A comparative study of conventional and controlled traffic in irrigated cotton: II. Economic and physiological analysis

Abstract

Expanding the row spacing of cotton can improve water efficiency by enlarging the micro-catchment for water and reducing the number of plants per hectare, as well as facilitating controlled traffic conversion of heavy harvesting machinery. This work assesses the effects of 1.5m row spacing on cotton yield, fibre quality and water use efficiency (WUE) in comparison to the traditional 1.0m row spacing cotton system. A replicated, side-by-side, commercial scale experiment was instigated with a 1.5m row spacing controlled traffic system compared against a 1.0m row spacing standard cotton system. Cotton fibre characteristics, fruiting position and yield were measured along with system water use, in the context of machine traffic. A detailed analysis of soil resource impact is provided in the companion paper. The 1.5m row spacing system was shown to perform better than the 1.0m row spacing system in terms of WUE and machine traffic impact over the two cotton seasons and single wheat season. In the 1.5m system cotton WUE was greater with higher gross margin, even though less cotton yield was harvested. The 1.5m row spacing cotton matured more slowly, led to stronger and longer cotton fibres with overall better fibre quality. Increased gross margin potential of the 1.5m system was shown to entirely offset the cost of controlled traffic conversion within 1 season for a field where heavy machinery had not been used extensively.