Row configuration as a tool for managing rain-fed cotton systems: review and simulation analysis

Rain-fed cotton production can be a significant proportion (average 17%) of the Australian Cotton Industry. One of the management techniques that rain-fed cotton growers have is to modify row configuration. Configurations that have entire rows missing from the sowing configuration are often referred to as 'skip row'. Skip configurations are used to: increase the amount of soil water available for the crop, which can influence the potential lint yield; reduce the level of variability or risk associated with production; enhance fibre quality; and reduce input costs. Choosing the correct row configuration for a particular environment involves many, often complex, considerations. This paper presents an examination of how rain-fed cotton production in Australia is influenced by row configuration with different management and environmental factors. Data collated from field experiments and the cotton crop simulation model OZCOT, were used to explore the impact of agronomic decisions on potential lint yield and fibre quality and consequent economic benefit. Some key findings were: (i) soil water available at sowing did not increase the advantage of skip row relative to solid configurations; (ii) reduced row spacing ( 75 cm) did not alter lint yield significantly in skip row crops; (iii) skip row, rain-fed crops show reasonable plasticity in terms of optimum plant spacing within the row (simular to irrigated cotton); (iv) sowing time of rain-fed crops would appear to differ between solid and skip row arrangements; (v) skip row configurations markedly reduce the risk of price discounts due to short fibre or low micronaire and this should be carefully considered in the choice of row configuration; and ( vi) skip configurations can also provide some savings in variable costs. In situations where rain-fed cotton sown in solid row configurations is subject to water stress that may affect lint yield or fibre quality, skip row configurations would be a preferential alternative to reduce risk of financial loss.