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.

I would like to focus on what I believe to be some of the most important issues now and in the future for the irrigation industry and, in this particular instance, the cotton industry - - whilst however keeping in mind that I don't differentiate between cotton, com or crossbred lambs -- but more of that later.

The good news is that nutgrass can be controlled. The bad news is that successful control is a long-term venture. Nutgrass control requires good management over a number of seasons, and will be expensive, but the alternative is far worse.

Agriculture can change the hydrologic balance of a landscape either through a change from native vegetation or the addition of water by irrigation or both. Since salts move with water, a change in hydrology will mean a change in the salt balance which may cause land and water degradation. The basic principles of water and salt movement can be applied to cotton growing areas to identify potential salinity hazards both on the fann and in the catchment Salinity problems are due to the presence of a high concentration of salts in soils or waters. A sodicity problem occurs where there is a high proportion of sodium compared to other ions resulting in degraded soil.

Black root rot is caused by the fungus Thielaviopsis basicola (Berk. & Broome) Ferraris. It infects over 137 species of plants from a wide range of families including cotton (Gossypium hirsutum Linn.), tobacco (Nicotiana tabacum Linn.) and many legumes (Otani, 1962; cited in Meyer, Shew and Shoemaker, 1989). Infected plants are usually stunted during the seedling stages, leading to delayed maturity and loss of production (Young and Allen, 1991 ). Seedlings and older plants pulled from the soil often have shriveled and blackened root tissues. Survival in the soil is by thick-walled resting spores (called chlamydospores) which may remain viable in the soil for many years (Hillocks, 1992).

HOW IT RELATES TO THE CONCEPT OF BEST PRACTICE, WHAT ARE THE FEATURES OF THE TOP PERFORMERS