It was demonstrated that varying irrigation deficits, if linked to measures of plant stress, will improve cotton yield and WUE. These benefits if adopted will impact on the 75% of Australia’s irrigated cotton that is grown in a sub-humid climate with significant but variable in-crop rainfall and evaporative demand. When conditions were hot and dry during flowering, as in the 2006/7 season, frequent irrigation of Bollgard II cotton (40mm deficit) increased yield by 17% and WUE by 8% compared to the commonly used deficit (70-80mm) in the lower Namoi that season. In contrast, in 2007/8, where during flowering in-crop rainfall was greater and evaporative demand lower, stretching irrigation during flowering (54 to 78mm deficits) maximised yield, WUE and captured more in-crop rainfall than irrigating at a 40mm deficit. However, irrigation application efficiency tradeoffs are farm specific and need to be measured before adopting small deficits.

Improved scheduling of Bollgard II in water limited situations has been largely achieved with the contribution of the research conducted in this project. The need to avoid water stress late in flowering in Bollgard II was confirmed as yield losses per day of stress were double the conventional variety at the same growth stage. This message has been widely extended over the past three years.

The question of which has the higher WUE, conventional or Bollgard II varieties, has been answered by showing that it depends on the impact that Helicoverpa damage has on crop morphology. In a situations where insect damage was moderate Bollgard II used less water than the conventional variety because the conventional variety grew for longer to compensate for the damage. Where insect damage is minimal there is no difference because the plants are morphologically identical. However the situation where early tipping of the main-stem was the only insect damage to the conventional variety, it had the highest yield and WUE due to the improved canopy structure

The irrigation water requirement of cotton in pressurised systems (e.g. tape) was sensitive to climatic conditions and could be reduced provided the crop factor is varied in response to plant growth and climate. Cotton grew differently in this system compared to furrow irrigation.

OZCOT model enhancement is need if it is to effectively simulate climatic risk in new production regions or changed cropping practices or the simulation of water balances or climate change scenarios.

This project produced data to show: 1) replication is essential for paddock size water balance trials and experiments; 2) a review of plant monitoring methods for early irrigation scheduling is required; 3) new research methodologies developed here will provide indirect benefits to the cotton industry

Water remains a key issue for the cotton industry, with improving water use

efficiency a priority. Relatively water research has focussed on the plant and its interaction with the soil and climate. Currently deficit irrigation and many different row configurations are used in the cotton industry without accurate knowledge of how these irrigation regimes affect root development. Water deficit and irrigation an influence cotton plants root systems: dryland cotton has deeper roots than fully irrigated crops and the timing of first irrigation can be used to encourage good root development. These affects are important in overall plant responses to moisture stress.

This project built on the outcomes of the research project CRC 79 “Water relations of the cotton plant”, continuing to investigate the relationship between soil water and plant stress over a wider range of climates. We investigated plant responses to soil factors through assessment of root exploration between cotton varieties, plant water uptake and the response of cotton to normalised soil moisture deficits (FTSW). This project contributed to knowledge of the effects of soil type, temperature and climate (humidity/evaporative demand/vapour pressure deficit) on cotton plant stress. To accurately detect differences in water use efficiency in cotton varieties, new techniques for measuring differences in root development are required; especially for larger scale screening of breeding lines. Field assessment to detect differences in varietal root development was not successful however glasshouse studies found differences. There is also potential for collaboration in developing molecular techniques / microarray and improving in‐situ field root measurement to identify

cultivar differences. Future work on this subject will be supported by the CBA JV water use efficiency and stress tolerance initiative.

