Regulating corn growth is vital for achieving high and stable yields, enhancing the crop’s resilience, and improving its lodging resistance.

1. Dwarfing Plants and Delaying Stem Elongation:

– Prevents excessive elongation during the seedling stage.

– Reduces plant height by 20-30 cm and increases stem thickness.

– Enhances resistance to lodging, reducing yield losses caused by lodging.

2. Promotes Robust Root Systems: 

– Increases the number of capillary roots, leading to a well-developed root system.

– Enhances the roots’ ability to fixate, absorb water, and nutrients.

– Improves drought, waterlogging, and disease resistance.

3. Ensures Comprehensive Nutrient Supply to Corn Ears:

– Shortens internodes, making it easier for roots to supply nutrients to the corn ears.

– Reduces the occurrence of incomplete, malformed, or empty grains.

2. Optimal Timing for Corn Growth Regulation

The optimal period for growth regulation is during the 7-10 leaf stage of corn, particularly at the 7-8 leaf stage, which is the most effective for preventing lodging and ensuring stable and increased yields.

If 90-95% of the corn plants have fully developed their 7-8 leaves, this is the ideal time to apply growth regulation agents. Applying these agents too early or too late can harm the corn.

1. Early Application:

– Applying before the 7-leaf stage can cause poor growth, resulting in shorter plants with weaker stems and overall poor development.

2. Late Application:

– Applying after the 10-leaf stage or beyond the jointing period can negatively affect tassel differentiation, leading to poor development, reduced pollen production, and lower pollination rates.

– Can cause abnormal internode shortening, affecting the base’s robustness and reducing lodging resistance, which can lead to poor growth and reduced yields.

3. Methods and Precautions for Using Growth Regulators

Types and Dosages of Corn Growth Regulators:

1. 30% Diethyl aminoethyl hexanoate·Ethephon SL:

– Apply during the 6-8 leaf stage, no later than the 10-leaf stage.

– Use 300-450 ml per hectare, mixed with 225-300 kg of water.

2. Chlormequat Chloride:

– Apply 220-300 g of 50% solution per hectare, mixed with 225 kg of water.

3. Mepiquat Chloride:

– Apply 300-450 g of 25% solution per hectare, mixed with 600 kg of water.

4. Uniconazole:

– Apply 300-375 g of 5% solution per hectare, mixed with 375 kg of water.

Additional options include using uniconazole, ethephon, and other growth regulators.

4.Principles and Precautions:

1. Application Principles:

– Apply regulators when the leaves are dark green, thick, and soil moisture is sufficient.

– Increase dosage in fields with excessive nitrogen or vigorous growth.

– Avoid using regulators in weak, yellow, or poorly nourished plants.

2. Spraying Techniques:

– Do not spray the entire plant; ensure even application without overlapping.

– Follow the principle of spraying high but not low, avoiding overly small plants.

3. Weather Considerations:

– Spray less during hot, dry periods and more during rainy, humid periods.

– Avoid spraying on windy or rainy days. If heavy rain occurs 4-6 hours after spraying, reapply at half the original dosage.

– Preferably spray in the morning or evening on sunny days for better absorption.

5.Managing Overuse or Phytotoxicity:

1. Immediate Actions:

– Flush the leaves with water to dilute residual or absorbed chemicals.

– Apply quick-acting nitrogen fertilizers to stimulate growth and alleviate damage.

2. Foliar Application:

– Spray 2-3 times with a solution of potassium dihydrogen phosphate and brassinolide every 7-10 days to minimize adverse effects.

Ensuring proper growth regulation at the 7-10 leaf stage is crucial for maximizing corn yield. Missing this window means you should not apply growth regulators.

Any interest in crop cultivation knowledge, please feel free to contact me.