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.

A series of trials for evaluating new cotton strains and cultivars in Queensland was conducted in collaboration with the CSIRO cotton breeding programs based at Narrabri.

Queensland trials in the Australian Cotton Cultivar Trial series were grown at Brookstead on the Darling Downs and at Moura and Emerald in central Queensland.

Strain Trials to evaluate preliminary and advanced breeding lines were grown at Brookstead (Short Season lines) and Moura and Emerald (Full Season lines).

“Hot area – material” was tested in trials at Emerald while “Ingard” lines were tested in trials at Emerald and Brookstead.

Once again Dryland cotton variety trials were attempted on the Darling Downs (Dalby) with the hope that the current drought conditions did not prevail.

The outcome of these trials was the commercial release of new cotton varieties that have higher yields and improved fibre qualities, especially fibre strength.

The inclusion of Queensland sites for early generation testing improves the efficiency of the selection process and assists the CSIRO breeders identify high yielding cultivars with high fibre quality and other desirable attributes suited to “local conditions”

The testing of vast numbers of cotton breeding lines, from the CSIRO program, throughout the cotton growing regions of Queensland, has resulted in the eventual release of new/improved commercial cotton varieties. These (especially INGARD varieties) require less chemical spraying during the growing season (sustainability of natural resources – Environmental) and at end of season produce higher yields (profitability for grower – Economic) and better quality cotton (competitive markets and higher prices - Economic). This then has a flow-on effect on people and communities whether they are in the cotton industry directly or indirectly (Social).

The commonly used Micronaire value for cotton is related to both fibre fineness and maturity. There is a need for a new measurement technique to separate these. This is of particular importance to the Australian industry where varieties of fine, mature cotton have the potential to be wrongfully discounted commercially by misinterpreting a low Micronaire value as indicating immaturity in a coarser fibre.

CRDC is currently funding research at CSIRO Textile and Fibre Technology aimed at developing techniques to measure fibre fineness and maturity to overcome this deficiency in the Micronaire measurement.

One difficulty with research in this area is that there are no internationally recognised standard cotton samples that can be used for checking the accuracy of new measurement approaches or for that matter for checking the calibration and accuracy of existing instrumentation.

Researchers in the US are tackling this problem by coordinating the development of a standardised set of cotton samples specifically for this purpose. Once this work is completed, the cottons in this set will each have well characterised values of both fibre fineness and maturity and the set will cover a wide commercial range in these parameter values. This set will then be of extensive value to the cotton community.

In order to accurately determine the correct fineness and maturity of each sample bale, samples will be measured by a variety of techniques and in a variety of laboratories and CSIRO Textile and Fibre Technology (TFT) in Geelong, were invited to participate in these trials as an independent measurement test laboratory.

During this project CSIRO became proficient in the specific techniques of sample preparation and developed software for the analysis of the images of fibre cross sections. After detailed validation trials of the CSIRO techniques, measurements were undertaken on a set of seven different cottons. In total more than 30,000 individual fibre cross-sections were imaged and analysed. The results from these trials have been satisfactorily correlated with the data from another participating laboratory. This is a major step towards establishing accepted values for these reference cottons.

This symposium was the first conference held specifically for biological control of arthropods and follows the successful model of four-yearly symposia for biological control of weeds. Attendance was limited to 250 people with only a single session to maximise participation and exchange of information. It was an excellent opportunity to hear the latest research developments in several relevant areas, including the use of molecular methods to estimate predation, the use of alternative habitats to conserve natural enemies and the effects of Bt crops on beneficial insects. My current project investigates the ecology of key predators and their impact on Helicoverpa populations. At present an ELISA system is being tested and this system will be used to quantify predation on Helicoverpa armigera in cotton. However this area of research is changing rapidly with new techniques under constant evaluation and development.

This project examined the costs and benefits of defoliation strategies used in the defoliation of high input irrigated cotton crops. The project comprised of a field trial and a survey of irrigated cotton enterprises.

The field trial evaluated defoliation efficacy through ground rig and aerial application and measured crop damage from ground rig application.

Similar defoliation efficacy was achieved using ground rig and aerial defoliation for the first pass in this project.

Crop damage sustained through ground rig application must be considered in calculating the costs and benefits of application method. Based on a price of $12/ha for ground rig application and $16/ha for aerial application, cost per application by ground rig is lower than aerial application when damage is taken into account.

