ABSTRACT

The likelihood of a response to starter fertilizer would increase, if the applied nutrients stimulated cotton (Gossypium hirsutum L.) root growth. The purpose of this study was to investigate the effect of ammonium polyphosphate, applied as starter fertilizer, on cotton root growth under conventional tillage and under no-till. Treatments consisted of a check, 1.5 gal. 11-37-0/A applied in-furrow, 7.5 gal. 11-37-0/A applied in a band two inches to the side and below the furrow, and 7.5 gal. 11-37-0/A applied as a surface band. In 1991, significant differences in root length density, RLD, were not detected among the starter treatments under conventional tillage. No-till plots were not sampled in 1991. In 1992, significant differences in RLD also were not detected among the starter fertilizer treatments under either tillage system. Numerical increases in RLD were evident, however, suggesting that further research would be useful. Large coefficients of variation among the root samples were a significant problem.