The project focussed on phosphorus (P) and potassium (K) status of northern cropping soils.

Stores of P and K have been depleted by crop removal and limited fertiliser application, with depletion most significant in the subsoil. Soil testing strategies are confounded by slowly available mineral reserves with uncertain availability. We have assessed the utility of new soil tests to measure these reserves, quantified their availability to plants and undertaken a regional sampling strategy to identify areas of greatest P and K deficit. Fertiliser application strategies for P and K have been tested and the interactions between these and other nutrients determined in a large field program.

Site-specific irrigation enables the delivery of irrigation water where and when it is required

in the field. Commercially available hardware is available that can adjust the application

from centre pivots and lateral moves; however, wide adoption of these systems is limited

because of a lack of decision-support to determine irrigation application.

The irrigation control framework VARIwise was created to developed, simulate and compare

site-specific irrigation control strategies (McCarthy et al. 2010). This involves: (i) dividing

the field into smaller, controllable sub-areas named ‘cells’; (ii) assigning soil and plant

parameters to each cell; (iii) calibrating the corresponding crop model for each cell; and (iv)

executing a crop production model within in each cell. VARIwise has been used to

determine the optimal data input types and resolution for each control strategy in simulation

(McCarthy et al. 2011; McCarthy et al. 2012).

Two general types of adaptive control strategies have been implemented in VARIwise that

can be applied to irrigation: sensor- and model-based. Sensor-based control strategies use the

difference between a measured and target variable to update the irrigation application, whilst

model-based control strategies determine irrigation application that best achieves the desired

future crop performance as predicted by a calibrated crop production model. Two

implemented sensor-based strategies are Iterative Learning Control (ILC) and Iterative Hill Climbing Control (IHCC).

This project has demonstrated the implementation of adaptive control systems at commercial

cotton cropping sites. The control simulation framework VARIwise has been used for the

simulation and development of irrigation control strategies. The framework potentially

provides site-specific irrigation volumes and timing to be determined in autonomous

irrigation, either for uniform or variable-rate irrigation application.

Field evaluations of the control strategies were conducted on siphon and centre pivot

irrigation systems in Jondaryan, QLD utilising a weather, soil and plant sensors, control

strategies and irrigation control hardware. The siphon and centre pivot irrigation trials

produced yield improvements of 11% and 7% respectively, and water use reductions of 12%

and 4% respectively. Higher water reductions were achieved in surface irrigation systems

than overhead irrigation systems because of the larger volumes of irrigation water applied.

Adoption of these irrigation control systems would provide improved and automated

irrigation management and labour savings to the industry.

An on-the-go plant sensing system was developed to estimate plant density, plant height (for

leaf area index calculation), flower count (for square count calculation) and boll count, as

required to calibrate the industry crop production model OZCOT for the control strategy

operation. This sensing system was stand alone and platforms were developed that enabled

mounting to on-farm vehicles (e.g. moped) and irrigation machines. The centre pivot

irrigation trial indicated that plant data input was preferable to soil data input for model-based

irrigation control strategies.

There is limited control hardware currently commercially available for surface irrigation, and

commercial variable-rate solenoid-based irrigation adjustment hardware is available for

centre pivots and lateral moves. For the purposes of the field evaluations in this project, an

irrigation control hardware system was developed that was independent of the irrigation

system. This was based on adjusting the flow rate using a remotely controllable ball valve

and servomechanism and could be installed in-line with siphons and droppers on irrigation

machines.

Over 90% of the Australian irrigated cotton industry uses surface irrigation. Further

enhancements to the system would entail investigating the spatial resolution of irrigation

application adjustment for both surface and overhead irrigation systems. This would

potentially determine the data requirements of surface irrigation control systems, reduce the

sensors requirement (leading to reduced cost of the system) and increase the practicality and

uptake of the final system. In addition, the control strategies could be extended to consider

fertiliser application in surface irrigation systems, as the efficiency of the fertiliser application

is expected to be related to the efficiency of the irrigation application.

