(Field 5F)
Randy Boman, Mark Kelley, Mark Stelter, Doug Nesmith, James P. Bordovsky, Danny Carmichael and John Everitt

Objective: The objective was to determine cotton yield, gin turnout and net value of selected cotton varieties grown under LEPA irrigation in large field plots.

Methodology: Eight varieties, FiberMax 989RR, Stoneville 2454R, All-Tex Atlas RR, Paymaster 2280BG/RR, Paymaster 2344BG/RR, Paymaster 2326RR and Paymaster 2266 RR. were planted in three replications of a randomized complete block design. Varieties were planted in 30-inch rows at a rate of 15 lb seed/acre with a John Deere Max Emerge II vacuum planter. LEPA irrigation applied 11.6 inches during the growing season. Rain fell at 6.1 inches between April and September, 2002. Normal cultural practices were followed and pests were controlled at standard thresholds.

Ginning costs were based on $2.25 per cwt. of bur cotton and $95/ton for seed value. This does not include bagging, ties, and checkoff. Systems costs were determined by variety per acre using manufacturer’s suggested retail prices for seed, and appropriate technology fees for Bollgard and/or Roundup Ready based on the 15 lb/acre seeding rate. The net value was determined by subtracting gin and system costs from the total value.

Results and Discussion: These results indicate that variety selection significantly impacts the final net value/acre (Table 1). The net value among varieties ranged from $625.27/acre (Stoneville 2454 R) to $740.19/acre (Paymaster 2326 RR), a difference of $114.92/acre. Lint turnout ranged from 25.8 % to 29.0%. Lint yields varied from 1337 lb/acre (Stoneville 2454R) to 1517 lb/acre (Paymaster 2266 RR). Pre-harvest losses due to inclement weather were seen with the open boll picker-type variety, FiberMax 989, and the less-storm proof stripper variety, Stoneville 2454R. Additional multi-site and multi-year applied research is needed to evaluate varieties across a series of environments.

Table 1. Harvest results from LEPA irrigated-replicated cotton variety demonstration at Helms, 2002.