Is Row Spacing Important for Soybean Production?
The answer to the title question is “it depends”. It is likely that, regardless of the row spacing that is used, final stand is more important, and the more uniform the stand, the better. As stated in a FarmProgress article titled “Do wide soybean rows make sense?” by Allison Lund, “final stand matters” no matter what row width is used.
From the above article, pertinent points to consider about choice of soybean row spacing follow.
• 15-in.-wide rows are popular, but that likely is a result of herbicides being used for total weed control rather than a universal/economical large yield advantage over wider rows.
• Some producers plant soybeans in 30-in.-wide rows so that the same planter can be used to plant both soybeans and corn. This should cut equipment costs. Also, 30-in.-wide rows allow for equipment traffic in a growing crop without the inevitable running over growing soybean plants that are being grown in narrow [e.g. 15 in.] rows.
• Planting in ultra-narrow rows [e.g. 7.5 in.] with a grain drill will likely result in earlier canopy closure that can mitigate weed pressure and may utilize less expensive equipment, but drills are not noted for planting at a uniform density or depth. Thus a higher seeding rate is likely necessary when planting soybeans with a drill, and this will increase planting cost.
• In the end, the proper soybean row spacing is about what fits each producer, and will depend on soil type, equipment availability, available labor, and the acreage to be planted. Each individual producer must do the math to determine what soybean row spacing best fits their operation.
Interestingly, entrants with the top yields in the recently compiled results from the MSPB-sponsored Miss. Soybean Yield Challenge/Contest used several different row width configurations to achieve their top yields. A summary of those results follow.
Delta Irrigated. Top yields ranged from the mid-80's to mid-90's bu/acre. Row spacing used for these yields ranged from 30 in. to 38-40 in. twin rows, with all but one of the top yields being achieved with twin rows [the outside rows in a twin row setup are usually 30-32 in. apart].
Delta Dryland. Top yields ranged from the low to high 60's bu/acre, and were achieved from plantings in either 38-in.-wide rows or 38-in. twin rows.
Non-Delta Irrigated. Top yields ranged from the low to high 90's bu/acre. Three of the four top yields were obtained from soybeans planted in 30-in.-wide rows. The highest yield was obtained from soybeans planted in rows that were 15 in. wide.
Non-Delta Dryland. Top yields ranged from the low to high 80's bu/acre, and these yields were obtained from soybeans grown in rows that were 30 in. wide.
Overall Results. Using these yield results as an indicator, it appears that a row width of 30 in. will provide the greatest soybean yields in both dryland and irrigated environments in Miss. As stated above, individual producers must do the math to determine what row spacing best suits their operation.
For a detailed discussion of things to consider when choosing a row spacing for soybeans, click here to access a Row Spacing White Paper on this website. Click here to access a White Paper that provides a detailed discussion of things to consider when choosing a seeding rate for soybeans.
Compiled by Larry G. Heatherly, Apr. 2024, larryh91746@gmail.com