Studies into environmental influences showed that changes in vapour pressure affected the level of stress a plant regardless of the level of soil moisture, highlighting the need for irrigation scheduling to reflect both factors. Current irrigation strategies rely strongly on assessment of soil moisture content by probes or using strategies that have relied on monitoring soil water. However, as growers strive for and obtain higher yields and improved WUE, the interaction between irrigation timing and plant stress becomes more critical. Results from this project,

Steve Yeates and Dirk Richards’s research have indicated an exciting opportunity to refine irrigation scheduling to help reduce the effects of stress during periods of high evaporative demand and particularly save irrigation during periods of low evaporative demand. The new ‘Dynamic Deficits’ project will focus on irrigation strategies to maximise

water use efficiency. It will investigate approaches to irrigation scheduling that take into account plant stress, soil water and climate utilising the knowledge gained in this project about the importance of the impact of vapour pressure on plant stress and water use.

Increases in crop water use efficiency have been found achieved through greater precision in

irrigation scheduling and the use of irrigated crop management strategies such as regulated deficit and

deficit irrigation. However, limitations exist in the use of soil moisture sensors and/or the water

balance approach method of irrigation scheduling. A key limitation with using either of these

approaches for irrigation scheduling is that they do not provide a measure of actual plant water status.

Crop growth and response to irrigation is a function of plant water status and depends on soil water

status, evaporative demand, the rate of water flow through the plant and the corresponding hydraulic

flow resistance between the bulk soil and the appropriate plant tissue. Hence, this project investigated

the potential to use plant based measurements for commercial irrigation scheduling of cotton.

The first year (2005/06) of this project evaluated the potential to use stem diameter sensors for

irrigation scheduling in cotton under a lateral move machine near Leyburn. While the first season

results were encouraging, the second season (2006/07) conducted on furrow irrigation at Nandi across

a range of irrigation schedules and three crop varieties found weaker relationships (i.e the technique

lacks robustness). There was also significant plant to plant variation in sensor responses. The key

recommendation from this work is that stem diameter sensors can be used to identify plant stress

responses associated with irrigation. However, their benefits over traditional irrigation scheduling

technologies are marginal and these sensors will continue to have limited application as an irrigation

scheduling and assessment tool in cotton unless appropriate threshold levels can be identified which

take into account varietal differences and crop conditioning.

During 2006/07, the project evaluated the relationships between hyperspectral canopy reflectance data

and that of plant water status and identified band widths correlated to plant water status when

measured during a normal commercial irrigation cycle. The 2007/08 trial used two sites (Pampas and

Cecil Plains) to evaluate remote methods of plant based sensing (i.e. satellite imagery and groundbased NDVI) and to test the robustness of the relationships between the hyperspectral bandwidth data to changes in crop water status. The active sensor technology (i.e. NDVI) was able to identify varietal differences and varying yield responses under all climatic conditions encountered.

However ground rig speed and sensor distance above the canopy was found to be critical. The passive sensors (i.e. satellite or handheld radiometric) were found to be hampered by poor atmospheric conditions and high variability in localised sunlight intensity. No significant relationships were identified between leaf water potential and either the NDVI or hyperspectral data.

Other outputs include an analysis of historical yield monitor data across five cotton regions to identify

field scale trends in spatial variability. A grower guide to plant based sensing for irrigation

scheduling has also been produced.

In order to maintain its premium in the world cotton market it will be important for Australia

to extend its position as a preferred supplier of high quality fibre. Australian cotton is

currently used by spinners for the production of medium-fine yarns, i.e. in the Ne 30 to 40

count range, although efforts are afoot to extend the spinning range of Australian cotton to

Ne 50 and 60. Currently it is not easy for spinners to accurately estimate key yarn quality

parameters, e.g. yarn evenness and tenacity, in order to estimate the additional value to them

of purchasing cottons with incrementally higher fibre quality.This project has tackled the scientific challenge of predicting the key parameters of interest to

the spinning mill manager from fibre quality measurements. The output of the project is a

user friendly software package that can be used by spinners to predict the effects on their

production of using higher (or lower) quality cotton. The software is potentially an important

tool for marketing high quality Australian cotton fibre. For example, it could be used to

illustrate quantitatively to a spinner the technical benefits of utilising a new variety of finer,

longer cotton, e.g. Sicala 340BRF.Cotton fibre maturity and fineness (linear density) are two important fibre characteristics

affecting cotton yarn quality and spinning performance. CSIRO, in partnership with the

