Flood Control and Disaster Mitigation Techniques for Corn in Southern China

Currently, the southwestern and southern regions of China have entered the flood season, with a high frequency of natural disasters. According to weather forecasts, heavy rain is expected in parts of the Jianghan, Jianghuai, northern and western Jiangnan, northern Guangxi, and Guizhou, with local heavy downpours, short-term intense rainfall, and thunderstorms. To ensure the safe production of corn, the Corn Expert Guidance Group of the Ministry of Agriculture and Rural Affairs, together with the National Agricultural Technology Promotion Service Center, has proposed flood control and disaster mitigation techniques for corn in southern China, focusing on “drainage, seedling support, fertilization for growth, pest and disease control, and replanting or changing crops.”

1. Timely Drainage and Moisture Regulation

For low-lying areas prone to flooding, it is essential to open ditches in advance, dig drainage pits, and prepare for drainage. After the rain, promptly clear ditches to facilitate drainage. For flooded areas, mechanical drainage methods should be used to quickly remove standing water and reduce soil moisture. It is also important to plow and cultivate the soil to help the corn’s root system and plants recover, preventing early aging or death caused by waterlogging.

2. Classification of Seedling Support and Weed Removal

After heavy rains and strong winds, manage the field based on the extent of crop lodging. For fields with minor lodging, plants can naturally recover without intervention. For fields with severe root or stem lodging, especially those where plants have fallen flat after tasseling, it is crucial to manually upright the plants and mound the soil around the roots. For fields with broken stems, those with mild damage can have broken plants removed; in more severe cases, consider silage to preserve the harvest.

3. Post-Flood Fertilization for Growth

For waterlogged fields, manage them promptly after the flood by removing dead or yellow leaves to restore photosynthetic function. After drainage, apply sufficient amounts of quick-acting nitrogen fertilizers, in combination with phosphorus, potassium, and micronutrients. Depending on the situation, consider spraying plant growth regulators and foliar fertilizers to enhance nutrient supply and promote plant growth. Timely tilling and weeding should be performed to break up soil compaction and improve aeration.

4. Control of Pests and Diseases

Waterlogged conditions increase humidity within the corn field, which, combined with plant wounds, makes the crop more susceptible to diseases. Close monitoring is needed, particularly for bacterial diseases, brown spot disease, and leaf spot disease. Early detection and control are essential. Adding brassinolide to the fertilization program can improve plant resistance and enhance the effectiveness of pest and disease control. The rainy and hot weather can also encourage pest outbreaks, particularly the fall armyworm and corn borer. Use appropriate pesticides and spray again in 7-10 days, depending on the severity of the infestation.

5. Replanting or Changing Crops to Minimize Losses

For fields with severe flooding but not total crop loss, consider changing the corn to silage. For fields that have suffered severe damage or total loss, prepare disaster relief seeds in advance and, depending on the situation, replant with shorter-growing crops to minimize losses.