The Australian cotton industry has made considerable yield gains by improving genetics and agronomic management, which is ultimately limited by the environmental constraints in our growing regions. One of the major factors limiting yield in Southern NSW is the unpredictably cool start to the cotton growing season. This has a negative impact on grower’s ability to establish a consistent plant stand within an optimum planting window that allows sufficient length of season to obtain high yields.

Germinating cotton seed is an interaction between soil temperature, moisture and seed/soil contact. Depending on the season most growers are able to achieve a uniform, consolidated seed bed for optimum seed/soil contact but must react to fluctuating temperatures and consider irrigation water temperature at the time of planting. 

The results from this project suggest there is no silver bullet to improve yields. The attempts to improve crop establishment and increase early season growth returned nil significance during the seasons they were tested. The main outcome present across all experiments was that other agronomic management such as soil health, pest and disease pressure and seasonal environmental challenges limited the yield more than treatments imposed to affect establishment. 

Application of plant hormones to increase early season growth and boll loads have returned mixed results from work conducted in Australia and internationally. Irrigation and nutrition management play a large role in the efficacy of such products having an influence on yield components. For example, where soil conditions resulted in the crop experiencing potassium deficiency late in the season and undergoing early senescence, a review of the treatment effects of the products used is required. This work needs further investigation targeting compensatory growth and stress alleviation.   

Technologies such as biodegradable plastic applied over the seed line show promise to improve establishment but is highly dependent on planting date. Early planted crops experience an increased response to temperature/moisture dynamics when compared to late planted crops. The exercise of applying this plastic is expensive and requires a yield increase of 1 bale/ha in order for it to be worthwhile. Therefore, yield gains expected from application of the plastic should be done so on fields where there is no expected yield constraints from other factors such as disease or nutrition. 

Evaluation of factors limiting yield potential should be considered from a whole farm perspective and not just one facet of crop agronomy. While achieving a consistent plant stand is crucial to achieving high yields; other factors like nutrition, irrigation management, pest and disease control and seasonal conditions have a considerable influence on yield. Tackling all of this to improve yield is a massive task but over time with the skill set of the Australian cotton industry it can be done.