season) on your crop, what is the increase in yield? If you use an additional 2” of irrigation, what is the yield increase due to that water?
In the first question corn grain yield is greater than grain sorghum, but in the second grain sorghum has a strong advantage over corn.
There are many factors to discuss, and I will begin that in our next Sorghum Tip.
