Funding toward the purchase of an atomic absorption spectrometers (with flame and graphite furnace facilities). The instruments were purchased from Vanan Australia

last year for a price $109,755.80 and CRDC's contribution has been highly valuable in getting our chemical analytical facilities up to date. The new instruments have been used for the

analyses for a number of common elements including potassium, calcium, magnesium, sodium and several other elements for the research projects involving cotton industry.

The objective of NFF's trade strategy is to achieve a more profitable international trading environment for Australia's farmers. To realise this goal Australia has to expand its international lobbying effort for agricultural trade reform by harnessing the resources of NFF and Australian agribusiness and working with the Australian Government and like-minded industry groups in overseas countries.

The long term production of cotton it the same field often leads to low yields, even with 1:large amounts of nitrogen (N) and phosphorus (P) fertiliser. In the Macquarie Valley of NSW this is often due to soil compaction and poor soil structure (McKenzie et al, 1991). Initially, the problem was corrected by deep ripping the soil, but experiments have shown that drying the soil with crops such as wheat and safflower' can produce similar benefits (Hodgson and Chan, 1984). Rotation crops such as wheat are also used to reduce the incidence of diseases such as Verticillium wilt. In 1992, a survey of cotton growers in the Macquarie, Namoi and Gwydir Valleys was conducted to find out now widely rotations are used, which rotation crops are used, and what problems glowers had encountered with rotations. The survey found that rotation clops were widely used, but the choice of rotation crop was mainly based on convenience eg. it did not need irrigation, it could be sown late, or it was easy to sell. Many growers were interested in using legumes and other crops, but lacked the information to make sound decisions. Can legumes extract as much moisture as cereals, what soil structure benefits do they give, which crop provides the best disease break, are typical of the questions growers had about rotation crops

What are 'survivors'? Are they resistant to Bollgard II?, Control of Helicoverpa larvae in Bollgard II, Helicoverpa thresholds , Insecticide selection for Bollgard II crops.

Helicoverpa spp. remain the key pests of cotton in Australia. The cotton bollworm, H. armigera is becoming resistant to many insecticides. With this increasing resistance as well as environmental concerns with insecticide use, we need to look into viable alternative tools that can be useful in the integrated approach to manage this pest. Semiochemicals or insect behaviour-modifying chemicals fit well in an integrated pest management system due to their specificity and low toxicity. Sex pheromones, have been successfully used in pest monitoring systems and mating disruption techniques for a number of orchard pests. In Egypt, attract-and-kill methods using sex pheromones have successfully contributed to the management of another cotton pest, the pink bollworm, Pectinophora gossypiella (Mafra-Neto & Habib 1996).

Fusarium oxysporum f.sp vasinfectum, (FOV) the causal organism of Fusarium wilt, is a significant threat to the Australian cotton industry. It is therefore essential that various strategies for the development of solutions to this problem are explored. It is hoped that an improved understanding of the genetic factors responsible for the pathogenicity of Fov will uncover novel approaches for disease control. We are implementing a transformation protocol for Fov and developing a project aimed at identifying pathogenicity genes using gene disruption and tagging techniques. We are also generating Fov transformants expressing marker genes to facilitate studies of the interactions of the host and the pathogen.

Precision agriculture (PA) research for cotton in Australia began in 1997 and has followed a clear path aimed at discovering key information for the Industry. The potential benefit of PA management techniques within a particular field over the current "field average" management techniques is directly linked to the amount of spatial variability present, therefore a key question was "how much variability is typical in Australian cotton fields". The second question follows from the first and is "if I have variability in my cotton field, how may I manage it so as to achieve economic and environmental benefits for myself and my community"Γ The answers to these questions have been the goal of two research projects conducted by the University of Sydney with cooperation and funding from the Cotton Research and Development Corporation and the Australian Cotton CRC. The results are detailed in two parts of this paper. The first section "Measuring variability " discusses methods of measuring yield variability and presents results of research into the accuracy of on picker yield monitors. The second section discusses "managing variability" and looks at a method of determining how to better manage nitrogen within a variable field.

