Irrigation scheduling in cotton using the water balance program WATERSCHED has been the subject of an extension development project in Queensland for two years. The project is funded by Cotton Research Council.

The Burdekin region of coastal north Queensland and other areas of tropical Australia provide a significant opportunity for Australian cotton industry stabilisation and contribution to drought proofing. The research that preceded this proposal made significant progress toward the development of a production package for the wet season that incorporates strategies for managing seasonal variability. The focus of this project was to continue and extend upon research work conducted in predecessor projects "The development of sustainable cotton farming systems for coastal north Queensland" and "Completion of Burdekin cotton feasibility study". The wet season in the monsoon tropics is a unique environment for cotton production in Australia. Hence, to reliably achieve this potential requires an agronomic production package tailored to and validated under local conditions rather than the accepted norms of southern production.

A changed political landscape now permits commercial cotton production in the Gulf region of NQ, the Kimberley and Pilbara of WA and the top end of the NT. A key objective this project was to provide expert knowledge to assist cotton investment decisions, validate the Burdekin production package for new wet season growing areas, extend past research to dry season cotton growing areas and support implementation of sustainable and economic production practices for those regions. The knowledge gained from this and predecessor projects was also relevant to cotton regions with climates not typical of the older industry (e.g. CQ and southern NSW) hence this project also supported relevant research and delivery activities in these regions.

Yield responses to increasing amounts of irrigation water have been demonstrated in the past by individual trials. In these trials watering occured at varying deficits of soil moisture below field capacity .

The Cotton Council has been funding our project, for which we intend to identify cotton varieties with efficiency of dry matter production when irrigation is expensive, or relatively inexpensive. The fonner will be achieved by identifying and testing varieties which show little discrimination against l3c assimilation, since it has been shown that this correlates with water-use efficiency. The latter will have both large photosynthetic capacity and large stomatal conductance. We are also investigating the nature of inheritance of water-use efficiency.

This project is part of the Wincott Development program for women in cotton. This is a project that empowers women in the cotton growing community to better manage difficult times that arise with declining water availability and drought. Skills based training enable communities to be more resilient and help manage challenges such as depression within the rural landscape. With the continuing drought, the need for a skills based workshop to develop resilience and leadership skill in women was identified at the Wincott AGM, at the Cotton Conference in August, 2014. 200 women attended and answered a survey of what they thought was needed in the industry. The need for a more skills based workshop in regional areas was listed as a high priority. In the months since then, the drought has hit home even further in most cotton-growing regions. The Wincott committee felt there was an even stronger need to help boost the resilience, build confidence and encourage leadership skills in the regions.

Determination of the petiole nitrate nitrogen concentration (PNN) in the youngest fully expanded leaf (YFEL) of cotton is a useful indicator of plant nitrogen status. In a review of literature Hearn (1981) reported for various phenological stages, l evels of petiole nitrate nitrogen (PNN) adequate for crop growth. These declined from 14000 - 25000 mg kg-1 at first square to 20QO mg kg- 1 at first open boll. He reported a critical level of 2000 mg kg- 1 above which growth would not decline.

At a July 2004 meeting of the CHCG&IA Research and Technical Subcommittee it was resolved that DPI&F research staff develop a strategy to meet the regional R&D needs of the Emerald area, as identified in a discussion paper by Mr. Hamish Millar.

Following discussions with local industry, staff and researchers from the Cotton CRC (Mr. Guy Roth, Drs. Greg constable and Ian Rochester), CSD (Mr. John Marshall) and other QDPI staff, general agreement was reached that a practical way of addressing the regional R&D needs, as identified above, is to begin with a preliminary assessment of cotton phenology and yield response in the form of a one-season pilot planting-time trial.

The Cotton Stewardship Trial(MDBC 12/20),"Developing an environmental

management program for the Australian cotton industry" ("CST") was a

component of the Watermark Environmental Stewardship Program (ESP)

(MDBC 12/16).

The CST has had strong support from (and was jointly funded by) the Cotton

Research & Development Corporation as part of its commitment to the good

management and stewardship of the natural resources utilised in cotton

growing.

