Environmental legislation beginning in 1972 has created programs to improve water quality by reducing soil erosion. In general, soil erosion increases as the amount of tillage increases and decreases as amount of plant residue or plant cover increases. In conventional tillage, fields are worked sufficiently to destroy and cover the previous crop residue and to produce a loose, friable seedbed. Weed control is accomplished through cultivation and herbicides. In contrast, conservation tillage is any tillage system in which at least 30% of the soil surface is covered by plant residue after planting. The four major types of conservation tillage are no-till, ridge-till, strip-till, and reduced-till. There has been limited work investigating the possibility of varietal by tillage interactions and the effects of tillage on several agronomic traits in cotton.

A study was undertaken to determine if there is a varietal by tillage interaction and how traits respond to two different tillage treatments. Twenty-two entries from the 1990 Mississippi Cotton Variety Trials were planted under contrasting tillage practices in two adjacent randomized complete block designs in 1990 and 1991. The traits measured were percent stand, seedling dry weight, plant height, open boll number, percent lint, and yield. Results indicated there was a different response to tillage treatment each year. Tillage had a significant effect on each trait measured in one of the two years. A variety by tillage interaction was observed for plant height and percent lint. Under conventional tillage, dry weight, plant height, open boll number, percent lint and yield were higher while percent stand was lower compared to no-till production practices.