CRDC and the Cotton CRC, has developed two new instruments, namely Cottonscan and

SiroMat for quick and yet accurate measurements of the two fibre properties1. Another

outcome of this project is the incorporation of linear density and maturity measurements into

the Cottonspec prediction model. It is noted their inclusion the Cottonspec models,

particularly of linear density, is solely on the basis of the additional predictive ability they

give to any yarn quality prediction model.Work on this project has occurred in four stages. They have been:

1. Liaison with and collection of industrial spinning data from three leading Chinese cotton

spinning mills,

2. Development of a robust mechanistic and statistical model to predict ring spun yarn

quality,

3. Validation of the model using Australian cotton and industrial spinning mill data and

4. Incorporation of the prediction models and data into software that can be used by mill and

QC managers.

Further validation of the models and software is required before a commercial and release-tomarket

plan can be developed for the Cottonspec program. To this end a new project in

which the current Cottonspec will be tested in five to six overseas (Chinese) mills has

commenced.

There are currently no stand-alone, commercial yarn quality prediction programs available

largely because modelling of yarn quality has largely centred on purely statistical models that

fail in their ability to be applied widely because they overlook the mechanical associations

between fibres in a yarn that affect final yarn quality. Cottonspec overcomes the limitations

associated with statistical modelling by incorporating the rules of yarn mechanics in the

model.

The closest commercial system to the Cottonspec is Cotton Inc.'s Engineered Fibre Selection

(EFS) system. The EFS system is a software package used to manage USDA High Volume

Instrument (HVI) data and allow optimisation of bale inventory in terms of yarn and processquality. The short comings of the EFS system are that it doesn’t predict yarn quality and it does not allow for non-USA cotton to be used. Moreover, EFS considers only HVI-measured

fibre properties. As many mills use a combination of growths and data to control their

laydowns these limitations make the EFS system largely redundant in the day-to-day

operation of large spinning mills.

However, aside from these limitations, the EFS system does provide a tool for spinners to

manage the average quality (as described by HVI) of their lay-downs and in doing so allows

some indirect prediction of yarn quality to be arrived at. The provision and control of the

average fibre properties in bale lay-downs allows spinners to better appreciate the

consequences of using particular quality cotton in their processing. From this perspective

EFS adds value to the use of US cotton by creating the perception that the spinner buying US

cotton is in partnership with the US cotton grower.

The National Program for Sustainable Irrigation and its

predecessors have invested in irrigation research for nearly two

decades covering topics at the field, farm and catchment scales; and

issues ranging from storage and delivery to on-farm application,

environmental risks and recycling. A team was commissioned to

‘harvest’ the information and insights from across that researchand

the resultant reports are now available.

The project focused on aspects of farm hygiene as it relates to crop protection within cotton farming systems, while also providing regional extension support in Central Queensland. Specifically this project addressed volunteer cotton management, farm hygiene practices and disease management.

Key outcomes of project include:

• A farm practices and volunteer cotton survey that confirmed the most successful strategy for controlling volunteer cotton within cotton fields was to utilise 2 or more tactics in unison.

• Data developed during the project from herbicide trials was used to support label changes for 3 herbicides that will enable growers to control large volunteer cotton plants using the weed seeker boom technology.

The products being registered for use on large volunteer cotton are:

1. Comet® (fluroxypyr) applied at 1L/ha twice with a treatment interval of 7 or more days.

2. Comet® applied at 1L/ha and then followed with Nuquat (paraquat) at 3.2L/ha approximately 7 or more days after first application.

3. Comet® at 1L/ha mixed with Amicide 700 (2,4D) at 1L/ha as a single application.

• A variety of communication products that raised awareness of volunteer cotton as a significant threat to biosecurity and crop protection.

