Experiments were initiated in 1984 at the Delta Branch Experiment Station, Stoneville, MS on a mixed Bosket and Beulah very fine sandy loam. Six rotation schemes were chosen to evaluate the utility of rice in improving cotton yield in subsequent years. The six sequences (treatments) chosen were: (1) continuous cotton, (2) continuous rice, (3) 1 year rice:l year cotton, (4) 1 year rice:2 years cotton, (5) 2 years rice:2 years cotton, (6) 1 year rice:3 years cotton. Plots were 60 ft wide and 130 ft long and there were four replicates of the randomized complete block design. Plots planted to cotton were subsoiled to a depth of 14 to 16 inches in the fall previous to the 1984, 1986, and 1987 seasons and in late winter for the 1985 season. Cotton (DES 422) was planted in rows 40 inches wide during the last 2 weeks of April at a seeding rate of 19 pounds per acre. Anhydrous ammonia was applied prior to planting to supply 110 pound of nitrogen per acre and was the only fertilizer used. Rice (cv. Newbonnet) was drill seeded in mid- to late April at a seeding rate of 90 pounds per acre. When necessary, rice was flushed to obtain a stand and flooded in late May or early June when rice was 6 to 8 inches tall. Nitrogen at a rate of 135 pounds per acre was applied as urea prior to flooding. General recommended crop production practices for each crop were utilized in an effort to obtain maximum yields.

Cotton or rice yields were not affected by any rotation scheme examined in any year. Cotton stand counts were not affected after 3 years following rice but were statistically higher in 1987 with treatments 3 and 5. In 1986 penetrometer data revealed an increase in compaction for plots where rice was grown for 2 years prior to cotton as compared to continuous cotton, however, no differences were noticed in 1987. Cotton heights were reduced in 1986 following 2 years of rice this was also noticed in 1987 where cotton had been in a 1:1 rotation with rice for 4 years. When compared to continuous cotton, soil nutrient status was unchanged until 1986 where continuous rice plots were lower in calcium. In 1987, soil test calcium was lower in continuous rice plots and plots with a 1:1 rice-cotton rotation than other plots and was the only soil nutrient adversely affected.