Conference presentation 2008

Cotton is a global business and we have no shortage of competitors. The June USDA supply and demand report estimated world cotton production at 120 million bales with Australia producing only 0.6 million bales of these. The world's total cotton exports are 38 million bales. We compete at the top end of export cotton, in a segment of 4 million bales. If we can produce over 2 million bales of Australian cotton each year, we are a significant producer of these bales of higher quality exports. Figure 1 details the world's major cotton producers.

Small palaeochannels located in irrigated cotton fields have been identified as areas of potential high deep drainage (Triantafilis et al. 2003). Palaeochannels, being remnants of old streams and rivers, often contain a much coarser, sandier, sediment than the surrounding heavy clays. This difference is easy to see on aerial photos and there tends to be evidence of local waterlogging (T. Richards, pers. comm.). Such observations suggest differences in hydrological behaviour between the palaeochannel sediments and the surrounding clays. Other research in NSW on the hydrology of palaeochannels has either mainly looked at larger and deeper palaeochannels, such as the Namoi palaeochannel (Young et al. 2002), or looked at palaeochannels in the southern irrigation districts, which have a distinctly different origin and geomorphology (Young et al. 2002). This paper reports on the hydrological field observations as part of the project: “Geophysical and hydrological characterisation of palaeochannels in Northern NSW”.

Wincott is a network for all women involved both directly and indirectly in the Australian cotton industry, offering an alternative opportunity for them to increase their knowledge and develop their skills. The network caters to women of all levels of skills and confidence, who wish to learn more about cotton growing and the cotton industry through to women who may wish to undertake a broader role within the industry or in the wider agricultural sector. Wincott activities provide long term benefits and foster mainstream participation. The network is cost effective and uses existing industry structures and a wide range of resources to achieve its aims and objectives

Deep drainage (DD), defined as water that passes beyond the root zone, can be an important contributor in terms of recharging ground water and also in transporting certain amounts of soluble salts away from the principal root zone. As such, DD is not necessarily an adverse component in the soil or landscape water balance. However, excessive DD is not only economically poor practice but may also lead to rising ground water tables and increased solute concentrations elsewhere in the landscape. The Australian cotton industry has become increasingly aware of the large amount of deep drainage (DD) in many of the heavy textured soils (Vertosols) that are flood irrigated (Silburn et al., 2004). This information contradicted earlier beliefs in the cotton industry that 'clay soils don't drain' (Hearn, 1998). A review by Silburn and Montgomery (2003) was instrumental in helping the industry change their view of "leak proof" Vertosols, though work by Dalton (2003) stated that 'deep drainage in surface irrigated cotton systems has remained a contentious issue and one that has not been well understood or grasped by the Industry'. Seasonal deep drainage values under irrigated cotton of 100 mm and 200 mm have been calculated using volume balance measurements (Dalton, 2003), and Gordon (2000) measured seasonal deep drainage (using a large lysimeter) of 95 to 305 mm/year under drip irrigation and 165 to 180 mm/year under furrow irrigation on the Darling Downs, Queensland

The Cotton Best Management Practice (BMP) program was first introduced in 1997 to address negative public opinion of the industry and chemical contamination issues. Over the years the program has broadened to include other areas of farm management such as water, disease management, petrochemical management, soils, vegetation and riparian management.

This paper describes a method that can be used by individual cotton growers and/or cotton consultants to estimate the potential deep drainage. To do this the initial work undertaken was to identify the minimum number of observations that need to be taken to in a cotton field to give a good estimate the potential deep drainage (Figure 1). Once the number of observations needed was known the next stage involved estimating the sub-soil hydraulic conductivity using the falling head lined-borehole technique (FHLBT). To calculate the potential deep drainage also requires an estimate of how many days the sub-soil is saturated for, which growers can determine by knowing the soil moisture after irrigation using their C-probe data (Figure 1). The data generated by the growers is managed by the user-friendly Potential and Required Deep Drainage Interface housed in Microsoft EXCEL. To make the estimate of potential deep drainage more meaningful growers are also asked about the quality of their irrigation water and the crops that are to be grown during the season. This information is used to by the Potential and Required Deep Drainage Interface to determine the leaching requirement that is needed to prevent excess salts build up in the sub-soil that may affect crop yield.

This paper summarises the findings of a scoping study into the coordination of natural resource management (NRM) policy in the cotton industry, an industry which leads voluntarist environmentally adaptive farming systems in Australia. Interviews elicited assessments of the degree of NRM policy coordination in the cotton industry, as well as cotton growers' perceptions of current NRM policy, from professionals located within the cotton industry, Natural Resource Management Authorities, State and Local Governments. Interest among interviewees in the potential of co-regulatory arrangements to improve NRM policy coordination was identified. The advantages of co-regulatory arrangements for cotton growers, industry bodies and State Governments are discussed

The purpose of this paper is to provide an overview of the soil biology and what we know about its role within the cotton production system. Some of these issues fall under the concept of soil health, which we will briefly discuss. However, our mandate here is to focus on the soil biology, its ecology and responsiveness to cotton production management options. In order to achieve this we present a brief overview of components of soil biology, the impact of management upon them and what the future might promise.

In keeping with the cotton industry's mantra of "Concentrate on the things you can change and forget about the rest", I will outline the important parameters you can alter during design to optimize the overall performance of CP&LMs. This paper will examine the optimal design, installation and management of Centre Pivot and Lateral Moves or overhead irrigation systems. Topics will include optimizing the design to achieve an adequate system capacity or water supply rate, designs to minimize energy and labour inputs, and design to maximise the irrigation performance of CP&LMs in terms of uniformity and application efficiency. Discussion will follow on a range of recently completed tools that will assist surface irrigation growers and agronomists to more easily understand the practice of irrigation under CP&LMs.