Polymeria takeall, or Peak Downs curse, is a deep rooted, rhizomatous, perennial weed which spreads from seeds and rhizomes. It tolerates cultivation and can be spread by cultivation. In-crop it can best be managed with repeated, heavy applications of glyphosate on actively growing polymeria, applied through well constructed shields. Good crop agronomy is also important, resulting in competitive, strong cotton. Polymeria in fallow can be controlled with glyphosate on actively growing patches and with Starane in autumn. Heavy rates of Arsenal may be useful on waste areas.

Silverleaf Whitefly (SLW) is a major pest

due to its ability to contaminate cotton

lint with honeydew. Management of SLW requires a year round Integrated Pest Management (IPM) approach as SLW are highly mobile, can quickly build resistance to many insecticides and numbers can rapidly expand especially if natural enemies are reduced by insecticides. This document provides recommendations for effective monitoring and best management of SLW in Australian cotton.

This project is investigating water bird communities on cotton storages in the Gwydir and Namoi Valleys. This project will provide information on the use of water storages by water bird populations with links to habitat and management.

Salinity has increasingly been identified as one of the most serious environmental issues facing Australia (PMSEIC, 1998; MDBC, 1999). Although there has been an increase in awareness of salinity throughout the community there is still a perception that salinity is a soil related issue and that the major impact is on the agricultural sector. These perceptions and limited understanding of the processes contributing to salinity have led to many in the cotton industry dismissing salinity as a threat without considering the fundamental drivers of salinity and their relevance to cotton producing regions. In this paper, I will attempt to provide a brief "report card" on the most significant salinity related issues for each of the major cotton growing districts. In some areas, salinity problems can be observed right now, although in many cases this paper will highlight the presence of significant "risk" factors for the future. The delineation of key risk factors for each region allows the industry to be pro-active in its management of salinity problems and examine management alternatives, which will minimise the impact of salinity on both agricultural productivity and water quality.

Balanced fertilisation of major plant nutrients, nitrogen, phosphorus and potassium is a prerequisite for optimum growth and development of any crop including cotton. Interaction between nitrogen and phosphorus has been reported widely. For example, increasing level of N might influence the efficiency and uptake of P, and vice-versa. Similarly, optimum potassium nutrition for boll retention and boll loading is critical for cotton. Although Hearn (1975) and S. Yeats (1997; personal communication) conducted field experiments for optimising N levels, there has been no work involving all the three major nutrients for cotton production in the Ord. Our work reports results from a preliminary study conducted in 1999 on yield and quality of cotton in response to N, P and K fertilisation

In the Namoi valley a pilot project has trialled exciting new ways to engage growers and their families in managing natural vegetation on their farms under best practise. Engagement has focused on families using existing social networks and has proven to be very successful.

In the irrigated cotton-growing areas of south eastern Australia, there is an increasing awareness for the need for land resource information and its importance for environmental management. This is particularly the case at the field scale where soil management is highly desirable. Acquisition of soil information at this level is labour intensive and time consuming, however. A major problem is determining where samples should be taken. What is required is a relatively cheap and efficient technique, based on remotely sensed data, which can be used as a surrogate for soil survey and therefore assist with the selection of suitable sampling sites to account for the various soil types and spatial variability of soil properties.

Can knowledge of climatic conditions and associated rainfall variability at time scales of several seasons to decades be used to improve cropping systems managementΓ This is a question at the core of this GRDC/CRDC funded research project. There have been many examples where farming practices in Australia were originally developed during periods of above-average rainfall. Research has found that in later decades there were periods when reliable rainfall patterns did not persist. In some cases this led to environmental degradation, a rapid decline in productivity, and increased farm abandonment, all of which have been at a great cost to individuals and the nation as a whole (McKeon et al 1990). Obviously, management strategies that have been developed during periods of low rainfall might not be appropriate during times of higher rainfall. Understanding such climatic cycles might provide an opportunity to put historical experiences into perspective and to choose management strategies that are appropriate for current climatic conditions

The application of cotton defoliants has on occasions been observed to effect the growth of native trees. Cotton growers need to know the potential effects of the defoliants on native trees in their local environment. They also need to know the implications of defoliant drift onto their spray drift buffer strips, which growers have spent many hours and dollars establishing on their farms. Spray drift from cotton defoliant chemicals has also been suggested as a potential causal agent of native tree dieback in the Liverpool Plains region of NSW and greater north-west NSW. Native tree dieback can be caused by many factors and the causal agents have not been effectively identified or justified, although many hypotheses have been formulated. Such causal theories include insect and bird attack, root pathogens such as Phytophthora cinnamomi, mistletoes, poor seedling recruitment, dryland salinity, grazing, old age, drought and waterlogging. The primary aim of this study was to determine whether cotton defoliants affect native tree species common to north-west NSW and to quantify any impacts.

Polymeria take-all is a native Australian plant which is particularly troublesome throughout the Australian cotton industry because it is difficult to control. For example, shallow chipping once per month for four months increased the dry weight production of Polymeria take-all shoots but not cotton production. Again, single applications of glyphosate and Starane, while decreasing the shoot growth of Polymeria take-all, did not increase cotton yields. In contrast, repeated severe defoliation performed under non-irrigated conditions reduced the growth of shoots and rhizomes of Polymeria take-all in an uncultivated area trial. These results have been used to help develop best management practices for Polymeria take all control which will include prevention, herbicide application, cultivation and field hygiene