The improved understanding of volunteer and ratoon cotton management issues and ability to control volunteer and ratoon cotton in the field will assist in preventing exotic disease incursions, lower the risk of existing disease outbreaks and reduce the opportunity for outbreaks of silverleaf whitefly, aphids and Solenopsis mealybug.

Furthermore technical and extension assistance was provided to Central Queensland projects including Paul Grundy’s (DAQ1401 Strengthening the Central Highlands Cotton Production System) and Richard Sequeira’s (DAQ1204 Management of mirids, stinkbugs and Solenopsis Mealybug) project work as well as other CRDC funded projects which were of regional or industry interest.

Hydrochemical and isotopic results reveal that there are distinct differences in the groundwater chemistry with depth throughout the Lower Namoi Alluvium (LNA). This is due to varying recharge processes, as well as the evolution of the groundwater chemistry through the system. Na-HCO3 - type groundwater is dominant throughout the study area, increasing in concentration with depth. Locally, in areas where the alluvial sediments have a higher proportion of clay, the groundwater is more saline because of evapotranspiration processes and is classified as Na-Cl-type groundwater. Groundwater residence time (an indicator of age) is correlated with distance from the river channel for near surface samples, and with depth due to increased proportional input for the Great Artesian Basin (GAB). Where the groundwater is enriched in Na+, it is most likely the result of mixing between the Na+-rich GAB groundwater and surface-sourced water (river leakage, floodwater recharge, and areal recharge (including irrigation deep drainage)). The weathering of silicate minerals and cation exchange processes in the shallow alluvium with a higher clay content may also contribute to the enrichment of Na+ in the LNA.

High activities of tritium (3H) in the shallow aquifer close to the river corridor highlight the importance of river leakage and flood associated recharge to total aquifer recharge. Modelling the mixing of various water types using a box model mixing approach shows that large floods are the biggest contributor to the renewal of the near-river shallow groundwater. Our calculations also show that minor recharge occurs into the shallow groundwater proximal to Namoi River in years when the region experiences average rainfall. Isotopic data (36Cl/Cl, 14C and 3H) indicate that the residence time of the groundwater is highly dependent on the proportion of groundwater sourced from surface recharge and input from the GAB in each location. The Lower Namoi alluvial groundwater in the study area is a mixture of groundwater of different origin mainly: a) a young component with residence times of < 70 years associated with periodic flooding and; b) groundwater that is potentially hundreds of thousands of years old, mostly derived from outflow from the GAB units.

6

Methane is ubiquitous throughout the alluvium, with the concentration increasing significantly with depth. The CH4 isotope data suggest that the CH4 in the LNA is biologically produced, with varying degrees of microbial oxidation occurring. Our results, coupled with CH4 data collected from formations underlying the GAB (primarily the Hokissons coal seam) by Eastern Star Gas (ESG 2008-2011) suggest that mixing of groundwater in the LNA with water from the GAB has influenced both the occurrence of CH4 in the alluvium (hence the increased concentration and lighter isotopic signature with depth), and the processes acting on the CH4 once it has reached the LNA. Microbial community analyses of the alluvial groundwater show 3 distinct changes in composition with depth. These changes with depth are related to the changing geochemical environment through the vertical profile of the LNA, because of multiple recharge inputs. There are significantly less methanogens in the groundwater than suggested by the CH4 concentration, indicating that in situ production is not the primary source of CH4 to the alluvium.

Comprehensive details on the biogeochemical results from this project are published in:

Iverach C.P; Cendón D.I.; Meredith K.T.; Wilcken K.M.; Hankin S.I.; Andersen M.S.; Kelly B.F.J, (2017) A multi-tracer approach to constraining artesian groundwater discharge into an alluvial aquifer, Hydrology and Earth System Sciences, vol. 21, pp. 5953 - 5969, http://dx.doi.org/10.5194/hess-21-5953-2017

Provide a one page Summary of your research that is not commercial in confidence, and that can be published on the World Wide Web. Explain the main outcomes of the research and provide contact details for more information. It is important that the Executive Summary highlights concisely the key outputs from the project and, when they are adopted, what this will mean to the cotton industry.

