A series of trials over the past five seasons has shown wide variation in seed emergence and plant establishment in cotton crops within and between regions.

The data shows that these variations are not simply due to germination percentage or seed vigour, but also to field preparation, seedbed conditions, time of planting, pre and post emergence soil moisture, climatic, disease, pest and weed conditions, and to irrigation strategies.

Cotton Seed Distributors extension and development agronomist, John Marshall, addressed many of these issues in the weekly CSD Web on Wednesday video (19/11/03).

He said that in trials conducted at Emerald and at St George this season, with the same high quality seed lot of the same variety (Sicot 80 with a 96 per cent germ and 184 SVI), vastly different seed emergence and plant establishment results were achieved.

“At Emerald, it was watered up on September 20, experienced extremely ideal conditions for germination, resulting in rapid emergence and an extremely high establishment, close to 95 per cent.

“In contrast, at St George, with exactly the same seed, the crop took close to 25 days to reach 95 per cent emergence, and that stand represented only slightly above 60 per cent establishment.

“The reasons for this very slow start were the fact that 20mm of rain and very cool conditions occurred during the period just after planting. Once again, this illustrates the effect of climatic conditions on the same lot of seed,” John Marshall said.

He said the five years of trial information accumulated by CSD will be published in booklet form for use by growers as a guide to maximising plant stands over a range of environmental and seasonal conditions.

Trial information for specific sites can be found on the CSD website in the Trials on Line section, under the Trial Tracking tab.