[Grainsoybean] July 12 (And Beyond) Soybean & Grain Sorghum Plantings

— Written By Curtis Fountain and last updated by
To:  Duplin Co. Soybean & Grain Sorghum Interests

From:  Curtis D. Fountain

            Agricultural Extension Agent – Field Crops

Since May 23, the Duplin Co. Airport has received 18.12 inches of rainfall (NC State Climate Office). Approximately 15% of Duplin Co. wheat acreage remains in the field. Many harvested wheat fields have not been planted to soybeans or grain sorghum. Should these fields be planted?

July-planted soybeans and July-planted grain sorghum are risky.  In a May 30, 2013 Soybeans or Sorghum email, Dr. Jim Dunphy (NCSU Extension Soybean Specialist) & Dr. Ron Heiniger (NCSU Extension Corn Specialist) made the following statements. If wheat harvest finishes up relatively late (e.g. into July), does that favor soybeans or sorghum as a double crop to plant behind the wheat? It’s about a toss-up.

Traditionally, NCSU Extension has suggested July 4 as the final soybean planting date. In a June 28, 2013 email, Dr. Dunphy made the following statements. With the prices we’ve had for soybeans the last 3 years, I should probably move that date to July 10 for double-crop soybeans. It’s not that we cannot produce profitable soybeans planted after July 10, it’s that the likelihood of getting the weather necessary to do so keeps getting smaller. A variety planted July 10 will flower and mature about 10 days later than the same variety planted June 10 would, and thus would not have quite as many hours of sunlight to work with.

In 2011, some Duplin County farmers planted grain sorghum after abandoned corn. Necessary grain sorghum nutrients were already present (from the abandoned corn).  One grower planted grain sorghum around July 20. His field soils were highly productive, with good water holding capacity. He averaged 55 bushels/acre of grain sorghum. Other growers who tried the same on less productive, droughty soils were not as fortunate, with some grain sorghum not harvested (little/no yield).

Aside from the above, please consider the following:

Contact your crop insurance provider to discuss what crops you have insurance, what coverage levels will be present at the time of planting, prevented plantings, etc.

What are your input costs for soybeans or grain sorghum? In the May 13 Economic Analysis of Double Cropping Grain Sorghum and Soybeans for 2013 Planting in North Carolina paper prepared by Dr. Nick Piggott (NCSU Extension Agricultural/Resource Economics Specialist), the following variable costs were noted:  $246.51/acre for soybeans and $206.00/acre for grain sorghum. Considering July 12 NCDA Market News North Carolina new crop prices (I selected the highest price), soybeans are $12.48/bushel and grain sorghum is $5.26/bushel (95% of corn price). This translates to 20 bushels/acre of soybeans ($246.51/$12.48) to cover soybean variable costs. This translates to 39 bushels/acre of grain sorghum ($206.00/$5.26) to cover grain sorghum variable costs. My numbers (assumptions) are not important. Your numbers are.

There will a cost to leaving the field fallow. Weeds/grasses will need to be managed.  You certainly do not want to lose the progress made in managing palmer amaranth.  Recommended management would likely translate to leaving remaining wheat straw as is and spraying a broad spectrum herbicide such as Gramoxone (and possibly a residual herbicide). More than 1 herbicide application may be needed prior to frost.

What is the productivity of the soil? The risk will be less for a more productive, good water holding capacity soil. If not planted in mud, the crop should emerge quickly. A good water holding capacity soil will hopefully keep the crop going with little stress and downtime.

Will you be planting in mud? If so, do not plant.

What is your deer pressure or weed situation? High deer pressure favors grain sorghum plantings. High weed pressure might favor grain sorghum plantings. High weed pressure might favor no crop.

The Duplin County average date of 1st fall freeze ranges from November 2-17.

If you decide to plant soybeans, plant a late-maturing variety (Group 7 or Group 8). If you decide to plant grain sorghum, plant a medium-maturing (not late-maturing) variety. For either crop, this is not a time to plant untested, unproven varieties. Narrow rows (7-inch, 15-inch, 21-inch) are recommended versus wide rows (30-inch +).


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