Writer: Steve Byrns, (915) 653-4576, s-byrns@tamu.edu
SAN ANGELO — Ah, spring is in the air and a young man’s thoughts turn to … uh, gardening, and farming.
All across Texas, warmer temperatures are beckoning farmers to their fields and many to their gardens. But it still may be too early to plant many Texas crops.
“Planting too soon in soils that are too cool leads to poor plant performance,” said Dr. Billy Warrick, agronomist with the Texas Agricultural Extension Service in San Angelo.
“All plants have an optimum individual planting temperature that is based on soil temperatures at an 8-inch depth. Gardeners are all too often influenced by a few warm days and a touch of spring fever. Not enough soil warmth at planting gets crops off to a poor start. Pokey plants succumb to disease and insect strikes that healthy plants casually shrug off.”.
Who knows when it’s right to plant? Enter Warrick’s weather station. The odd-looking contraption, resembling a grade schooler’s science fair project, stands perched on a rickety, homemade trailer on Chris Bubenik’s farm. The weather station’s earthen probes are placed right into a row of Bubenik’s field east of San Angelo. The resulting information is phoned directly from the field via a cellular phone to Warrick’s computer back in town. The information is transferred daily to San Angelo’s Texas A&M Agricultural Research and Extension Center web site (sanangelo.tamu.edu) for anyone to access.
Those accessing the Center’s home page get not only average daily soil temperatures, but also daily maximum and minimum air temperatures, average daily rainfall, wind direction, and soon-to-be- added daily evapotransporation rates.
“Each plant species has an optimum soil planting temperature,” said Warrick. “For cotton it’s 60 degrees and for grain sorghum it’s 55 degrees. Our weather station measures soil temperatures every hour at an eight-inch depth. To know when it’s right to plant, find out your crops’ best planting temperatures taken at eight inches at 8 a.m. When the reading hits the optimum planting temperature, start planting.”
After soil temperature, Warrick said, the next most important information to gardeners and farmers is the daily maximum and minimum air temperatures. Like proper soil temperatures, the agronomist said, each crop has a preferred air temperature for optimum growth.
These temperatures are measured in “heat units.” Heat units are determined by subtracting the crops’ minimum temperature requirement from the daily average temperature. The lower the heat unit, the slower the plant’s growth rate. Cloudy, cool weather has much the same effect on crops as does planting too early. Slow growing plants just can’t “outrun” disease and insect problems. For cotton, once the temperature falls below 60 degrees, all growth stops until the weather warms up.
The last bit of information provided by Warrick’s weather station that is of real interest to farmers and gardeners is the average evapotransporation rate. “Evapo (short for evaporation) means moisture loss from the soil’s surface,” said Warrick, “and transportation means water loss from the plant.
The weather station provides information needed to predict the amount of water lost by the plant and soil. Growers with this information are better able to determine their crops’ water needs.
“Rainfall and wind direction are also tracked,” said Warrick, “but most folks already have a pretty good idea of that through their local media outlets. Solar radiation or light intensity’ is also monitored. Solar radiation measures how bright the sun is shining. It’s of little interest to anyone except a scientist, unless you want to know how fast you’ll sunburn while gardening”.
Warrick said Oklahoma has outdistanced Texas, thanks to a legislative weather station system called the Mesonet System. The stations are located grid-fashion every 20 miles across the state. The system is maintained by paying subscribers. Warrick said that due to the number of stations, storms and pressure systems can be very accurately charted as they move across the state.
But, until Texas adopts such a system, farmers and gardeners, at least in West Texas, can surf into San Angelo’s A&M website for the latest weather news.
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