Stage II Objectives as defined in LWA Project Schedule dated 13/10/06:1. To develop and test a knowledge system model to improve the effectiveness of the transfer of (irrigation) information to growers.2. The model&#39s construct will aim for continuous improvement & involve partnerships across public and private sectors.3. The model is developed and tested to allow it to be rolled out across all agricultural industries in Australia.4. Engender, support and skill the &quote;Professional Irrigator&quote;

Well designed irrigation storages and water courses on cotton farms can aid in the removal of sediment, nutrients and pesticides from irrigation water and enhance their habitat value for native plants and animals. This brochure outlines key principles for increasing the water use efficiency, water quality and habitat value of cotton farm watercourses and storages. The brochure aims to inform cotton growers and consultants of the environmental and economic benefits that can be achieved easily, cheaply and within their own time frame. It is not prescriptive, but more a collection of concepts and ideas that can be adapted for different circumstances and outcomes desired by landholders.

Temperature plays many important roles in the growth and development of cotton. Low temperatures after sowing increase the time to emergence and reduce seedling vigour often leading to poor establishment, poor early growth and increased risk of seedling diseases. The tinting of crop maturity, yield and fibre quality may also be affected. Research is being conducted to improve our understanding of the impacts of temperature extremes on cotton performance. In Australian cotton production systems events where the minimum daily temperature falls below 11'C are referred to as 'cold shocks'. The number of cold shocks is used by growers and advisors in assessing retardation of crops in their areas. However, this effect has not been tested explicitly. The aim of this work was to empirically assess impacts of cold shock on pre flower development of cotton plants. Cotton seedlings were grown in controlled temperature glasshouses. Plants were transferred to cold chambers ranging from 5 to 22'C during the night period for durations from 3 to 10 d. Negative impacts were not seen until plants had been exposed to at least 10 nights at 10&#39C;, or for at least 5 nights at 5'C. When differences were generated it did not delay development to first square any more than 4 d, nor was the effect consistent. These differences translated into delays to first flower. However the delays are explained by the reduction in day degrees during the chilling period suggesting that there is no physiological damage to the plants. Improving understanding of the impacts of temperature extremes on cotton growth and development will help in developing more functional decision support tools and field management strategies

Fusarium wilt, caused by Fusaritim oxysporum f. sp. Vasinfectum (Fov), is a devastating disease in many cotton-producing countries of the world. In Australia, this disease, found first in 1993, has become a serious problem, occurring in most major cotton-growing regions and causing substantial losses (Kochman 1995). It is attributable to two genotypes of Fop; each of which belongs to a distinct vegetative compatibility group, VCGs 11 and 12, respectively (Bentley et al. 2000). Not only are the two Australian Fov strains different from the overseas Fov races in DNA fingerprints, but they have unique aesculin hydrolysis and volatile characteristics, implying that they were not introduced (Davis et al. 1996; Bentley et al. 2000)

In the Ord River irrigation Area (ORIA) INGARD' cotton varieties have been grown utilising novel integrated pest management systems (Strickland et al 2003). A winter production window, use of specific chemistry and biological control has demonstrated that acceptable yields (7-8 bales/Ha) can be consistently produced with fewer than five pesticide sprays. Aphis gossypii (cotton aphid) has been regarded as a tool in this system. During June/July when HeIiothis and beneficial insect populations are low in cotton, A. gossypii populations increase. This encourages beneficial insects into the cotton from the surrounding area. The beneficial insects feed on the aphids and in August, when Henothis populations increase again there is a resident population of beneficial insects in the cotton. In some years in Kununurra, a pesticide spray for Henothis can be avoided using this method of natural control. Data from eastern Australia suggests that cotton will recover from aphid damage provided infestations do not persist at high levels (>90% plants infested) for too long (<10 days) (Wilson & Spora 2001). These thresholds have riot been validated for winter grown cotton in northern Australia. When cotton is grown in the winter, peak flowering and fruit production occur when day length is short, radiation is low and temperature is low. Growing conditions are far from ideal. Aphids may have a Iarger impact on growth and yield than previously suspected. This paper describes some of the results from a preliminary trial carried out in Kununurra in 2003 examining the impact of aphids on photosynthesis and yield of winter grown cotton.

Most agriculturally important plants, including cotton, are colonised by soilborne fungi known as arbuscular mycorrhizal fungi (AMF). The AMF depend on the plant to supply their energy, in the form of sugars. These fungi colonise the roots internally and develop highly branched structures (arbuscules) inside individual cells of the root. Fungal filaments also grown into the soil surrounding the roots, where they absorb 'immobile' elements such as phosphorus and zinc. The phosphorus and zinc are transported to the roots and transferred to the plant in the arbuscules. Generally, the improved nutrition of the plant outweighs the cost of supplying the fungi with sugars. This type of partnership, is known as arbuscular mycorrhizal symbiosis. In the field, cotton is highly dependent upon AMF for successful growth and always forms arbuscular mycorrhizas (Nehl et al 1994).

While the importance of biodiversity in ecosystem function has been accepted for some time (Tilman & Downing 1994), only recently has the relative importance of the diversity of functional characteristics of the biota been recognised (Grime 1997). Studies of above ground diversity predominate in the literature (Loreau et a1 2001). Little is known of diversity in soil. Soil is more complex and biologically diverse than above ground ecosystems (Wardle & Giller 1997). Thus it might be argued that the loss of a small number of taxonomic groups from a complex substrate such as soil will have little impact because many different microbes would contribute to the functions of soil and therefore, many species would be functionally redundant. However, research has found that high biodiversity may be considerably more important in complex ecosystems, such as soil, than in simple systems (Grime 1997) especially when changes over time and space affect the system (Loreau et al. 2001). Soil is the location for mineral cycling, decomposition of organic materials, and flow of energy. Understanding the processes regulating these functions, and their affect on plant growth, justifies understanding the biological diversity housed in soil

Final Report

Final Report of action grant

Final Reports National invertebrate pest initiative