April 24, 2017 Quick Look at Area Soil
Temperatures and Successful Planting of Sorghum, Corn, & Cotton
Planting
season is nearly upon us again, and many good producers are getting very antsy
about getting into the field, especially our sorghum producers who need to get
that crop started and get as much development completed as possible before the
dreaded sugarcane aphid arrives. This
morning I took two soil temperature readings in Southern and Southeastern
Swisher County. The first was 59°F and
in a no-till pivot with heavy wheat stubble cover. The second was at 60⁰F and in conventionally flat
tilled, drip irrigated cotton on cotton ground. This is a pretty good soil temperature for
planting corn or grain sorghum, but is far too cool for cotton. Then there is the consideration of this week’s
forecast with two additional cold fronts due in before the start of May with
night temperatures dipping into the 30’s and 40’s.
The
minimum soil temperature for corn is 56°F (preferably 58°F or with a warmer
week ahead to emerge into) while sorghum requires a 58°F (preferably 60°F or with
a warmer week ahead to emerge into). With
those cooler temperatures in the upcoming forecast I do get a touch apprehensive
about all crops we might have starting in the soil so far, but odd remain that
corn and sorghum should be ok as just as many warm days are predicted as cold.
Cotton
gets off to its best start when planted in a recommended 69°F consistent
temperature soil (roughly 64°F bare minimum with high air temperatures in the
upper 80’s to low 90’s for the following week to continue a steep soil warming
trend). Soil temperature can and does
generally follow air temperatures with some lag time. Higher moisture content in the soil usually
slows the soil’s response to air temperatures while dryer soils respond
quicker. Likewise, soils with heavy
cover will naturally be cooler through the shading of the soil by the cover. The best time to take soil temperature
reading in your fields would be between 7 AM and 10 AM. That early morning period is when the soil
temperature should be at its lowest, guaranteeing that the reading is
accurately the minimum temperature we need to be watching. As I look at the forecast, jumble it up with
research results about cotton getting off to its best start, the cotton should
certainly stay in the barn for a bit longer.
We
will be taking a few more local soil temperature readings next week to get the
best feel for ideal cotton planting conditions.
Good Luck!
Blayne
Reed
