No-tillage and conventional tillage cotton production in 30-inch and 40-inch rows : a three year study

Effects of tillage practices, row spacings, and application of the growth regulator PIX®̳ mepiquat chloride) on cotton lint yields were evaluated in a three year study conducted in West Tennessee. Average yield difference between no-tillage and conventionally tilled plots was 73 pounds per acre for the 1992 through 1994 season. This significant yield difference was to the advantage of no-tillage production system. Although no-tillage consistently produced higher yield, there was no recognizable year interaction. No yield advantage was found for either 30- or 40-inch row spacings. Average yield difference over the study between row spacings was 3 pounds of lint per acre. However, in any given year, effectiveness of a particular row spacing appeared to be dependent upon the nature of the growing season. Application of PIX®̳ significantly resulted in positive lint yields, the average advantage of using PIX®̳ was 93 pounds of lint per acre. This positive effect of PIX®̳ was influenced by growing season. Further, the positive effect of PIX®̳ application was more pronounced in 40-inch rows than 30-inch row spacing. Maturity of plots was not significantly affected by row spacing on average for the three year study. Tillage, however, did have a significant effect on earliness, with no-tillage plots exhibiting greater maturity. PIX®̳ treated plots also displayed a maturity advantage over untreated plots for the experiment, the magnitude of this advantage of applying the growth regulator PIX®̳ was dependent upon the nature of the growing Season. Plants in 30-inch row spacing measured two inches shorter than plots planted in 40-inch row spacing. Application of the growth regulator PIX®̳ resulted in plants averaging six-inches shorter than plants not treated. Other treatments did not show significant effect on plant height. Canopy closure was significantly affected by row spacing and application of growth regulator PIX®̳ in the 1994 production season. Thirty-inch rows closed canopy 9.3 days earlier than 40-inch row spacing. Average time for closure in PIX®̳ -treated plots was 81.5 days after planting, compared to 78.8 days after planting for untreated plots. No significant effect was found from tillage.