Technical Recommendations for Field Management of Early Rice in Southern China at the Middle and Late Stages, issued by the Ministry of Agriculture in 2015

Website news  Currently, early rice in southern China has entered the middle and late stages of field growth, with the South China region entering the grain-filling stage and the middle and lower reaches of the Yangtze River entering the jointing and booting stage. In response to the current population growth and climate characteristics of early rice, the Rice Expert Steering Group of the Ministry of Agriculture and the National Agricultural Technology Extension Service Center jointly consulted and put forward technical recommendations for field management of early rice in southern China at the middle and late stages.

First, apply fertilizer reasonably to promote growth. Fertilizer should be applied according to local conditions and seedling conditions to promote early tillering and rapid growth. For third-class seedlings that were sown and transplanted late, an additional fertilizer to preserve tillers should be applied to promote balanced growth. For first- and second-class seedlings, the focus should be on applying spike-grain fertilizer, mainly flower-preserving fertilizer, applied at the stage of the second leaf from the top to prevent degeneration of spikelets, extend the length of the top two leaves, and promote tillering into panicles. For fields with a relatively small population, fertilizer can be applied earlier when the third leaf from the top emerges, combining flower promotion with flower preservation. According to the growth of the rice plants in the field, nitrogen fertilizer and potassium fertilizer should be applied in a timely manner to increase the number of effective panicles and grains per panicle. Generally, 3-5 kg of nitrogen fertilizer and 3-5 kg of potassium fertilizer are applied per mu. If the leaf color is light green at the heading stage, grain fertilizer needs to be supplemented. Generally, 1-2 kg of nitrogen fertilizer per mu is applied, or 200 g of monopotassium phosphate plus 250 g of urea diluted in water is applied as a foliar topdressing to enhance photosynthetic capacity in the late stage and promote grain filling and seed setting.

Second, manage water scientifically to build the population. Overall, it is necessary to ensure water for panicle development in the middle growth stage and alternate dry and wet conditions in the late stage to plump the grains. In case of heavy rainfall, drainage and field exposure should be carried out promptly. For late-developing fields that have not yet been sun-dried, the principle of “when the time comes, do not wait for the seedlings” should be adhered to, and water and seedling growth should be controlled in a timely manner to prevent reluctance to drain water and reduce seedlings, which can cause an overly large population. For rice fields where sun-drying has been completed, alternating wet and dry intermittent irrigation should be adopted after rewatering to promote root growth. During the heading stage, shallow-water irrigation should be adopted to ensure heading with water, which is conducive to uniform heading and consistent maturity. After heading, alternating wet and dry intermittent irrigation should be adopted, and water should be cut off about 5 days before harvest. Water must not be cut off too early, so as to prevent premature aging and high-temperature forced ripening.

⟦NL> Third, implement integrated control of pests and diseases. Affected by last year's warm winter, the field base of pests and diseases and the population of overseas rice planthoppers were relatively large, and pests and diseases in the middle and late stages of early rice may occur more severely. The focus should be on the control of the migratory “two pests” (rice planthopper and rice leaf roller) and the “two diseases” (rice blast and rice sheath blight). Vigorously promote centralized, contiguous unified prevention and control to improve control effectiveness and reduce pesticide dosage. Strengthen pest and disease monitoring, appropriately increase the number of investigations according to weather changes, grasp the occurrence of pests and diseases, and promptly report pest and disease information, application timing, pesticide selection, and dosage. A key control operation should generally be carried out at the breakage stage of early rice to ensure that no major pests or diseases occur in the field at the middle and late stages.

Fourth, harvest at the right time to secure a bumper harvest. Harvesting early rice too early affects yield and quality, while harvesting too late affects the arrangement of the next crop. The harvest period is generally about 25 days after full heading, when the entire panicle has lost its green color and 90% of the glumes have turned yellow. The harvest period of early rice in southern China is often accompanied by adverse weather such as high temperatures and heavy rain, which can easily cause sprouting of the panicles and lead to reduced yield and lower quality. Farmers should be guided to harvest at the right time, prevent “cutting green,” and ensure full maturity. Vigorously promote mechanized combine harvesting and threshing with straw crushing devices to improve harvest efficiency and ensure that every grain is brought into the granary. (Rice Expert Steering Group of the Ministry of Agriculture, National Agricultural Technology Extension Service Center)