“Aim a little higher with grain sorghum expectations,” recommends Texas AgriLife Extension agronomist Calvin Trostle. “Consider what you could do a bit better.”
Trostle, speaking at the Concho Valley Cotton Conference, in San Angelo, Texas, said seeding rate, fertility, rotation and weed control all play a role in grain sorghum production.
Planting on a bed also may limit grain sorghum success. “Grain sorghum roots do not like hot weather, and we want those brace roots in the soil.”
Planting too early could result in stressed seedlings. “We prefer that the soil temperature 10-day average be at 65 degrees F with 62 degrees the lower limit.”
He strongly urged farmers not to “over-populate the field. Planting too many seeds per acre is a mistake. A producer with proper seeding rate can make 1,200 pounds per acre (in stress conditions), and his neighbor makes hay.”
Concho Valley farmers should consider a 30,000 to 35,000 seed-per-acre planting rate with a final plant population ranging from 21,000 to 28,000 per acre. “That population should produce good results under a wide range of conditions.”
With irrigation and a good water resource, producers might bump the seeding rate up. “But if a farmer has doubts about bumping up his seeding rate, don’t! Less is more. Less seed means more yield.”
Trostle said producers may need to plug up some drills to get the proper seeding rate, and he also advises them to check uniformity with vacuum planters after the crop emerges to see if population is what they expected.
If you are enjoying reading this article, please check out Southwest Farm Press Daily and receive the latest news right to your inbox.
Nitrogen fertility also makes a difference, Trostle said. “You don’t get something for nothing, at least not for long. Sorghum nitrogen fertility is important.”
The benchmark is two pounds of nitrogen for each 100 pounds of yield goal. That’s combined sources—applied and nitrogen available in the soil. He recommends a typical soil sample at zero to six inches and another deeper test for nitrogen. “Deep nitrogen can be credited 100 percent to the crop requirement,” he said.
At least 75 percent of the crop’s nitrogen demand should be available by heading. Trostle said growers should apply some pre-plant or at-planting and sidedress more 30 to 35 days after planting.
Weed control improved
Weed control has long been a challenge for grain sorghum producers. That has become a bit easier, Trostle said, with a new herbicide, Huskie. “A few farmers used it in 2011, and a few more tried it in 2012. A former colleague said Huskie is the best new herbicide he had seen in 30 years.”
Target weeds include Palmer amaranth, morningglory, devils claw and Russian thistle. Best results come from application to weeds four inches tall or less.
Huskie does not volatize; it will drift but not to the degree that other herbicides will.”
Huskie is a selective post-emergence herbicide. “It works best applied with Atrazine,” Trostle said. “It is not a stand-alone treatment.”
He also recommends a stewardship approach. “Just because it is a good over-the-top option doesn’t mean farmers should neglect pre-plant or pre-emerge weed control.”
Cotton farmers have plant-back restrictions, which require an 18-month break before planting cotton. A nine- to 10-month plant-back option is being considered. For small grain, the plant-back limit is only a month.
Trostle said Huskie may result in some mostly cosmetic plant injury.
In addition to offering farmers a profitable crop option, Trostle said grain sorghum also provides soil enrichment benefits, especially with reduced tillage. Stubble management is important.
“Turning stubble under doesn’t necessarily increase soil organic matter,” he said. “But the roots do. Should growers mow it off? They can plant cotton to the side of grain sorghum stubble or down the row.”
He said the best option is to let stubble stand for as long as possible. “The only way to increase soil organic matter is to use a reduced tillage system.”
Grain sorghum rotation benefits cotton, he added. “Rotation benefits amount to a 7 percent to a 12 percent advantage.”
Growers may have a tougher time finding their favorite hybrids this year, Trostle said, although recent jumps in cotton prices may result in some growers returning sorghum seed. “Check with your dealer,” he advised. Growers also should be prepared to pay more for seed, up to $50 or $60 a bag. “That’s not a significant cost in the big picture and it makes sense to pay an extra $1 to $3 for a good hybrid. I don’t like cheap seed. Growers should buy the best they can get.”
He also said that herbicide tolerant sorghum hybrids should soon be available. Those options will offer tolerance to ALS herbicides (Accent and Glean, for example). “The target date for release is 2014 or 2015. But the first herbicide tolerant hybrids may not have the yield potential compared to the standards.”
Grain sorghum, Trostle said, offers Southern Rolling Plains farmers, as well as farmers across the Southwest, a viable crop alternative. But to take full advantage of the crop’s drought tolerance and yield potential, farmers must bump up their expectations of what grain sorghum can do and manage it accordingly.