In June 2014, irrigation researchers met in Narrabri for IrriCOMM. This workshop arose from discussion

between CSIRO, CRDC and NSW DPI about irrigation research. The tools that irrigators are using to

manage their irrigations have not changed dramatically over the last 20 years – despite investment in, and

resulting advances to, R&D. The dominant tools being used by irrigators are capacitance based soil

moisture measurement devices, and, more often than not, growers are making irrigation decisions based

on their experience: years of irrigating and knowledge of their irrigation system, field, and soils, and most

appropriate time to irrigate that crop under those specific circumstances.

Researchers have been developing weather and plant based scheduling methods, however, uptake of these

technologies by growers has been limited due to a lack of local readily available evapotranspiration data,

suitable crop coefficients, and the complexity of plant based methods when applying this to large scale

broad-acre cropping systems in a highly variable climate.

The IrriCOM workshop enabled researchers to interact and discuss these issues, gaining a better

understanding of current and future technologies and tools for irrigation management in cotton. It was

found that significant progress has been made with a variety of irrigation technologies and that much of

the research was at a point where it was needing to be extended to the wider cotton community – hence

the 2015 Cotton Irrigation Technology Tour evolved.

The purpose of the 2015 Cotton Irrigation Technology Tour was to showcase the latest irrigation

scheduling and automation field scale irrigation research. New irrigation research is offering

opportunities for growers to improve water use efficiency and yield through more precise

scheduling and application technology.

The tour was comprised of three field days: one at Emerald in Central Queensland; one at Moree in

the Gwydir Valley; and one at Nevertire in the Macquarie Valley.

Latest weather and climate news:Observed rainfall analysis (week ending 18 Jan 2015):Summary of climate indicators: Rainfall and temperature guidance summary:Madden-Julian Oscillation (MJO):Australian Sea Surface Temperatures:Tasman Sea Atmospheric Blocking

In 2003-04, the National Dryland Salinity Program (NDSP) as part of its final synthesis year concentrated on integrating the information and knowledge gained over the past 10 years of nationally co-ordinated research and development into a range of comprehensive products that significantly meet the current needs of salinity managers across Australia. This CD-ROM, an essential part of the NDSP synthesis resources and includes nearly 200 research reports, links to on-line resources, the series of fact sheets - NDSP Tech Notes and the manuals: *Breaking Ground - Key Findings from 10 years of Australia’s National Dryland Salinity Program, *Dryland Salinity and Catchment Management: A Resource Directory and Action Manual for Catchment Managers, and *Dryland Salinity: On-Farm Decsions and Catchment Outcomes - A Guide for Leading Producers and Advisors

Cotton leaf curl disease (CLCuD) is caused by a complex of different begomoviruses and DNA-β satellite molecules. Both the viruses and the satellites are transmitted by the Silverleaf whitefly (SLW). CLCuD is responsible for serious economic losses to cotton production in several areas where it occurs. For example, CLCuD cost the Pakistan industry an estimated US$5 billion between 1992 and 1997. CLCuD represents a serious biosecurity risk to the Australian industry. Early detection of the disease if introduced into Australia is vital to minimise economic losses. This is, through containment to limit disease spread, eradication if feasible or early implementation of management packages if eradication is not feasible.

Begomoviruses are considered one of the major emerging viral threats to crop production worldwide (Mansoor et al. 2006; Varma and Malathi 2003). The number of begomoviruses causing CLCuD has risen from only a few species in 1992 to at least six species, with about 30 different genomic sequence variants within those six species, in 2008 (Fauquet et al. 2008). A similar emergence of different DNA-β satellites has also been observed. The continual succumbing of CLCuD-resistant cotton varieties to the disease in Pakistan and India indicates an ongoing emergence of new virus species and/or DNA-β satellites. Several of these viruses and DNA-beta satellites also infect and cause disease in a range of vegetables and ornamentals, including tomato, chilli, capsicum, cucurbits and hibiscus and as many of these plants species are susceptible to more than one begomvirus, there is opportunity for the emergence of new begomoviruses. This is because multiple virus infections within the one host plant can facilitate a genetic mixing between the different virus species, leading to emergence of new species with altered host ranges and pathogenicity. Given, new begomoviruses or DNA-β satellites, may arise in plant species other than cotton, the viruses of concern to the cotton industry are not just those currently associated with CLCuD, but should also include potential emergence of new species in other plant species. Hence detection and management of CLCuD will involve multiple commodities (eg vegetables and ornamentals) and not be limited to cotton.

