Understanding the Metrics of Growth
According to the CSD Ambassador Network’s First Flower Snapshot, there are clear targets in that are indicative of a potentially high-yielding crops. These targets include:
- Day Degrees to First Flower (DD1532): 584
- Days After Sowing to First Flower (DAS): 60-70
- Plant Height: 50-60 cm
- Squaring Nodes: 9+
- Total Nodes: 16+
- Nodes Above White Flower (NAWF): 8+
- 1st Position Retention Percentage: around 80% in the traditional and 90% in the southern valleys
- Growth per Node: 5-6 cm
It’s important to understand that achieving the best potential yield from the CSD analyses requires viewing these metrics collectively– like a blueprint. However, this doesn’t imply that high yields can only be achieved from this specific combination of metrics. High yields can be achieved by having other metrics in a better place when others are not so favourable. For example, too high retention with less than optimal growth characteristics can challenge yield; it maybe be better to have a bigger plant when retention is high. CSD tools such as BARRY, are invaluable in these instances to assist in determining how these variables interact with each other.
Setting the Stage: Planting and Temperature Management
The goal is to achieve a robust plant architecture by the first flower, which requires managing several factors diligently:
- Temperature Management: Ensuring the seedlings are planted when there is minimal risk of temperatures dropping below the critical threshold. Planting when it is warm means that there are increased chances of leaves and stems growing optimally.
- Nutrient and Water Use: Delays in reaching the first flower increase the plant’s consumption of nutrients and water. Efficient use of these resources begins with optimal planting decisions influenced by regional climate forecasts. Not to mention that cool conditions limit root growth and this can reduce the crops ability to take up moisture and nutrition.
- The plant’s ability to cope with and compensate for the impact of seedling diseases such as damping off or black root rot and early season insect pests such as thrips is also improved through experiencing warmer growing conditions.
The Crucial Early Weeks
The period three to four weeks post-planting is critical in setting the trajectory of growth for cotton seedlings. Temperature plays a pivotal role during this phase. If average daily temperatures fall below 15.6°C, development can be significantly slowed or even halted, leaving the seedlings dormant and more susceptible to diseases and pests. This early vulnerability underscores the importance of choosing the right planting date—a decision supported by CSD’s simulated time to first flower (STEFF) tool which forecasts the flowering time based on temperature patterns.
Regional Variations and Their Impact
The time to reach the first flower varies significantly across Australia, influenced predominantly by temperature. Northern regions, experiencing warmer averages, tend to have faster growth cycles compared to the southern regions where growth may be impacted by cold snaps. This regional discrepancy necessitates tailored management practices to ensure optimal growth no matter the climate.
Node Development and First Irrigation Timing
Node development is a clear indicator of a cotton plant’s health and potential yield. Optimal node development is typically observed in warmer conditions, which also correlates with quicker day degree accumulation. Conversely, cooler temperatures can slow this progression, affecting the overall crop development schedule, and also in many instances reflects poorer growth
The timing of the first irrigation is another crucial factor that can dictate the success of the crop. It encourages root expansion and sets the foundation for the plant’s resilience during the flowering and boll development stages. Factors like soil moisture content, weather forecasts, and crop growth stages must be considered to optimise this first irrigation without inducing moisture stress. A rule of thumb to help time first irrigation is to ensure that white healthy roots continue to grow deeper into the soil profile.
The Role of CottonTracka and BARRY
CSD’s CottonTracka is an invaluable tool for growers, offering the ability to monitor and compare pre-flowering height and node development against established industry standards. This real-time data when tracked against optimal targets ensures that the crop is being steered towards maximum yield potential and can highlight if agronomic interventions are necessary. This tool can be found on the CSD website exclusive to CSD members.
BARRY, a yield prediction model developed by CSD & CSIRO can be used to explore different combinations of growth and development metrics to understand how a crop can achieve better yields when it does not quite fit the prescription of a high yielding crop.
Combating Pests and Diseases
Early season growth is not just about hitting physical growth targets; it’s also about protecting the crop. The prevalence of pests such as mirids and thrips, along with diseases like Black Root Rot, can significantly impede growth. An actively growing plant is the best defence, as it can better compensate for damage caused by these threats, at least earlier in the crops’ life.
Conclusion
The beginning stages of the cotton growing season is a critical period that sets the tone for the rest of the growing season. Guided by the growth metrics and management strategies outlined as a result of analysis of the CSD Ambassador Network, Australian cotton growers can significantly enhance their crop’s yield potential and seek opportunities to improve when situations are not optimal. From selecting the optimal planting date to managing temperature and timely irrigation, each decision plays a pivotal role in the journey towards a high-yielding crop. With tools like FastStart Field Forecast, STEFF, CottonTracka (including BARRY) at their disposal, growers are better equipped than ever to navigate the complexities of cotton growing, ensuring that every crop has the best possible start.