Field experiments were conducted in 1988 and 1989 to evaluate the potential for no-till cotton production in North Carolina and to evaluate weed management systems for no-till cotton.

The experimental design was a split-split plot. Main plots were the two tillage systems: no-till or conventional. Subplots were at-planting herbicides and sub-subplots were postemergence-directed herbicide applications. At-planting herbicide treatments consisted of Prowl plus Cotoran (0.75 + 1.5 lb ai/A), Prowl plus Benchmark (0.75 + 0.50 lb ai/A), and Zorial plus Cotoran (1.0 + 1.5 lb ai/A) in 1988. In 1989, Dual plus Cotoran (2.0 + 1.5 lb ai/A) was included. The directed herbicide treatments consisted of either no herbicide or a mixture of Probe plus MSMA (0.5 + 2.0 lb ai/A) applied when the cotton was 4 to 5 inches tall. The conventionally-planted cotton was cultivated 2 or 3 times.

All at-planting treatments except Prowl plus Benchmark provided good to excellent control of goosegrass, Eclipta and spotted spurge. Without the directed treatment, morningglory control was poor with all at-planting herbicides. Regardless of tillage system, morningglory control was excellent with all treatments when followed by the directed treatment. Averaged over at-planting and directed herbicides, cultivation increased morningglory control 12%.

Averaged over locations and herbicide treatments, tillage systems did not affect seed cotton yield. In 1989, when weed populations were heavy, yield differences due to at-planting herbicide treatments were noted. Zorial plus Cotoran and Prowl plus Cotoran were the better treatments. There was also a significant yield response to the postemergence-directed treatment, a 30% increase. In the absence of any herbicide treatment, cotton yield was significantly greater in the conventional plots, emphasizing the impact of cultivation. Neither tillage system nor any of the herbicide programs had an effect on fiber micronaire, length, length uniformity, or strength.