Gilbert Miller’s watermelon field talks to him. Visitors can eavesdrop on the conversation during a July 12 Watermelon and Vegetable Field Day at Clemson’s Edisto Research and Education Center.

The Clemson University Extension area vegetable specialist can turn on the computer in his office at Edisto REC and download a three dimensional picture of soil moisture and nutrients from a series of test plots designed to pin down the causes of hollow heart, a condition which makes melons unmarketable.

“I have four solar-powered sensor stands which collect information on soil conditions and another that collects weather data,” said Miller. “Every two hours they trigger a cell phone call to a server in New Jersey, where EarthTec Solutions puts the data in chart form so I can access it on the Internet.”

The next step is to run a fiber optic line to the field so he can have a direct connection to the Internet, cut out the cell phone and access data in real time. A handful of vegetable producers in South Carolina already use wireless technology to monitor field conditions.

“It helps them control costs and produce higher quality crops,” said Miller. “They save on fertilizer because they apply the right amount of water and don’t wash the nutrients below the root zone.”

Sensors supplied by EarthTec monitor moisture and salinity (nutrient) levels vertically and horizontally at depths of 4, 8, 12, 16 and 20 inches. Miller has four treatment plots, one for each sensor array. One receives the standard Extension recommendations for timing and amounts of water and liquid fertilizer through drip irrigation. In the other three he deliberately shortchanges the watermelons of nutrients, water or a combination of the two, followed by an overdose in order to see which triggers hollow-heart.

The field day on July 12 begins with registration at 9 a.m. at the office complex at Edisto REC. An indoor educational session begins at 9:15. Water and nutrient management will be a major emphasis. Field tours begin at 10 a.m., followed by lunch at noon.

Field tours will give visitors a look at a seedless watermelon variety trial with 25 different varieties, a mini-watermelon trial with 13 varieties, and another trial with more than 50 seedless varieties, eight different pollenizers and two cantaloupe varieties.

Miller’s hollow-heart trial with EarthTec sensors will be on display, along with regular seedless melons and mini-melons planted in late June on white-on-black mulch for September harvest. A late season pumpkin variety trial planted on white-on-black mulch will also be shown.

Visitors will also see melons grafted onto squash and gourd rootstock, a technique being tested for disease resistance.

“We’ll also give visitors a look at organic watermelons on black plastic mulch and straw mulch with Humble Acres Compost,” said Miller.

Edisto REC is on U.S. Highway 78, three miles west of Blackville, S.C., in Barnwell County.

e-mail: tlollis@clemson.edu