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Consider Sorghum

Corn’s price plunge is giving this drought-tolerant crop a chance to crack crop rotations again.

If corn’s high input costs make you queasy, another grass crop exists that might fit some of your acres. 

It’s sorghum.

“We aren’t promoting this as a corn-vs.-sorghum choice, but sorghum can be a good addition to a rotation,” says Scott Staggenborg, director of product portfolio and technology advancement at Chromatin, a Lubbock, Texas, firm specializing in sorghum genetics and development. “With low crop prices, everyone is scrutinizing input expenses. Input costs are often $50 to $100 per acre lower for sorghum than for corn.”

Where sorghum may fit

Earlier this decade, stratospheric corn prices prompted farmers to push sorghum out of their rotations to make room for corn in parts of the Great Plains. Receding corn prices have snapped back sorghum economics, says Staggenborg.

“In my lifetime, I’ve seen people move away from sorghum two to three times,” says Staggenborg. “Then we have a two- to three-year drought, and everyone remembers why we have sorghum.” Its smaller stomates, lower transpiration rates, and waxy leaves help sorghum endure drought.

Sorghum may also fit some soils in Corn Belt states like Iowa, Illinois, and Indiana. Though these states are blessed with rich soils, farmland underlain by sand and gravel with a corn yield potential under 120 bushels per acre also exists. On these soils, sorghum can be a better economic choice than corn.  

“The yield threshold between corn and sorghum is around 114 bushels per acre,” says Staggenborg. If corn consistently yields below 114 bushels per acre, sorghum can be a better economic choice.”

How to grow it 

Breeding is one area in which sorghum has paled compared with corn. On average, corn yields annually increase an average of 1.82 bushels per acre, according to an analysis by Scott Irwin and Darrel Good, University of Illinois agricultural economics. Staggenborg notes a major reason for this is the billions of dollars that seed companies have poured into corn breeding. 

Sorghum breeding, though, is gaining steam. Companies like Chromatin have launched better hybrids that tolerate sugarcane aphids and resist disease. 

Seed still costs less than corn, too. “Seed costs for sorghum are $12 to $15 per acre compared with seed corn costs that are often over $100 per acre,” says Staggenborg.

Still, sorghum needs inputs like nitrogen (N). The ratio of N needed to produce a bushel of grain is akin to corn’s 1.2 pounds of N per bushel, says Staggenborg. 

Weeds do grow in sorghum, too. Unfortunately, herbicide options are limited compared with the myriad corn and soybean herbicides. 

“We still rely heavily on preemergence herbicides,” says Staggenborg. “In sorghum, there has never been an effective system that is post only.” Still, preemergence and postemergence herbicide options exist. Including sorghum in a rotation is also a way to stymie glyphosate-resistant weeds, since no glyphosate-tolerant trait exists in sorghum. 

Most farmers plant sorghum with a row-crop planter, but they also can air-seed sorghum. Seeding rates vary according to rainfall.

“If you farm in a drier environment and your yield goal is less than 80 bushels per acre, plant 35,000 seeds per acre,” says Staggenborg. “In other environments, though, I recommend planting 70,000 plants per acre and up to 100,000 plants per acre under irrigation.”

Staggenborg says sorghum genetics and agronomics are set to improve, similar to the position corn was in 20 years ago. “We want people to think about it as part of their rotation,” he says. 

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