RESEARCH PLOT LENGTHS FOR SPINDLE HARVESTED COTTON

Agricultural scientists who conduct field experimentation are confront ed with variability in soil type, soil compaction, and nonuniform inse ct and disease distribution. One way to reduce variability is to use t he appropriate size plots. Plots of cotton, Gossypium hirsutum L., hav ing four rows spaced 1.02 m and harvested plot lengths of 3.04 to 32.2 2 m with four replications were established at Marianna, Calloway silt loam (fine-silty mixed thermic Alfisols) and Clarkdale, Dubbs silt lo am (fine-silty mixed thermic Alfisols), Arkansas in 1978 and 1979 to d etermine the effects of row length and end borders on experimental var iability. Results suggest that cotton research plots harvested with a spindle picker should not be less than 12.16 m in length. End border e ffects were additive but different for different plot lengths, locatio ns, and growing season.