Impact of Cover Crops and Nitrogen on Cotton Fiber Cellulose and Quality Traits

Fiber quality varies depending on the fruit position of the cotton plant. Nitrogen (N) availability can alter fruiting dynamics and, consequently, fiber quality. The current study evaluated the effect of cover crops and N availability on cellulose content and fiber quality in different plant positions. The experiment was carried out in Presidente Bernardes, Sao Paulo, Brazil. Experiment design was a split-plot in completely randomized block design with five replicates. Cover crops were allocated: Fallow (F), Velvet bean (VB), Ruzigrass (Urochloa ruziziensis) (R), Inoculated ruzigrass (IR) (Azospirillum), Ruzigrass + velvet bean (R+VB) and Inoculated ruzigrass + velvet bean (IR+VB); and N rates (80 and 120 kg ha(-1)) in the sub-plots. Cellulose content in the lower, middle, and upper third of the plants were evaluated at 15 and 30 days after anthesis (DAA) and at harvest. At 15 and 30 DAA, the cellulose content was higher in the lower third in most treatments, except in the treatment with ruzigrass (120 N), which was higher in the upper third. Fibers with higher quality and final cellulose content are in the lower parts of the plant, and IR+VB improved fiber quality by providing applications with lower rates of N.