The CST had three distinct components:

. It sought to guide the further development of the cotton industrys

existing natural resource management(NRM) program (the BMP Program)

by investigating a range of issues related to the overall form, content and

structure of the BMP Manual and its implementation (including its

relationship with the institutional frameworks that support NRM).

. The finalisation of the last remaining major NRM area to be covered by

the industry's BMP Program, land and water management.

. It provided the on-going support for technical matters raised during the

normal day-to-day activities associated with implementing the BMP

Program.

This Executive Summary provides a brief overview of the trial participants,

followed by a summary listing of the achievements and findings of the trial,

and the resulting recommendations.

The full report provides a detailed listing of the 'best practices

recommended in the BMP Manual, the certification standard that has been

set by the industry for the issues addressed by those practices, discusses

the challenges confronting the industry as it deals with multiple catchment

authorities and catchment plans, discusses the proposed ESS and how it

may benefit the cotton industry and a complete discussion that provides the

background and context to recommendations for the industry to consider as

it continues to nurture the BMP Program from adolescence to maturity.

The cotton industry is on the verge of achieving formal recognition in

Queensland for the BMP Program as an alternative means of complying with

recently introduced regulatory requirements for the management of irrigation

farms. This Project provides a potential platform for the industry to expand

that formal recognition to a broader range of NRM issues, and to its other

major jurisdiction, New South Wales.

Cotton growers commonly apply nitrogen (N) fertilizer at rates of between 100 and 200 kg N/ha, yet the cotton plants seldom recover more than 40% of the applied N, and often much less. What happens to the fertilizer N not recovered in the plants? Some of it remains bound in the soil, and part of this may gradually become available to succeeding crops. Some of it is probably lost to the atmosphere in gaseous forms. Some of it may be leached below the root zone; however, on heavy clay soils, leaching is not generally considered to be an important N loss mechanism. Gaseous N losses. The major gaseous N loss forms are ammonia (NH3), dinitrogen (N2} and nitrous oxide (N20).

Cotton fibre maturity is an extremely important property to spinners and fabric manufacturers because it determines how well fibres will process both from a chemical and a physical perspective. Immature fibres, i.e., those with little or no fibre wall thickening, are associated with the formation of small entanglements called neps, irregularities in processed fibre assemblies including finished yarns, non-uniform dyeing of fabrics and decreased processing efficiency. While knowledge of cotton fibre maturity has always been important with regard to avoiding these problems, there is an increasing need for faster and more accurate measurements.

There are a number of methods for measuring fibre maturity although no one method is able to do so both accurately and with the speed for classing purposes. The methods currently used range from direct measurement of fibre wall thickness from magnified fibre cross-sections to indirect methods that indicate maturity relative to some other fibre parameter.

Direct or reference values of fibre maturity that are used to calibrate faster indirect methods have been obtained by various methods over the last fifty years. Theoretically more accurate, direct values suffer from significant experimental error due to the fine detail involved in preparing fibres for direct measurement and the limited numbers of fibres that can be practically measured. Furthermore, these tests often require the operator to make subjective assessments on the form of the fibre. Indirect methods are favoured by cotton marketers and processors because they provide fast results. However, effects of other fibre features tend to bias the results they give. For example, the Micronaire is the most widely used indirect method for measuring fibre maturity even though it actually measures a composite of fibre fineness and fibre maturity. This means that a fine, mature cotton, which is premium cotton, might give the same reading as coarse, immature cotton. Hindering the development of a fast and accurate indirect method is the absence of an accurate and precise reference method.

In this project CSIRO Textile and Fibre Technology has developed a technology that measures fibre maturity directly and automatically. The advantages over current reference methods are the method’s accuracy, speed and objectivity. Furthermore, the method has a test time equivalent to that of some indirect test methods. The test time for the method at the moment is in the order of 2 minutes, which is similar to test times for other laboratory based fibre maturity tests such as the Uster AFIS PRO and the SDL-Shirley Micromat Cotton Fineness Maturity Tester.