Four Tips for Sorghum Planting Success
Grain sorghum planting is in full-swing throughout the Central Plains, and as it moves northward, there are some practices successful sorghum growers use to get the crop off to a good start.
1. Plant the right hybrid.
Choose the hybrids that best fits your geography and environment, advises Scott Staggenborg, director of technical services for the sorghum genetics firm Chromatin. While yield is the top goal, be cognizant that the hybrid you selected last fall may not be the best fit for this spring’s climactic conditions. You may have your hybrids picked out already, but in most cases, “it isn’t sold until it is in the ground,” Staggenborg says.
Crop maturity lessens the farther north you go, so producers in northern Nebraska and South Dakota will need earlier-maturing hybrids, particularly if planting runs later. Also, keep in mind the precipitation outlook. “Farmers in west Texas, for example, plant medium to medium-early hybrids because when it gets dry in the summer, it is better to have the crop finished earlier,” Staggenborg says.
Seed supplies are good, so producers still have time to select hybrids. Use regional, multiple-year yield data as a guide for hybrids that fit in your area. Another trait producers should look at is the ability of a hybrid to withstand lodging. A stay-green or standability performance factor is one indicator that the crop will not fall prior to harvest.
Adding a seed treatment such as Cruiser to sorghum seed is a good idea, particularly when planting into no-till, he adds.
2. Use a pre-emerge herbicide.
Curtis Thompson, weed management specialist at Kansas State University, says a pre-emerge herbicide program is a must in controlling herbicide-resistant weeds, problem broadleaves and – the bane of all sorghum growers – grassy weeds.
“There are enough tools in a sorghum producer’s toolbox to do an effective job in weed control,” Thompson says. The first rule, he adds, is to not plant sorghum where shattercane or johnsongrass is a known problem.
A pre- and post-emerge program using the Callisto mesotrione products - either Lexar or Lumax – may be expensive, but is effective at providing season-long control of many annual grasses and broadleaf weeds. Lawrence, Nebraska farmer John Dolnicek, says a split application combined with glyphosate a week to 10 days prior to planting, combined with a second application of the same prior to emergence, helps fields “start clean and stay clean.”
For in-season control of broadleaves, Thompson says a post-emerge application of Huskie – a premix of pyrasulfotole and bromoxynil – can be made after the crop reaches the three-leaf stage and before it is 30-inches tall. Huskie needs to have a half-pound of atrazine added to the tankmix. However, do not apply to ground previously treated with Lumax or Lexar, Thompson warns.
3. Use enough fertilizer.
Grain sorghum is oft-considered a low-maintenance crop, but it may require more nitrogen than you think.
“We often hear from farmers who thought their sorghum should yield better, but they didn’t put on enough nitrogen,” Staggenborg says.
Ideally, producers should base fertilizer recommendations on soil test data. Failing that, research at Kansas State University shows that sorghum requires 1.6 pounds of nitrogen per bushel of expected yield, assuming 2.0% organic matter. By the time nitrogen credits are accounted for, a rule of thumb is apply one pound of nitrogen per bushel of expected yield.
If planting into no-till, a few gallons of starter fertilizer at planting will give the crop a boost in cool, damp soils. Starter is not as important in conventional tillage systems, he adds.
Keep in mind the crop following sorghum, too. Soil scientist Ray Ward of Ward Laboratories in Kearney, Nebraska, says sorghum that yields 120 bushels per acre takes from the soil 102 pounds of nitrogen, 42 pounds of phosphorous, 30 pounds of potash, 14 pounds of sulfur and one pound of zinc.
4. Seed it correctly.
Today’s planters are extremely accurate. But many farmers still use grain drills or air seeders to plant sorghum, and they need to know how much seed to apply per acre.
“It becomes a challenge to get the correct seeding rate because farmers are using volumetric measure, and not every hybrid contains the same number of seeds per pound,” Staggenborg says. “Read the tag, and make sure you get the correct number of seeds per acre.”
Staggenborg has the following seeding recommendations based on yield objectives:
- Low Yield, Dryland: 30,000 seeds per acre
- Medium to High Yield, Dryland: 70,000 sees per acre (caveat: shorter-season environments may want more seeds per acre to prevent tillering).
- High Yield, Irrigated: 90,000 seeds per acre.
He recommends planting at least 1.5-inches deep, as shallow planting results in uneven stands. Be sure to account for residue when setting seeding equipment; a mat of residue can result in shallower planting than expected.