Situated in the Dry Tropics, the Burdekin is Australia’s largest tropical irrigation area and is home to a vibrant range of agricultural industries. Cotton has a potentially excellent fit in the Burdekin sugarcane farming system as a summer fallow rotation crop in each field every 4-5 years (currently, an average of 15,000 ha is bare-fallowed annually within the region). In this system cotton offers the opportunity to use a tap-rooted, herbicide tolerant crop rotation option that allows targeting of problem weeds such as nutgrass. The incidence of nematodes and soil pathogens that prefer monocot hosts may also be reduced. Alternatively, cotton can be rotated with maize or grain legumes as part of a continuous double cropping program. This has the potential to be highly profitable although it requires a high degree of management skill as this system is intensive with short turnaround times at the end of each crop cycle.

New generation transgenic varieties enable the production of cotton in a tropical environment with fewer pesticides. Herbicide tolerant traits such as Roundup Ready Flex® allow weeds to be controlled post-planting with glyphosate, which is more environmentally benign than traditional weed management strategies that rely on soil applied residual herbicides and inter-row cultivation. Bollgard II® varieties have significantly reduced the need for insecticides on cotton and provide a foundation on which more sustainable Integrated Pest Management (IPM) practices can be applied.

Whilst cotton production would appear to be an intrinsically attractive cropping option, the Burdekin has a number of climate-related challenges that set it apart from all other Australian cotton production regions. Therefore this project focused on determining whether or not cotton could be successfully grown in the Burdekin climate and developed a set of unique production practices that better enable growers to manage and offset climate risks.

The key outcome from this project was a demonstration that high quality, high yielding cotton can be successfully grown in the Burdekin climate on course textured soils and that during wetter than average seasons (the key climatic impediment) acceptable yields can be grown provided that locally tailored agronomic tactics are used. Excellent fibre quality has been a consistent characteristic of cotton produced in the Burdekin since commercial trials commenced in 2008.

Cloudy weather in autumn (typically associated with later than normal monsoon weather systems) can limit yield potential. The frequency of these events is difficult to predict as reliable weather records only span a 60 year period, however the short term data suggest that these patterns occur in approximately 30% of seasons. Despite this climatic constraint the agronomic practices developed (varietal selection, optimal sowing window, sowing rates, canopy and nitrogen management strategies) can be used to produce acceptable yields of 7-8.5 bales/ha in these constrained seasons which is sufficient to recoup costs and generate modest returns for growers.

For drier than average autumns that occur more than 50% of the time, the research demonstrated that very high yields (>8.5bales/ha) of cotton can be grown with locally tailored agronomic practices that account for the earlier summer monsoon.

This project has shown the potential for cotton production in the region developed a range of tactics that can be deployed to minimise the impact of cloudy wet weather. These agronomic tactics have been published in a new book - NORpak - Cotton production and management guidelines for the Burdekin and NQ coastal dry tropics. This publication has been specifically targeted for local sugarcane producers who may stand to benefit by including cotton rotation crops into their current largely mono-culture production systems. This publication is available at http://www.cottoncrc.org.au/industry/Publications/Northern_Production.