The benefits of ground rig application are lower drift risk and smaller down wind buffer zones than occur with aerial application. Area to be defoliated is a limiting factor for ground rig application. Arial application is an important method of defoliant application in large scale enterprises.

Efficiency drivers for both ground and aerial application were identified. These were boom width and speed of travel for ground rig application and volume for aerial application

The survey identified current defoliation practices used and the decision making drivers behind the practices used. From the current practices used by growers, a set of best practices for defoliation was identified. These practices achieve good defoliation efficacy while minimising spray drift risk and effects on the environment.

Best practices currently used by growers were identified as:

• Canopy management with plant growth regulator to enhance evenness and defoliant penetration.

• Sprayer set up which maintains efficacy while minimising environmental impact by using a coarser spray quality for example Turbo TwinJet®twinjet nozzles (standard or the air inducted version) for ground rigs and CP nozzles for aircraft.

• Droplet size – using bigger droplets (medium to coarse spray qualities) which maintain efficacy but minimise drift risk and the down wind no spray zone distances required.

• Using ground rigs to defoliate next to sensitive areas.

• Using a pesticide application management plan to manage spray drift risk in accordance with mandatory down wind no spray zones in accordance with new label guidelines.

• Defoliating as much are as possible when wind conditions are appropriate.

• Defoliating the crop in the least number of passes which reduces the drift risk and potential impact on the environment.

Decision making drivers for defoliation were identified

Timing of the first pass is primarily driven by crop maturity (top boll maturity and openness) with the timing of subsequent passes is more influenced by weather forecast (rain or a cold snap) and picking schedule

Application method (ground or air) is predominantly decided on by the area to be defoliated. Canopy density, weather forecast and soil moisture also play a part in the decision making process.

Sprayer setup is primarily driven by canopy density, label requirements and downwind buffer zones

Canopy density is the main decider for application volume, with products used and weather conditions as the other contributing factors.

Waterbirds have been observed on constructed water storages of the irrigated cotton landscapes in northern NSW for decades and yet there have been few studies to quantify the importance of these structures. Additional research was needed to update and compare knowledge, to develop an on-going monitoring framework, and benchmark the current value of these storages to the conservation of waterbirds.

The study was conducted from September 2014 to June 2015 and involved a reconnaissance trip and six field surveys. Fifty water storages were surveyed, 30 in the Gwydir and 20 in the Namoi. The storages were mostly at low levels due to seasonal conditions.

A total of 31,006 waterbirds of 55 species were counted on the water storages. This is a higher number of species than recorded in previous studies, although additional species were represented by a low number of individuals. Ducks and coots were the most abundant waterbirds observed, as they were in previous studies. Threatened species observed included Brolga, Magpie Goose and Freckled Duck. Migratory species observed included Sharp-tailed Sandpiper, Black-tailed Godwit (which is also threatened), Latham's Snipe, Common Greenshank, Marsh Sandpiper and Red-necked Stint.

Counts of waterbirds per survey unit (no. storages x no. surveys) in the current study and previous studies were between 80 and 120 waterbirds, highest in the current study and lowest in Namoi 2008 study, a result attributable to a smaller sample size in the 2008 study. Counts were similar between the Gwydir studies, 93 waterbirds per survey unit in the current study compared to 97 in the 2001 study.

Observations of nesting were few in the current study, much fewer than in the 2001 study, attributable to low and inconsistent water levels during the current study. Clearing of dead trees from some storages has removed the nesting habitat of waterbird species that might otherwise breed in those storages, diminishing overall breeding opportunities.

In 2001 it was estimated that on-farm water storages represented 45% of the wetland area of the Lower Gwydir Valley but supported 1 to 5% of the Valley’s waterbirds. The results from the current study do not challenge that estimate.

The main value of the irrigation storages to the conservation of waterbirds appears to be as opportunistic foraging habitat. Irrigation farming has created an extension of this habitat in the landscape, although storages appear to support fewer species, individuals and breeding of waterbirds than do natural wetlands. Numbers of individuals and species of waterbirds are highest in storages that are shaped and managed such that a range of habitats (e.g. shallow/deep, vegetated/bare) are available simultaneously.

Future research should include: extending the scope of study into other cotton areas; integrating studies of natural and artificial wetlands; detailed studies of local waterbird ecology such as movement, habitat use and food webs, and; developing pro-active management strategies such as using environmental water in storages under stewardship arrangements and for environmental off-sets.