SiroMat is an instrument that measures fibre maturity directly and accurately. Its advantage over other test methods is that it measures maturity directly and is able to measure the fibre to- fibre distribution of maturity in a specimen. Moreover the test time is around two minutes, which is comparable with other low volume instrument test times. SiroMat is currently undergoing technical trials with a view to preparing it for commercialisation.

In order for SiroMat to be taken up by the wider industry its utility needs to be realised by the wider research and commercial cotton testing and marketing segments. During a recent meeting with Uster Technologies (USA) interest was expressed in the SiroMat on this basis.

In order to continue to highlight its value SiroMat data will be recorded on samples from a wide number of Australian and international industry sponsored cotton breeding, agronomy and textile projects.

SiroMat is an automated version of the polarized light microscopy technique, which analyzes interference colors transmitted by cotton fibres when they are placed between crossed polars and a first order retardation plate. The percent areas of colors in images of fibre snippets relate directly to fibre maturity. Moreover, because fibres are analyzed on an individual basis a maturity distribution for a sample can also be measured. In this study SiroMat measurements are reported for blends comprising different proportions of cotton fibre picked from plants subjected to differential defoliation timing treatments. The proportion of immature fibres in each sample is correlated with measurements on the same samples of neps per gram made by the AFIS PRO. The motivation behind this study is based on the desire to manage the amount of immature fruit included in a crop, and how this relates to nep generation in the gin and spinning mill.

Fibre maturity is regarded as a central characteristic of cotton fibre through its direct and indirect correlation with physical and chemical properties of commercial and technical importance. SiroMat is an automated version of the polarized light microscopy technique, which analyzes interference colours transmitted by cotton fibres when they are placed between crossed polars and a first order retardation plate. The percent areas of colours in images of fibre snippets relate directly to fibre maturity. Moreover, because fibres are analyzed on an individual basis a maturity distribution for a sample can also be measured. In this study two sub-sets of cotton each with the same average Micronaire but with different fibre maturity values as measured by SiroMat were processed from raw fibre through to dyed finished knit fabric. The objective of the study was to examine the sensitivity of SiroMat average maturity and distribution values in predicting differences in griege yarn and dyed fabric quality. Results of the study demonstrate the relevance of SiroMat test results in terms of predicting fibre maturity and fineness related quality problems and in particular the potential for SiroMat to be used as a tool for managing dye uptake problems at the mill laydown.

Note: this project supported the operation of a fibre quality laboratory at ACRI to service most research projects. Specific details on fibre quality results are listed in those project reports.

This project part funded operation and maintenance of HVI900 and FMT3 cotton fibre testing instruments and associated air conditioning in CSIRO’s fibre testing laboratory at ACRI for the 2006/07 season. The laboratory supports measurements of fibre quality from cotton experiments in CSIRO’s breeding program and research projects by other organisations and projects.

More than 20,000 samples were tested by HVI and 10,000 samples by FMT.

Global cotton production and market dynamics indicate Australia needs a future edge with fibre quality to ensure buyers will want our cotton in preference to our competitors. This means developing varieties, management and processing to ensure we deliver better fibre. There may be opportunities for premium fibre products in future. Thus the CSIRO cotton breeding program raised the emphasis on developing improved fibre varieties to address these needs.

Negative associations between yield and fibre quality present challenges for variety development. We have accurately measured these associations and developed breeding population sizes to ensure the rare combinations of high yield and quality can be identified. Accurate measurement of fibre quality is an important component of that work.

Progress has been good, with improved fibre length achieved in high yielding varieties and breeding material with premium fibre identified.