Increasing pressure from industry and environmental sectors has begun to force the

Australian cotton industry to rethink its approach to chemical application. This has

led to an increase in ground-based applicators this current year to a record number.

While this is a positive step, it in effect deregulates the industry, moving from a

highly accurate controlled rate applicative technique by a small number of highly

trained operators to a large number of relatively unskilled applicators. As a result the

application of a given chemical in a field and growing area may vary widely with little or no control.

Ground based application of insecticides does allow for banding of costly or limited products, timely application when conditions are more conducive to maximum efficacy, and for optimum target efficiencies. New spraying units offer wide booms, high load capacity, high clearance, air assist nozzles, four wheel drive and speed that combined are able to compete with aerial based application.This project was designed to consider the issues involved in the spraying task and aimed to coordinate efforts with other researchers to achieve the following:

I) Benchmarking of current operational parameters of ground based spray application equipment and techniques. This included the recognition of grower questions and concerns regarding their current practice.

2) Summarising the results from the survey and define the areas of concern that can

be readily addressed. These may include but are riot limited to the effect of speed

on application, use of shields, end of row problems, and nozzle configuration (angle

of incidence, number, position). This will be done in the wind tunnel (if practical) and the field.

3) Develop documentation of project outcomes and report back to the industry. This will include testing protocols, a listing of datum settings for ground based application rigs and recommendations of changes with increasing bush size.

The research had three parts: * Quantify the V AM fungi at depth in the soil * Determine the rate of colonisation of roots of cotton by V AM fungi. and * Develop understanding of the relationship between rate of colonisation and quantity of V AM fungi

Drip irrigation has been advocated as one way of improving both yield and water use efficiency for irrigated cotton. It has even been claimed that drip irrigation can be used to 'crop areas previously considered unsuitable for conventional irrigation methods .... because. ... 'the root zone is maintained at both optimal water and nutrient levels' (Anon,

1988). In this context drip irrigation may be considered a 'non independent' irrigation system where the uniformity of application of water and nutrients by the irrigation system overcomes viability in soil properties. Irrigators have been led to believe that the precision of application of water to the crop from drip irrigation will enable soil and climatic limitations to be to be adequately managed. Field experiment on cotton comparing irrigation treatments were conducted at Warren in the 1999/2000 and 2000/2001 seasons. The control was irrigated at 100% of predicted crop water use (ETcrop), and three treatments that applied 50%, 75% and 125% ETCrop .

Cotton yield was greatest in the 100% treatment followed by the 75% and 125% treatments with lowest yield coming from the 50% treatment for 1999/2000 season. In contrast the 100% and 125% were similar followed by the 75% and 50% for the 2000/2001season. This yield trend, combined with similar soil moisture contents in both the 100% and 125% treatments, suggests that the 100% treatment was supplying adequate water to satisfy crop demand for the 1999/2000 season. Some waterstress was observed in the mid season in 2000/2001 season because of small amounts of underirrigation (0.5 mm Iday).

We found that the irrigation efficiency was limited in both seasons by the large amount of water required to germinate the crop (27% of water applied to the 100% treatment). It is clear that it would be better to use this extra irrigation water to obtain the greater production recorded between the 50% and 100% treatments than to use it only for crop establishment.

We found that gradual development of waterstress (by under-irrigating daily) allowed cotton plants to make osmotic adjustments that allowed the 50% treatment to yield only 17% less than the 100% treatment despite only receiving 31% less water.

Neutron probe readings showed that treatments receiving insufficient water to satisfy crop demand were able to extract water from part of the soilprofile that was not wet by irrigation. Use of this water allowed the 50% and 75% treatments to grow at similar rates to the 100% and 125% treatments for one month in peak growing conditions after the soil was saturated by rain in late December(1999/2000 season) while rain in November of the 2000/2001 season had a similar effect.

Neutron probe readings proved to be sensitive to small changes in applied water and hence are a useful scheduling tool for drip irrigated cotton.