What are the steps involved in producing a weather forecast? (a) Collection of meteorological information (b) Processing of this information (c) Preparation of the forecast (d) Distribution of this forecast (All this must be done in a time frame that enables step (d) to be actioned before the forecast period begins.) Advances in each of these four steps have been considerable over the last decade, and are resulting in more accurate and readily available information to assist with decision making in rural affairs. We will now look briefly at some of the progress in each area.

In 1992 we started work on an alternative way of detecting pesticide residues, based on the application of medical immunodiagnostic tests. This type of technology was introduced to the cotton industry last year, through the Lepton (R) test for Heliothis speciation. Immunoassays use antibodies that have been prepared in rabbits, mice or sheep to a particular pesticide. The pesticide molecules are too small to raise an immune response by themselves, so much of the art in developing a pesticide immunoassay consists of coupling a chemical analogue of the pesticide to a carrier, usually a protein that is foreign to the animal being immunized. The analogue must retain all of the characteristic features of the pesticide, but have a new chemical group in its structure that can act as a handle for coupling to the protein. Once coupled to the protein, the pesticide-protein "conjugate" is usually able to evoke antibodies, but for a useful test to be possible, antibodies must be evoked that can bind to the free pesticide, as it would appear in water and other environmental samples.

The irrigated cotton industry in Australia has been developed around major river systems to allow water to be pumped to farm storages and then recirculated on farm using flood irrigation techniques. Recent work conducted by the Department of Water Resources NSW, showed that levels of some pesticides, particularly endosulfan, exceeded ANZECC guidelines for the protection of aquatic ecosystems in river systems in northern NSW. Because of the close proximity of natural water courses to cotton paddocks, a major national research programme was established in 1993, jointly funded by the Land & Water Resources Research and Development Corporation (L WRRDC), the Cotton Research & Development Corporation (CRDC) and the Murray Darling Basin Commission (MDBC). An important part of this program has been a project designed to estimate the contribution that the aerial application of pesticides (specifically endosulfan), makes to chemical loads in the riverine environment by primary droplet transmission (drift), subsequent volatilisation and transmission on dust particles.

In 1994, the Australian cotton farmer must use a wide range of costly chemicals to harvest a profitable crop. These chemicals vary significantly in their degree of hazard. Some chemicals (e.g. the organophosphates) directly threaten humans and other animals, because of their effect on nervous function. Others, such as the pyrethroids, are innocuous to humans, but toxic to fish. Still others, such as the esters of 2,4- dichlorophenoxyacetic acid (2,4-D) used on crops like wheat grown in rotation with cotton, are of concern because of their mobility in air and their possible effect on nontarget crops such as grapevines or cotton. But currently, most attention is focussed on those that have potential environmental effects, such as endosulfan

In this article I will chiefly focus on the this problem on soils with adequate levels of soil potassium. First by briefly describing the factors that may cause a crop to develop premature senescence under these conditions and second by summarising some preliminary research on methods of predicting and preventing this problem.

The Total Catchment Management ("TCM'') philosophy was formalised in NSW in 1980 with the passing of the Catchment Management Act which provides a clear legislative base for the operation of TCM Committees and Catchment Trusts. It is worth stating the functions of TCM Committees as set out in that Act.

Premature senescence caused by potassium deficiency has been most severe on soils that are considered deficient or marginal in potassium for cotton growth ie. having a soil test result less than 0.4 meq K/lOOg (Kirby and Adams, 1985). There are other factors which can induce potassium deficiency in plant tissues such as heavy fruit load on small plants and plant uptake that is impaired for various reasons. These are the subject of current research by CRDC funded projects and will be discussed in other papers at this conference. This paper will focus on the question of soil deficiency

A vision guidance system has been designed, built and commissioned which steers a tractor relative to the rows of a crop such as cotton . It was required to be insensitive to additional visual "noise" from weeds, while tolerating the fading out of one or more rows in a barren patch of the field. The system integrates data from several crop rows, testing for image quality. At the same time, the data processing requirements have been limited by the use of frame-sequential strategies to reduce the image space which must be processed. The current prototype employs an embedded 486 PC notebook computer and shows great promise of cost effective commercial exploitation. Experimental results are reported and further sensing systems are explored to enhance performance in difficult environments.

Since the late 1940s, synthetic herbicides have provided effective and economical control of many weeds. However, an excessive reliance on chemicals has created problems related to their overuse, such as toxic residues in plant and animal products and the pollution of soil and waterways. Furthermore, chemical herbicides fail to provide adequate control of some weeds, and increasingly stringent regulatory requirements for registration of new pesticides makes the development of new herbicides prohibitively expensive. These factors have lead to an increasing interest in the use of biocontrol agents to replace or augment traditional weed management systems. Biocontrol agents have less adverse effects on non-target species and are perceived by many to be more environmentally friendly than synthetic herbicides. They are also likely to provide greater operator safety than most synthetic herbicides, some of which have been shown to be carcinogens or have other adverse effects (Brown, 1992).There have been two main approaches to biocontrol of weeds using plant pathogenic fungi; the classical approach and the inundative (or bioherbicide) approach

Thrips are important pests in Australian cotton and are also key predators of spider mites. Despite their pest status thrips have received little attention, with little known of their species composition, ecology, or their effect on cotton maturity or yield. The aim of the experiments described below is to investigate the effect of early season thrips infestations on the development, maturity and yield of cotton in order (1) to derive thresholds for thrips control, (2) to develop appropriate sampling recommendations and (3) to obtain infonnation to enable the effect of thrips to be linked with the Oz.cot and Cercot cotton crop models.