With the "Start of Autumn" (Lìqiū) solar term now past, China's autumn grain production has entered its most critical stage of yield formation. To confront the multiple challenges of high temperatures, drought, flooding, and pests and diseases, a field management technique known as "One-Spray, Multi-Effect" is emerging as a powerful tool for securing the harvest. This technique involves the scientific blending and single-application spraying of foliar fertilizers, plant growth regulators, and pesticides to achieve the combined goals of disaster mitigation, nutrient supplementation, pest and disease control, and growth promotion, providing strong technical support for stable and high yields of rice, corn, and soybeans.

General Application Guidelines:

Optimal Timing: Conduct spraying operations before 10 a.m. or after 4 p.m. to avoid the high temperatures of midday and reduce evaporation of the solution.

Weather Conditions: Proceed only when wind speed is below Level 3. If moderate to heavy rain occurs within 24 hours of application, a follow-up spray is necessary.

Equipment and Volume:

Plant Protection Drones:

Flight Speed: 5-7 meters per second.

Flight Altitude (from crop canopy): 2-3 meters for light-duty drones (payload <50L); 2-4.5 meters for heavy-duty drones (payload ≥50L).

Spray Volume per Mu (approx. 667m²): Generally 1.5-3 liters; for soybeans, over 2 liters is recommended.

Key Points: The solution should be prepared through secondary dilution on-site and used immediately. Add spray adjuvants (such as deposition aids) to prevent drift and evaporation.

Ground-Based Machinery (e.g., High-Clearance Boom Sprayers):

A higher spray volume is required to ensure uniform coverage: over 30 liters per mu for rice and corn, and over 15 liters per mu for soybeans.

For different crops, strategies vary and must be tailored to local conditions and seedling status.

For rice, the core objective is to protect panicles, increase grain weight, and defend against disasters. In the Northeast region, the focus is on managing waterlogging, lodging, and low-temperature damage. In the middle and lower reaches of the Yangtze River and the Southwest region, the priority is combating high temperatures and drought. The base formula should include potassium dihydrogen phosphate to enhance plant stress resistance. For waterlogged plots, a timely foliar spray of urea and potassium dihydrogen phosphate after drainage can quickly restore growth. Under high-temperature and drought stress, anti-drought and anti-stress agents can be added. Simultaneously, targeted control of key pests and diseases such as rice blast, sheath blight, rice false smut, as well as stem borers and planthoppers, should be carried out based on local conditions.

For corn, the key tasks are to enhance pollination, promote grain filling, and prevent premature senescence. The Huang-Huai-Hai region must address the impact of high temperatures on pollination, while the Northeast should guard against early frost and lodging. The optimal application window is 5-7 days before the wax ripe stage. A combination of products like potassium dihydrogen phosphate, urea, and brassinolide can be used to both supplement nutrients and regulate growth. High-efficiency fungicides and insecticides should also be applied simultaneously to tackle common issues like southern leaf blight and the widespread corn borer.

For soybeans, the overall goals are to promote early maturity, increase grain weight, and mitigate disaster impacts. In normally developing fields, the primary measure is to spray potassium dihydrogen phosphate to delay leaf senescence and improve photosynthetic efficiency. For disaster-affected fields, the approach must be flexible: add anti-drought agents for drought-stricken areas; apply urea and potassium dihydrogen phosphate after draining waterlogged fields; and spray phosphate-potassium fertilizers or liquid films in areas threatened by early frost. Furthermore, depending on regional specifics, it is crucial to control key pests and diseases like downy mildew, pod borers, and bean bugs to minimize losses.

The "One-Spray, Multi-Effect" is a highly efficient and scientific comprehensive field management technique. Its successful implementation depends on an accurate assessment of crop growth status, weather conditions, and pest and disease patterns. Only by truly tailoring strategies to local conditions and specific timing can its multi-faceted benefits be maximized, laying a solid foundation for a bountiful autumn harvest and ensuring national food security.