By Kay Ledbetter
Higher prices for grain sorghum due to greater overseas demand from China are creating an opportunity for producers if the crop is properly managed, according to several Texas A&M AgriLife Extension Service experts.
“What’s happening in the sorghum market is a surprise and is exciting for producers,” said Dr. Jourdan Bell, AgriLife Extension agronomist in Amarillo. “The Chinese market has increased prices. As a result, many producers are considering planting sorghum this year to take advantage of the situation.”
Bell said management is key to capitalizing on the situation, and the biggest area of savings can be realized by minimizing production risks and maximizing water use efficiency, or maintaining production with limited water.
When comparing corn and sorghum production, she said, sorghum production is greater when water is limited. In order to optimize sorghum production, irrigation should be managed at critical growth stages.
Grain sorghum prices have producers considering planting more acreage to the crop this year.
Dr. Dana Porter, AgriLife Extension agricultural engineer in Lubbock, offered producers some tips for optimizing limited water.
Management and maintenance are key to realizing the benefits of efficient irrigation methods and best management practices, Porter said. There are some excellent technologies out there for producers to choose from, however, she said site-specific and operation-specific considerations affect suitability of these technologies and best management practices.
“Remember, one size does not fit all,” she said. “The bottom line is to select the appropriate, efficient irrigation tools and practices for your operation based on field layout, water resources, cropping practices, economic feasibility, labor and management capabilities or constraints.”
When planning irrigation strategies, keep in mind peak crop water demand periods, Porter stressed, as well as critical growth stages and total crop water requirements. And don’t forget to consider total water – rainfall and stored soil water, as well as irrigation application – to improve water-use efficiency.
When looking at overall integrated crop management, Porter said to consider and address potential limiting factors, such as crop genetics and nutrient management, as well as water capacity. She also emphasized an integrated pest management program should be included in overall production considerations.
Bell said the “biggest bang” from irrigation in a grain sorghum crop can be achieved by maximizing the by seeds per head, and the most important time to effect this is between the critical growth stages of growing point differentiation and half-bloom. Growing point differentiation is about 30 days past emergence or at the seven to 10 leaf stage.
“Make sure water and nutrients are there from growing point differentiation through bloom,” she said. “Available water and nutrients during these periods offer the greatest potential to increase yield and profit because we are able to optimize seeds per head.”
Bell said managing deficit irrigation at critical growth stages fits well with a split pivot scenario where water is concentrated on a smaller area rather than trying to spread it across an entire field.
Utilizing a managed deficit irrigation strategy whereby irrigation is further concentrated during the critical growth stages would eliminate at least one, if not two, early season irrigation events prior to growing point differentiation, she said,
From half-bloom through reproductive maturity, irrigation is again applied at a deficit rate, Bell said. It is important to realize that a producer must have the well capacity to increase the rate of irrigation during this period.
“You end up applying almost the same amount of irrigation between a standard deficit and a managed deficit strategy, but the concentration of water at the right time will help you see a difference in the seeds per head,” she said.
Bell said other key points to remember are: while irrigation after the hard dough stage is often used to minimize lodging, it does not increase grain production; and producers should not plant the same hybrids and populations under the same irrigation levels, because, again, “one size does not fit all.”
Dr. Calvin Trostle, AgriLife Extension agronomist in Lubbock, added that the two key production considerations producers sometimes make poor decisions related to seeds planted and fertilization.
“The thing about sorghum is there is nothing visual to determine when growing point differentiation is occurring, so a producer just has to go on growing days,” Trostle said. “I say at 33 days from planting you need to make sure you are not limited with nutrients on the crop.”
He said nitrogen fertility and soil testing are important, adding the rule of thumb is to have 2 pounds of nitrogen per 100 pounds of yield goal.
The nitrogen should include both what is already in the soil, determined by a soil test, and what is added through fertilization, Trostle said.
“Do a profile of nitrate testing and credit that fully towards your crop requirements.”
Also, seeds per acre are very important, he said.
“Most limited irrigation (6-8 inches) grain sorghum should target 50,000-55,000 seeds per acre if deep soil moisture is very good, but seeding rates should be reduced by 10,000 seeds per acre if soil moisture is poor,” Trostle said. “Full-irrigation grain sorghum should not increase seeding rates too much from these numbers.”
With dryland sorghum, he said, again adjust to the moisture conditions. Planting 30,000-35,000 seeds per acre is enough when deep soil moisture is good, but reduce rates if deep soil moisture is lacking. These seeding rates are high enough to not limit yield, but low enough to significantly reduce the potential to burn up the crop due to lack of water later during the growing season.
“Less is more when it comes to grain sorghum seeding rates,” Trostle said.