Growing Grain Sorghum: Expert Recommendations for Planting and Management

Grain sorghum, a warm-season grass crop, is a versatile option for farmers in hot and dry climates. Unlike other major crops, grain sorghum thrives in drought and heat conditions, making it well-suited for the Midsouth region’s dryland fields or areas with marginal productivity. However, it’s important to note that sorghum is sensitive to low soil pH. Farmers can also consider planting sorghum in May and June as a backup when rainfall delays planting or as a double-cropping option after wheat or other small grains. Not only does grain sorghum offer several benefits in a rotation system with soybean, cotton, or other crops, but it also has its limitations in the region.

Essential Planting Practices

To ensure a successful sorghum crop, it is crucial to start with a weed-free seedbed. This means controlling all weeds through tillage or a preplant burndown application before planting. While postemergence herbicide options for sorghum are limited, it’s worth noting that sorghum doesn’t have herbicide-resistant traits that allow for non-selective herbicide treatments. Thus, it’s essential to focus on weed control before planting to avoid issues later on.

Optimal Planting Conditions

While sorghum responds well to early planting, its seedling vigor and hardiness are not as robust as corn. Soil temperature plays a crucial role in germination rate, with sorghum requiring soil temperatures above 65°F for rapid and reliable emergence. Assessing the germination conditions by measuring soil temperature early in the morning at the target planting depth is essential. Additionally, sorghum seedlings are vulnerable to soil saturation during establishment. To enhance the establishment of a healthy stand, consider planting on raised beds and when temperatures support rapid growth.

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Determining Planting Density

Grain sorghum productivity doesn’t significantly vary with planting rates. To optimize productivity in dryland sorghum, aim for a modest population goal of 40,000 to 70,000 plants per acre. This allows sorghum to better tolerate stress during July and August without sacrificing yield or plant health. If irrigation is available, population density can be increased to 70,000 to 80,000 plants per acre. However, keep in mind that sorghum’s yield potential is about 30% less than corn, so planting corn may be a better option if irrigation is available. Sorghum can be grown in various row widths or patterns, but rows 30 inches or less tend to be about 10% more productive than wide rows.

Grain Sorghum Planting

Planting Depth and Herbicide Treatments

Sorghum seed should generally be planted 1.25 to 1.5 inches deep, considering factors such as soil texture and moisture content. Deeper planting is suitable for sandy soils, particularly when soil moisture is scarce. However, deep planting can hinder stand establishment in cool and wet conditions. For successful weed control, preemergence herbicide treatments are crucial in sorghum production. While postemergence herbicide options for grass weed species are limited, timing plays a critical role in herbicide application. Applying residual herbicides at planting is vital to prevent weeds from emerging simultaneously with sorghum, which can be challenging to control and negatively impact sorghum yield. Herbicides such as atrazine, metolachlor/S-metolachlor, Outlook, Warrant, Lexar EZ, Halex GT, Huskie, Permit, and quinclorac are commonly used for preemergence and postemergence weed control in sorghum.

Nitrogen Application

Nitrogen recommendations for sorghum are similar to those for corn, but with lower rates due to the lower yield goal. The required nitrogen rate varies depending on soil texture, typically ranging from 1.0 to 1.3 lbs. of nitrogen per bushel of yield goal. Clay soils generally require higher nitrogen rates compared to sandy soils to achieve similar yields. It is advisable to use split application methods to improve efficiency, particularly when high rainfall poses a risk of nitrogen loss. When applying surface-applied urea, it’s important to consider the higher temperatures and less frequent rainfall during sorghum planting, which increases the risk of volatility losses. Treating surface-applied urea with NBPT before rainfall can help reduce this risk.

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Overcoming Sugarcane Aphid Challenges

Sugarcane aphids can be a deterrent to planting grain sorghum, but with proper management, these challenges can be overcome without impacting yield. Here are some practices to consider:

  1. Plant sugarcane aphid tolerant varieties: While it’s advisable to choose tolerant varieties, non-tolerant varieties can still be successfully managed with proper scouting and management decisions to prevent yield losses.
  2. Early planting: Planting as early as possible (within reason) can help mitigate aphid infestations.
  3. Insecticide seed treatment: Utilizing insecticide seed treatment can provide an additional layer of protection.
  4. Minimize disruptive sprays: Avoid unnecessary sprays unless absolutely necessary.
  5. Maximize coverage: Use appropriate tips and gallons per acre (GPA) to maximize coverage, ensuring thorough protection across the entire canopy.
  6. Frequent scouting: Regular scouting, at least twice a week when the first aphids are found, can help identify infestations early on.
  7. Late-season monitoring: Remain vigilant for potential late-season head colonization.

Remember, with the right strategies and precautions, sugarcane aphids can be effectively managed, allowing for successful grain sorghum production.

For more information and to purchase high-quality sorghum seeds, visit Ames Farm Center.

This article provides expert recommendations for growing grain sorghum, offering valuable insights into planting practices, weed control, optimal conditions, and challenges associated with sugarcane aphids.