By Rebekah Ray
Delta Research and Extension Center

STONEVILLE – Two researchers at Mississippi State University’s Delta Research and Extension Center in Stoneville are continuing a centennial study begun in 2004 to examine the long-term effects of rotations on crop yields.

“We plowed the first plots for the study when the Delta station observed its 100th anniversary in 2004, and we refer to it as the Centennial Rotation,” said Wayne Ebelhar, the study’s organizer and a researcher specializing in soil fertility and cotton, corn and soybean production.

The 7.5-acre field is planted with cotton, corn and soybeans in eight-row segments that stretch 215 feet each. The plots are divided into two sections to provide ease in harvesting and to handle any potential problems. Crops are planted in a planned rotation that will repeat every 13th year.

“Cotton, corn and soybean are the Delta’s primary agronomic row crops. For generations, the Delta’s economy was based on cotton, but other row crops are possible now because of technologies and research. The economics of production have shifted,” Ebelhar said.

Technology has led to a rapid expansion in crop production, and biotechnology, hybrid development, irrigation and weed control have revolutionized agricultural production, Ebelhar said.

“The research station’s centennial year was a good time to start the study because of the year’s significance to the university. We are combining conventional practices of agriculture, like irrigation, planting and fertilization, with modern technologies, like biotechnology, global positioning systems, geographic information systems and twin-row planting,” said DREC research associate Davis Clark, who works on the project.

Ebelhar noted advantages to rotation systems.

“In the past five years of the sequence, we confirmed that planting cotton following corn gives higher yields than it does following cotton, which is what we expected,” Ebelhar said.

Twin-row soybean production has shown significant improvement compared to single-row planting. Corn planted behind soybeans did better because of the traditional rotation effect. Adding more nitrogen does not give the same effect as rotation, he said.

Ebelhar was involved in long-term rotation studies in the 1970s while studying at the University of Illinois, and he said he felt Mississippi State could establish itself with Southern crops. Similar long-term rotation studies exist at Auburn and Purdue universities.

DREC researchers hope future Delta agronomists will carry on the tracking of their plots.

“This is our legacy to the agricultural future of Mississippi,” Ebelhar said.