Technical Guidelines for Southern Double-Cropping Late Rice Production

Currently, southern double-cropping late rice is gradually being transplanted. Affected by earlier low temperatures and rainy weather, the harvest of early rice has been delayed by 5–7 days on average, affecting the timely transplantation of late rice. According to meteorological forecasts, this year’s weather conditions are expected to be generally unfavorable, with low temperatures, frequent rains in the autumn, and potential “cold dew wind,” which are detrimental to the safe heading and maturity of late rice. Additionally, pests and diseases are predicted to occur more severely. Addressing these challenges and risks, the Rice Expert Guidance Group of the Ministry of Agriculture and Rural Affairs, together with the National Agricultural Technology Extension Service Center, has proposed technical guidelines for southern double-cropping late rice production with the focus on “speeding up field preparation, promoting early growth, strengthening field management, and preventing pests, diseases, and low temperatures.”

1. Ensure Timely Transplantation and Adequate Seedlings

Currently, late rice varieties are predominantly thermosensitive indica rice with limited flexibility in seedling age. Transplanting aged seedlings may result in stunted growth, especially for mechanically transplanted rice seedlings. For late rice seedlings with prolonged seedling age or rapid growth, regulate growth through water control and the application of chemical growth retardants. For fields where early rice harvest has been delayed, expedite field preparation and transplantation while adopting higher planting density to compensate for the delay and ensure adequate panicle numbers. For fields where the growing period of early rice has been excessively prolonged, early harvesting should be carried out to ensure timely transplantation of late rice. For areas where seedlings have been destroyed by floods and timely transplantation is not possible, consider planting coarse cereals, legumes, root crops, or fast-growing vegetables to avoid leaving fields fallow.

2. Apply Fertilizers Scientifically to Promote Spikelet Formation

Delayed transplantation may lead to seedling aging and reduced tillering ability. Apply tillering fertilizers early and increase the proportion of basal and tillering fertilizers to about 75% of the total fertilizer amount. Apply 5–7 kg of urea per mu within 3–5 days after transplantation to promote rapid early growth. For panicle fertilizers, apply 2–3 kg of urea and potassium chloride per mu during the second-to-last leaf emergence and the tip emergence of the last leaf to enhance robust stems and large panicles. For fields with smaller plant populations, apply 2–3 kg of urea per mu at the full heading stage or apply 1.5–2 kg of urea along with 150–200 g of potassium dihydrogen phosphate via foliar spraying to promote grain filling and maturity.

3. Manage Water Scientifically to Prevent Lodging

Maintain shallow water levels in the fields to promote tillering within 15 days after transplantation. For fields with seedling broadcasting, irrigate with “flower water” to stabilize seedlings, then adopt wet management with periodic exposure of the field to encourage tillering and root development. Conduct timely field drying to control seedling growth. For fields with low fertility and weak seedlings, apply light drying; for high-fertility fields with strong seedlings, apply more intense drying. For fields with tillage and seedling broadcasting, apply earlier and heavier drying; for no-tillage seedling broadcasting fields with relatively delayed seedling establishment, apply more frequent but lighter drying. After drying, promptly restore water and adopt alternating irrigation to promote root development and enhance plant resistance to lodging.

4. Proactively Prevent Pests and Diseases

Focus on controlling major migratory and epidemic pests and diseases such as rice planthoppers, rice leafrollers, rice blast, and sheath blight. For rice planthoppers, “suppress early and control later” using appropriate pesticides during the young nymph peak. For rice leafrollers, prioritize protecting functional leaves during the mid-to-late stages of rice growth. For rice blast and false smut, focus on preventive measures during the heading and flowering stages. For sheath blight, target prevention during the tillering and jointing stages, opting for high-concentration single-component agents to improve control efficiency.

5. Mitigate Autumn Cold and Promote Early Maturity

Given the high likelihood of low temperatures, rainy weather, and “cold dew wind” in southern rice regions this year, early preparations are essential. For fields where heading has not yet occurred by the arrival of “cold dew wind,” irrigate with deep water to protect the “embryo.” For fields approaching heading just before “cold dew wind,” apply foliar sprays of potassium dihydrogen phosphate to accelerate heading. For fields at the heading and flowering stages during the onset of “cold dew wind,” irrigate with deep water for warmth and, where conditions permit, apply warming agents to enhance cold resistance, mitigating low-temperature damage and ensuring safe heading.