STANDOUT DRYLAND VARIETY CHOICES

As dryland growers are dependent on rainfall to produce yield, a variety needs to be able to respond to favourable conditions if and when they occur. The ideal variety is a vigorous, longer season variety, which will be able to hang on in dry times and then rebound and quickly put on yield when rain arrives.

Sicot 748B3F is derived from Sicot 74BRF, and has the characteristics if yield potential fibre quality package which is desirable in dryland production. It is a full season indeterminate variety which has a vigorous growth habit and may require growth monitoring and management to ensure plants don’t get too tall. As with all low-density varieties, care should be taken when planting this variety and an additional one to two seeds per metre be planted to ensure a desired plant population is achieved.

Sicot 746B3F also has a Sicot 74BRF background. It is a full season indeterminate variety which is best managed to reduce any stress events, which can be particularly difficult in a dryland farming setting. In CSD’s variety trials, Sicot 746B3F has shown some increased sensitivity to the extreme heat of some western regions, so is more suitable to the milder conditions of the eastern growing regions. CSD dryland variety trial results have also shown a slight reduction in length compared to Sicot 748B3F. As is the case with Sicot 748B3F, Sicot 746B3F is a low-density seed variety and will therefore require extra care and favourable conditions to achieve the desired establishment. This characteristic does however translate to an increased turnout percentage.

Sicot 714B3F has a background from Sicot 71BRF and is a mid to full season maturing variety which has historically performed well in dryland production areas. It achieved an impressive yield result from the Bongeen variety trial in 2016/17 yielding 11.69 b/ha on a single skip configuration. Sicot 714B3F has also demonstrated superior  establishment in dryland conditions over Sicot 748B3F. Therefore, in marginal planting conditions, Sicot 714B3F is a preferable option in terms of gaining a viable plant stand. It will be well suited in all growing regions but may offer a high yielding option for short season areas. Care should be taken in crop management immediately post flowering as this variety quickly accumulates fruit. Amassing a high boll load in a short period of time will stress late season boll retention as well as predisposing this variety to late season premature senescence.

ROW CONFIGURATION – THE DECISION PROCESS

Selecting the right planting row configuration is a critical factor when planning for dryland cotton. Depending on seasonal factors, it will impact on the final yield, fibre quality and the profitability of your crop. There is no one row configuration that suits all situations; however, choosing the right configuration is a calculation involving yield expectations, water availability, plant available water holding capacity (PAWC), risk aversion, how the row configuration fits into machinery wheel spacing available, and the reliability of the seasonal climatic outlook.

1. PAWC – the amount of water that soil can hold is a critical factor in the crop’s potential success and a grower’s row configuration choice. Row configuration selection is about managing the soil water bucket. In low PAWC scenarios of between 150-180cm, wider row configurations should be employed, whereas in high PAWC  situations, tighter/narrower configurations are better options.
2. Planting date – In most regions, planting later into the planting window is better for yield potential on average. In dryland cotton, your choice of planting date is very
   much dependent on when planting rains occur. Planting early in the window can expose dryland crops to December/January heat as well as extending the time before summer storms/rainfall arrives. As a general rule of thumb, wider row configurations can be employed when planting earlier, to extend the bucket of soil moisture available to the crop, especially around flowering. Late season plantings can have an issue with reaching maturity before inclement weather hinders harvest, so the season length can be managed using tighter row configurations. As the dryland cotton industry expands into new regions, the definition of what constitutes early, mid and late planting date for each locality will vary significantly. It is important to consult with your agronomist to discuss how your region and planting date interact.
3. Forecast/risk profile – Regions and seasons have different risk profiles. Naturally, in hotter regions and drier years, wider row configurations will enable the cotton plants to access more soil moisture and maintain both yield and fibre quality. Tighter configurations allow the yield potential to be maximised for wetter years and cooler regions. The diagram to the right illustrates the interaction of these three variables in a matrix. If your situation falls within the red shaded area then a wider row configuration such as super single may be a consideration. The orange, yellow and green sections, for which the majority of dryland cotton planting occurs, highlights
   considerations for either double or single skip planting options. The blue area would get the best result using a solid planted configuration. The decision is ultimately based on an individual’s attitude to risk and seasonal forecasts.

ROW CONFIGURATION AS A RISK MANAGEMENT TOOL

There is an important interaction between row configuration, yield potential and fibre quality. As the row configuration widens, inherently there is the potential for less yield in better seasons, and this difference can be quite large. However, wider configurations yield similar to tighter configurations in harder years, while being better able to maintain base grade fibre quality. Therefore, varying row configuration is a method by which yield can be secured and quality discounts minimised. There is also an opportunity to
manage variable costs. The combination of these factors reduces the risk of growing dryland cotton.

The relationship between yield and fibre quality in dryland cotton is shown in graph to the right – a summary of 77 dryland row configuration trials conducted by CSD since 2016. Please note that, within many cases in these trials, the final yield was not significantly affected by the choice of row configuration.

Additionally, the use of row configuration is a method by which season length can be managed. In dryland cotton, the length of the growing season, and more critically the flowering period, is important. The longer the flowering period can be extended, the higher the yield potential because there is more moisture to access. This has the added benefit of opening up more of the time in which to utilise summer rainfall.

The NAWF vs Day Degree graph to the right highlights that there was a 200-day degree difference between cut out of the single and double skip, and a 340-day degree difference between the super single row configuration and solid planting scenario in these trials.

HOW DOES ROW CONFIGURATION AFFECT THE GROSS MARGIN?

The example in Figure 4 looks at different growing scenarios, and the influence of four planting row configurations on the final gross margin.

Yellow line/squares: In this scenario, representing a very tough growing season, yields for all row configurations are very similar at about 1.5 b/ha. However, the super single configuration is still able to post a break even gross margin.

Red line/squares: This represents the average growing conditions experienced over past summers. As the line is very close to horizontal, this
means there is minimal difference in gross margin between the four row configurations. The level of production risk is quite varied between each.

Blue line: High risk is associated with the solid plant where the grower is heavily reliant on more frequent rainfall to ensure yield and fibre quality are maintained. There is less risk associated with the double and super single scenarios, as the plants would have more soil to forage for moisture, to help to maintain their yield and fibre quality. Timing of in crop rainfall would also be less critical. The financial outlay to grow the crop is also less in the wider skip configurations. Thus, for considerably lower risk, the same amount of money is returning to the farming operation per hectare.

Green line/squares: This shows the potential upside under very good seasonal conditions. Note that even as the yield of the solid plant increases it still does not give a dramatically better return to the operation as both single and double skip stay close to it. Consequently, at yield levels below 4 b/ha, a wider skip row configuration
will give the better dollar return; at higher yield level potentials, tighter configurations will be more favourable.