July 21, 2003

COTTON growers, consultants and agronomists were briefed on the latest industry research at the annual CSIRO/CSD review at Narrabri last Tuesday and Wednesday.

CSD general manager Adam Kay said more than 100 people attended the two-day conference, witnessing 17 presentations on a range of issues, including ultra-narrow row cotton, managing for earliness, fusarium ecology, fibre quality, potential new varieties, and issues such as nutrition, weeds, residual herbicides and water-use efficiency.

Reflecting the keen interest in new transgenics, an entire day was devoted to Bollgard II management and research, with contributions from CSIRO, the Cotton CRC, Monsanto and CSD (Cotton Seed Distributors).

Key messages from the review included:

Bollgard II:

· Indications of a potential suite of new CSIRO conventional and Bollgard varieties in the pipeline, expressing superior yields, fibre quality and disease resistance to those currently available;

· Potential new germplasm being investigated from countries such as China, Mexico, Peru, Guatemala, Tajikistan and Arizona.

Crop nutrition:

· Evidence that phosphorous and potassium remain marginal in many cotton growing soils, with sodicity (high sodium levels) also a problem, limiting productivity and the uptake of other elements;

· Potential for significant yield increases from the use of vetch as a green manure legume in rotations with cotton, and also with wheat in rotation.

Fibre quality:

· A marked decline in average micronaire in the cotton crop from 1985 to 1995, but reversing since then, moving sharply upwards;

· Indications that one third of all micronaire changes are due to climate and to crop management, with micronaire rising in hot seasons and declining in cold seasons;

· Suggestions that there is no single factor impacting on fibre quality, but rather a range of factors including ginning, harvesting, climate, management and varieties.

Weeds:

· Evidence suggesting that weeds cost the cotton industry up to $100 million annually, with on-farm weed management costs varying from $100-$400/ha, plus yield reductions of up to $500/ha;

· Evidence of a significant change in the weed spectrum in cotton fields, with only six of the top 10 weeds in 1989 persisting in the top 10 in 2000;

· Evidence that some weed seeds can lie dormant in the soil for up to 30 years, hence the importance of persistence in weed control, and in reducing the soil seed bank;

· Compelling evidence that herbicide use can be reduced by up to 85 per cent, weed control costs by 50 per cent, while increasing yields by up to 10 per cent;

· No evidence yet of herbicide resistance.

Water-use efficiency:

· Significant benefits can be gained by developing better irrigation strategies in each region;

· Development of a water use efficiency calculator by CSIRO and the Cotton CRC, which will assist in better on-farm water management "more crop per drop".

· The launch in September of new risk management support software including WaterPAK and HydroLOGIC which can be used in irrigation scheduling and in "what if" scenarios to determine the consequences of irrigation on yield and maturity.

UNR:

· The inconsistency of results from ultra narrow row research, but evidence of no significant difference in yield, maturity, fibre quality or number of bolls compared with conventionally grown cotton;

· All trials so far have been with normal leaf varieties, with the latest trials involving 25cm row spacings. Future trials will look at 38cm row spacings.