Soil moisture extraction under fully irrigated conditions was the same in BollgardII and conventional varieties, except where season length allowed later crop and leaf growth in the conventional variety. *BollgardII grown under fully irrigated conditions maintained a yield advantage and required 6.3ML/ha of irrigation water as opposed to 7.0ML/ha for the conventional full irrigation treatment. *A greater reduction in water use efficiency was apparent in BollgardII where moisture stress was experienced at or close to cut-out, except where late season rainfall alleviated this stress.

This pilot experiment at Carroll and Narrabri investigated the yield and fibre quality benefits of application of foliar potassium, phosphorus and micronutrients to a high yielding Bollgard II and Roundup Ready variety.

Waste-stream materials can be obtained at little or no cost but their value in agriculture is limited by transportation and application costs. To be practical and economic, waste products must be applied on agricultural land which should be located near the production facility. In this study we examine the effects of a wide range of organic amendments on cotton soil and the associated changes due to their application. If application of these materials proves beneficial, it will benefit not only cotton farmers but will also offer an economic and environmentally acceptable means of waste disposal.

Our research group set out to examine three topics: we documented the diversity of common microbes in cotton soils and followed this with research targeting interactions between microbes and seedling pathogens, we examined the impact of cultivation of cotton on diversity and abundance of AM fungi, and we commenced a study to determine the importance of microbes in sequestering carbon in soil.

Soil quality issues have been researched within a crop rotation experiment that started in 1994 at Narrabri. It compares three crop rotations that have included or excluded legume phases throughout this period. The data presented here relate to the most recent 2-year cycle of this experiment. Following cotton harvest in all three rotation systems in May 2004, oats was sown in two systems. Following oat harvest, the soil was either left fallow (oat-fallow treatment) or vetch was sown in the April 2005 and green-manured in August 2005 (oat-vetch treatment). In the third treatment, vetch was planted in May 2004, green-manured in August 2004 and cotton sown in October 2004, vetch was sown in May 2005 and green-manured in August 2005 (vetch-cotton-vetch treatment). Cotton (cv Sicot 71BR) was sown in October 2005 across all systems.

The way the cotton plant responds to water stress on different soil types changes will influence its requirement for water and may change the irrigation strategy used if yield potential is to be achieved. Soil types are different not only in the total amount of available moisture that they hold, but also in how readily the moisture is made available to the plant. This response has been investigated in a three year project measuring plant water stress under different irrigation conditions during early flowering on three soil types. Initial interpretation of results suggests that plants differ in their response to soil moisture stress on light soils compared with heavier soils, when using a standardized measurement of soil moisture status i.e. the fraction of transpirable soil water (FTSW). FTSW is calculated by changing available water content of the soil to a percentage. The advantage of using FTSW to define soil moisture holding capacity is that it allows people working across different known soil types to compare soil types in terms of irrigation schedule and plant moisture availability.

The cost-benefit analysis of 43 fields of cotton defoliated using at least one pass with variable rate chemical application, showed significant benefits for the farmers involved. The average savings in chemicals when compared to what would otherwise have been applied was $11.82/ha. The farmer was able to save, on average, 25% of his chemical bill. In most situations this savings in chemicals more than covered the cost of the Belt-Wide Agriculture service ($10/ha) and left around $4.23/ha in the farmers pocket.

High temperature stress adversely affects cotton growth and development. This paper presents preliminary results of studies evaluating methodologies that measure the ability of cotton to tolerate high temperatures. Simple methodologies that measure cell damage and loss of enzymatic function are being employed to measure the tolerance of cotton cultivars to high temperatures. Early results suggest that there is some variation among cultivars in their ability to withstand high temperatures under laboratory conditions. These methodologies will be further evaluated to establish their value in identifying thermotolerant cotton cultivars for potential use in cotton breeding programs

Northern Australian regions could become significant cotton producers in the future if regulatory issues and negative industry perceptions can be overcome (Yeates 2001). In Western Australia, significant production-based research has been conducted at Kununurra and Broome in order to evaluate the feasibility of a winter cropping strategy for cotton. Sustainability has been a focus of research and the development of a RMP for Bollgard II is an essential prerequisite to obtaining regulatory approval. For seven years, between 1997 and 2003, a range of crops was assessed for their usefulness as refuge crops in a future Ord Stage 2 cotton industry and a draft RMP produced.

Magnet is a blend of synthetic plant volatiles that attracts Helicoverpa moths, especially females. Currently, research is determining strategies to utilize this product in cotton pest management. One strategy is to mix Magnet with synthetic insecticides and use the product as attract and kill (Pyke et al. 1987) on Bollgard ) cotton to reduce Helicoverpa populations on adjacent conventional cotton crops. The study reported here showed that, Magnet mixed with insecticide and applied to Bollgard cotton crops, can reduce populations of Helicoverpa spp. on adjacent conventional cotton crops. The study also showed that using Magnet in this way, growers could reduce insecticide use and costs for control of Helicoverpa spp. on conventional cotton crops