Reduce the percentage of empty grains in the summer-autumn rice crop.

In rice production, one of the issues that farmers are currently very concerned about is the relatively high percentage of empty grains in the summer-autumn crop. This is also one of the factors that greatly affects rice yield and efficiency. In reality, even if we apply good measures to increase rice yield, if the rice field has a high percentage of empty grains, all efforts become meaningless. Rice yield can be severely reduced due to empty grains.

There are many reasons for empty grains in the summer-autumn rice crop, but lodging is the main and most significant cause. The percentage of empty grains varies depending on when the rice plants are lodged during different growth stages. If the lodging occurs before or immediately after flowering, the percentage of empty grains is very high, and rice yield will decrease significantly. Furthermore, hiring laborers to harvest lodged rice is more difficult and expensive compared to standing rice, leading to increased production costs.

The causes of empty rice grains are:

- Due to the application of inappropriate technical factors by producers, such as sowing at too high a density, unbalanced fertilization between nitrogen, phosphorus, and potassium, mainly excessive nitrogen fertilization in the later stages, the rice plants develop leaves too vigorously, weakening the stems and leading to lodging. The rice panicles are submerged in water, preventing pollination and resulting in empty grains.

- Due to the impact of external factors such as heavy rain and strong winds, if rice plants are in bloom and encounter a storm, the percentage of empty grains will be very high. Extremely hot or cold weather, or cloudy skies without sunshine, also impair pollination, leading to empty grains.

- Due to variety: Some rice varieties, such as IR64 and Jasmin85, tend to have a high percentage of empty grains in the summer-autumn crop. Others, such as OM1490 and OM2517, tend to have a low percentage of empty grains. Tall rice varieties are more prone to lodging in the summer-autumn crop, increasing the percentage of empty grains.

- Due to pests and diseases: During the rice flowering stage, rice plants are often affected by pests and diseases such as leaf-rolling caterpillars, leaf blast, and neck blast. Rice fields severely damaged by these pests and diseases will result in a large number of empty grains.

By understanding the causes of empty grains in rice plants, we can develop effective solutions to proactively reduce the percentage of empty grains, thereby maintaining yield.

Specific measures to reduce falls include:

+ Use rice varieties with strong stems: In the summer-autumn season, most high-yielding, short-duration rice varieties have strong straw, such as OM1490, CS2000, OM2517... Fragrant rice varieties, long-duration rice varieties, and seasonal rice varieties usually have tall stems and weak straw.

+ Appropriate planting schedule: In the Mekong Delta, the summer-autumn crop season, particularly in October and November, often experiences heavy and prolonged rainfall and flooding. Therefore, it is necessary to arrange the planting season appropriately to harvest before the floods arrive.

+ Thoroughly prepare the soil before sowing to encourage strong root development, which will help the rice plants become more robust.

+ Applying sparse sowing methods such as sowing in rows, with a seed rate of 100-120 kg/rice/ha to ensure good aeration in the rice field, will reduce pests and diseases.
+ It is necessary to apply a balanced amount of nitrogen, phosphorus, and potassium fertilizers. Nitrogen fertilizer should be applied according to the leaf color chart to meet the growth needs of the rice plant without wasting fertilizer. Note that applying potassium fertilizer will make the rice plant stronger.

+ Regularly inspect the fields, and when pests or diseases reach a damaging level, treat them immediately. Before and after rice flowering, spray Till Supfer to control some diseases and increase grain fertility and give the rice a bright, glossy color.

+ Regulating water in rice fields: Ideally, drain the water from the field before the rice plants enter the tillering stage. This creates aeration in the field and allows the roots to develop and penetrate deeper into the soil. Drain the water for about 7 days, then reintroduce water and maintain the water level at 5-10cm until the rice ripens. Drain all water 10 days before harvesting.

According to (Online Agricultural Market) - LY