Is there a better way to produce dryland cotton on the Texas Rolling Plains? Researchers at The Texas A&M University System Agricultural Research and Extension Center here are trying new approaches to tillage and cropping systems that may help producers make better use of available rainfall and stabilize dryland cotton yields.

"There are more than 500,000 acres of dryland cotton planted every year on the Rolling Plains. The greatest single yield-limiting factor is soil moisture," said John Sij, Texas Agricultural Experiment Station agronomist based at Vernon. "We are studying ways to bank as much rainfall as we can in the soil, and to stabilize or possibly increase dryland cotton yields and returns."

Rolling Plains farmers typically plant cotton year after year using conventional tillage. This leaves the "clean-tilled" soil bare, which can reduce soil moisture and heighten the risk of soil erosion caused by high winds or intense rainfall events.

"In the '90s, researchers discovered that furrow diking – creating small catch basins for rainfall in each furrow – boosted cotton yields and reduced runoff," Sij said. "This system stored more water than conventional tillage, but it did little to reduce soil crusting or seedling damage from blowing soil. Furrow diking also required different equipment and slowed field operations, so it wasn't widely adopted by producers."

"Other research has shown that using cover crops in conjunction with reduced tillage and a fallow period between crops can boost small grain and oilseed yields in semi-arid climates such as Western Kansas and Eastern Colorado," Sij said. "We are curious to see if we can incorporate a cover crop with reduced tillage and a fallow period and get good results with dryland cotton."

Cotton Incorporated's Texas State Support Committee funded this three-year research study with producers' check-off dollars. Todd Baughman, Texas Cooperative Extension agronomist, David Bordovsky, Experiment Station research scientist, and research associate Jason Ott are helping Sij conduct this study at the center's Chillicothe farm.

"We are using SureGrow 215 Roundup Ready, Bollgard cotton and Cutter wheat," Sij said. "We used conventional, clean tillage to prepare the ground for the first cotton crop.

"We fertilized according to soil test recommendations and seeded cotton in May 2003, at three seeds per foot of row. We also applied herbicides to keep the crop weed free."

May and June rainfall got the first cotton crop up and growing. Soil moisture carried it through to harvest in October. After cotton harvest, the researchers seeded wheat into the cotton stalks in December 2003 at a rate of 60 pounds per acre. September and October rains provided the moisture necessary to germinate and establish their wheat crop.

"We switched to no-till with the wheat crop. After seeding the wheat with a no-till drill, we applied fertilizer," Sij said. "We reduced our nitrogen rate because there was some residual soil nitrogen from the cotton crop. That may have cost us a little bit of wheat yield, but our tillage cost to establish the wheat was much lower than with conventional tillage."

Most conventional dryland cotton on the Rolling Plains produces 250 to 350 pounds of lint per acre in a normal rainfall year. The researchers' first cotton crop in this study yielded 300 to 350 pounds of lint per acre. Their subsequent no-till wheat crop fared just as well.

"A normal yield for continuous dryland wheat in this area is 30-plus bushels per acre, somewhere in the mid-30 bushel range," Sij said. "Our yield goal for our wheat was 30 to 40 bushels. It actually produced 41 bushels per acre."

After the wheat crop was harvested in June 2004, the researchers began "farming" rainfall with the wheat stubble and by making chemical treatments to keep the land fallow and clean of thirsty weeds.

"Rather than planting wheat and double cropping with cotton, we plant cotton and double crop with wheat. We include summer and winter fallow periods to capture and bank rainfall in the soil," Sij said. "We have successfully produced two different crops with this system.

"Our first cotton crop and the subsequent wheat crop did well. A 10-month fallow period follows the wheat crop. We treat for weeds during the fallow period even though the wheat stubble helps suppress weeds. We know the stubble will catch any rainfall we receive and help conserve soil moisture for the next cotton crop."

This stored soil moisture should help stabilize cotton yields at higher levels during droughty summers, the agronomist said.

"We keep tabs on soil moisture by taking moisture readings with a neutron probe. We have two-inch PVC tubes set up at regular intervals in our plots. We drop a probe into each tube every other week to get soil moisture readings from as deep as five feet."

The researchers will plant their second cotton crop into the remaining wheat stubble next May or June. Banked soil moisture from the fallow period, plus seasonal rains in the May through October growing season may help that crop yield more than conventional dryland cotton, Sij said.

"How our third crop fares will depend on banked soil moisture. Everything hinges on soil moisture," Sij said. "Cotton is an excellent indicator of deep soil moisture.

"If our second crop yields well – better than our first and this area's long-term average – we may have found an alternate cropping system for the Rolling Plains. One that will help producers reduce erosion, capture and bank more rainfall as soil moisture, and increase yields and returns with fewer input costs."