Posted on Oct 19, 2018
By Brent Bean, Ph.D., Sorghum Checkoff Agronomist
With summer crops harvested and wheat planted, growers’ thoughts turn to the selection of different crops they should plant for the 2019 growing season. Growers should consider adding grain sorghum to the mix – and for good reasons.
Inexpensive to Grow
Grain sorghum is a drought-tolerant crop that is inexpensive to grow compared to other crops. Based on 2018 Crop Enterprise Budgets from the University of Arkansas, the net operating expenses for dryland sorghum are $64 less than soybeans, $184 less than corn or peanuts and $240 less than cotton.
Unfortunately, increased management costs for sugarcane aphid control have played a role in the decrease in grain sorghum acreage grown since 2015, particularly in the mid-South, Delta and mid-Atlantic regions. However, the industry has come a long way in identifying hybrids with aphid tolerance and developing management strategies for control, making sugarcane aphids much less of an issue in the last two years than in 2015 and 2016. Nature also has its unique way of dealing with new pests over time as beneficial insects adjust to a new food source.
Yield Advantages When Grown in Rotation
Grain sorghum can produce yield advantages for soybeans, cotton and even corn when used in rotation. Research consistently has shown yield advantages for cotton and soybeans when following sorghum, and recent research with corn revealed positive results.
In rotation with cotton, sorghum breaks up soil disease cycles such as verticillium wilt, and the crop residue increases soil moisture storage and protects emerging cotton from wind damage. In a 2017 trial conducted by researchers at Texas A&M University, cotton following sorghum produced a 26 percent higher yield than continuous cotton.
In a multiyear trial conducted near Stoneville, Mississippi, by the U.S. Department of Agriculture-Agriculture Research Service, soybean yield increased 8.3 bushels per acre following sorghum compared to continuous soybeans. Higher soybean yield following sorghum has been attributed to one or more of the following: increased soil fertility, improved soil physical properties, better weed control, and reduced diseases, nematodes and insect pests. Sorghum is a nonhost to soybean cyst, root-knot and reniform nematodes.
A surprise to most growers, grain sorghum also appears to benefit corn yield when following sorghum. A five-year trial from Kansas State University recently demonstrated an 8.4 percent increase in corn yield following sorghum compared to continuous corn.
When used in a rotation with soybeans or cotton, growers should consider the herbicides used on these crops and read the herbicide labels to determine if they pose any risk to sorghum. Always carefully read and follow all label instructions. Staple LX/Pyrimax and Envoke are the two most often used herbicides in cotton that can cause injury to sorghum the following year. Soybean herbicides are seldom a problem to sorghum the following year, but growers should check the labels when using Pursuit, Typhoon/Flexstar, Sonic/Python or Canopy.