Why Haven’t Average Yields Increased?
Rice is often considered an easy crop to grow, but for some, it's treated as an opportunity crop rather than a priority. This has impacted yields in various ways, especially when best practices are not consistently followed.
Key Challenges:
- Late Sowing: Many growers sow later than ideal, which increases the risk of cold-induced sterility during critical growth stages.
- Establishment Issues:
- Drill Sowing: Problems with poor layouts, inadequate ground preparation, and water ponding between flushes.
- Aerial Sowing: Challenges with ducks, wind, and muddy water.
- Neglecting Field Nitrogen (N) Variability: Field variability needs to be addressed before Permanent Water (PW) is applied.
Prioritize Rice and Follow Best Management Practices:
- Early Sowing: While early sowing might lead to difficult establishment and a higher risk of poor grain quality, late sowing is more detrimental, increasing the risk of cold damage at microspore and resulting in delayed harvests.
- Sowing Methods and Layouts:
- Zero slopes increase the risk of poor establishment, especially when drill sowing, and lack of surface drainage compounds issues when rain occurs.
- Shallow beds provide better drainage, particularly during critical times.
Nitrogen Management:
- Applying pre-PW urea is crucial. Research shows that repeat rice crops require higher nitrogen levels than first crops, and nitrogen application should occur pre-PW or during tillering for optimal yield.
- Nitrogen Risks: High pre-PW urea rates can cause lodging in hot seasons or floret sterility in cool seasons.
Long Grain Varieties – Agronomic Characteristics:
- Cold Sensitivity: Topaz and Doongara are extremely sensitive to cold during microspore and flowering stages. Deep water is necessary during this period to protect the crop.
- Nitrogen Splits: A 70:30 nitrogen split (PW) helps reduce cold sensitivity and lodging, especially in Langi.
Zinc Deficiency:
- Zinc deficiency can starve rice seedlings for oxygen soon after PW application. High pH soils, high levels of soil phosphorus (P), or subsoil exposed after landforming are common causes.
Repeat Rice Nutrient Experiment:
- The experiment highlights that increased pre-PW urea rates provide the best yield, but soil testing is vital to ensure optimal nutrient levels (P, S, Zn).
In Conclusion:
- To improve yields, growers need to follow timely management practices, address field variability before PW, and apply appropriate nitrogen rates based on soil conditions and crop history. Utilizing tools like the UNE grower dashboards can significantly improve crop management decisions.