USDA Scientist Working with Texas Sorghum Growers to Reduce Water Use

Drought and resulting water shortages have driven many Texas farmers to turn to more hardy sorghum after suffering high losses trying to grow corn. However, growers unfamiliar with sorghum must decide if they will grow early-maturing varieties which are less vulnerable to drought due to their later planting time, or later-maturing varieties which can produce higher yields if they have adequate water.

To help farmers know how much water is needed for optimum sorghum production, Susan O’Shaughnessy, agricultural engineer with the U.S. Department of Agriculture’s (USDA) Agricultural Research Service (ARS) conducted three years of field trials evaluating yields and water use efficiencies of both early and late-maturing sorghum varieties under four different irrigation-deficit levels.

The team found that sorghum water-use efficiency was greatest at the 55% replenishment level, but even levels as low as 30% replenishment produced yields that were at least double those produced with no irrigation. At an 80% replenishment level late-maturing sorghum produced higher yields than early-maturing varieties, but early variety yields were sufficient to make it a viable planting alternative.

In addition, the team found that during times of drought, even though sorghum is more drought-tolerant than other crops, growers can risk near total crop loss without the use of at least some irrigation.

These findings should be able to help farmers in areas where rainfall is inconsistent or drought is common, to calculate the needed additional use of irrigation to gain the optimum sorghum yield.