Detailed Explanation of Key Technical Points for Late-Stage Management of Rice in the Main Field

I. Water-Saving Irrigation Techniques

During the rice growth period, water-saving techniques should be adopted for irrigation, with irrigation and drainage carried out according to the water requirements and characteristics of rice at each growth stage. These are mainly divided into deep-water greening, shallow-water tillering, deep-water booting and heading, and shallow-water ripening. During the greening stage, because the roots of the seedlings are damaged during transplanting and absorb little water while leaf transpiration is high, deep-water greening must be applied after transplanting to prevent physiological water loss, with a water depth of about 2-3 cm being appropriate. If the irrigation water is too deep, nutrient decomposition is slow, which is unfavorable for tillering; the booting and heading stage is the period of the greatest water demand in the entire life of rice, especially during the meiosis stage, when it is even more sensitive to water. Water shortage at this time will lead to degeneration of spikelets, resulting in short panicles, few grains, and many empty shells. Therefore, a 2 cm water layer should be maintained in the field during the booting and heading stage.

II. Measures to Prevent Low-Temperature Cold Damage

When rice encounters periodic low temperatures, it also encounters continuous fine rain. Pollen absorbs water and easily ruptures, increasing empty shells. If an early frost occurs in early September, rice cannot carry out normal grain filling and milk ripening. When wind speed is too high, it causes direct damage to rice organs and increases empty and blighted grains, directly affecting the seed-setting rate of rice and causing yield reduction.

Prevention methods:

1. Select excellent varieties with strong stress resistance, cultivate strong seedlings, increase the application of silicon fertilizer, increase leaf toughness, promote root development, prevent leaves from drooping, reduce shading, and create a good light-receiving environment. Improve stress resistance.

2. During the heading stage of rice, pay attention to weather changes. When the temperature is below 17°C, deepen the water layer to 15-17 cm to keep warm with water. After the temperature rises, restore the original water layer to facilitate normal ripening of rice.

3. Without affecting yield, appropriately reduce the application rate of nitrogen fertilizer and increase the application of potassium fertilizer. Starting from the flower-promoting fertilizer, apply once at the same leaf age each time, which can enhance the ability of rice plants to absorb potassium fertilizer, reduce side effects, increase panicle size and grain weight. Increase rice yield.

III. Timely Harvest

The timing of harvest will directly affect the appearance quality, eating quality, and yield of rice. If harvested too early, the grains are not yet fully mature, there are many blighted and green grains, the milling rate is low, and the rice quality is poor; if harvested too late, nutrients in the grains flow back, yield decreases, and it is prone to early frost damage, stem lodging, thick rice husks, and dull, lusterless rice quality, causing direct economic losses. Therefore, failure to harvest at the proper time has a great impact on yield. When the rachis is dry and yellow at the top and bottom, two-thirds of the branches on the upper part of the panicle have turned yellow, and the grains on the lower part of the panicle have set shape and become hard, this is the best harvest period.