Many begomovirus species, several of which potentially cause CLCuD, are present in countries to the immediate north of Australia, such as Indonesia. Establishment of begomoviruses in northern Australia could occur in native vegetation or weeds, including native and endemic Gossypium and Hibiscus species, or in vegetable crops, and once established represent a significant threat for spread to southern cropping areas. Incursions of these viruses could occur through importation of infected plant material, or in virus-laden whiteflies associated with the movement of people, plant material or in tropical cyclones.

Within the last 5 years, Australia had two incursions of whitefly-transmitted viruses, including the begomovirus, Tomato yellow leaf curl virus (TYLCV). The incursion of the two viruses in distinctly different Australian growing regions and their presence at multiple locations demonstrates the existence of multiple entry and spread pathways. Abutilon mosaic virus (AbMV), another begomovirus, has been present in Australia for decades. The ornamental industry sells infected Chinese lantern (Abutilon spp., family Malvaceae) plants as a variegated form due to the symptoms induced by the virus. The presence of this virus in a widely distributed ornamental species highlights a significant risk pathway for virus introduction and spread. Thus, a review of the regulations governing the importation of ornamental species are imported in Australia and what restrictions apply to these imports is paramount to thoroughly analyse the risk for introduction of biosecurity threats such as CLCuD.

The Impact Assessment of CRDC Nutrition Investments 2008-2016 is one of a series of qualitative and quantitative impact assessments of CRDC investments, conduced by Agtrans Research.

CRDC has commissioned the series of impact assessments in important areas of investment, including nutrition, water-use efficiency, Bt technologies and sustainability projects. The purpose of the evaluations is to determine the success of CRDC’s investments against the stated Strategic Plan goals, and to inform future investments.

The Impact Assessment of CRDC Nutrition Investments 2008-2016 found that CRDC’s investment of $11.32 million of grower and Government funds into nine nutrition research projects from 2008-16 delivered major economic benefits to cotton growers. This investment returned a benefit of $61.15 million to growers, or 5.4 to 1.

Cloudy weather impacts, What's coming up, What to watch out for , How to sample whitefly , Abamectin resistance in Two Spotted Mite Increasing.

Expansion will be determined by water availability in combination with markets. Cotton will be considered on its merits like any other crop in the MIA and there will be years where the proportion of cotton will vary compared to other crops such as maize and rice. Like anything the higher the potential for return the higher the risk. Cotton is comparably high in growing cost when

compared to maize and rice. In addition adverse weather conditions particularly at the end of the season could be more costly for cotton in terms of yield and quality compared to maize and rice.

There are inherent risks associated with growing cotton in southern NSW especially south of the Murrumbidgee River. This is why it is essential that there is a capacity for cotton extension to continue in the region. In addition there is a demand for some back to basics research. This season is a prime example with only 1800DD in the southern part of the region yet there are crops that have still yielded over 13bales/ha. Is this high yield attributed to increase day length due to being further south? Cotton is here to stay with many growers investing in new bale picker technology and new ginning operation which will be essential in terms of the areas expansion.

The spring edition of CRDC's magazine, Spotlight, is a special IPM edition. This edition shines the spotlight on early season insect management and the benefits to growers of using integrated pest management principles. The cotton industry has invested many millions of grower and government dollars into pest management, resulting in one of the most robust systems in the world.

Grower Andrew Watson and consultant Rob Weinthal share their experience in controlling pests without sprayed insecticides, which shows what can be achieved when the world class research from industry scientists is enacted. This edition also explores the issue of resistance and the role predators and beneficials play in pest control. Since its formation, CRDC has invested heavily in pest management research – with a focus on created integrated systems that are sustainable and work with the natural environment. CRDC continues to do this through projects researching pest suppressive landscapes, pest ecology, novel soft treatment options and resistance monitoring programs.

Additionally, this edition of Spotlight also features the most recent results of the Australian Cotton Comparative Analysis undertaken in co-operation with Boyce Accountants. This report reiterates that the ‘top 20 percent farmers’ are successful because they operate in some key ways: they pay attention to their operating costs, have consistent marketing strategies, invest in productive labour and reliable machinery, and use sustainable farming techniques. As the report shows, the lowest cost options can often have the biggest impact on the bottom line.