How to Prevent Cold Damage in Rice? Detailed Explanation of Fertilization Measures

Fertilization case: In 2006, in rice-growing areas such as Shangzhi City, Heilongjiang Province, during the early stage of rice growth, some rice seedlings encountered low-temperature weather below 17°C, and rice cold damage problems of varying degrees occurred. In the rice-growing areas of Ningxia and Zhangjiakou, Hebei in the northwest region, in autumn during the late stage of rice growth, just at the grain-filling stage, the temperature suddenly dropped below 20°C, causing rice to suffer cold damage, which was very unfavorable for grain filling, and the seed-setting rate decreased by 10-20%, with severe cases decreasing by more than 50%.

Expert comments: In northern rice-growing areas, in order to defend against the cold damage problems brought to rice production by low-temperature weather, in addition to paying attention to variety selection and strengthening cold-protection measures in farmland management, it is also necessary to pay attention to cultivating strong seedlings and improving the cold resistance of rice plants, which is conducive to high and stable rice yields. In order to defend against rice cold damage, the following techniques should be adopted in fertilization measures:

1. Control the application rate and application period of nitrogen fertilizer. In the early stage of rice growth, excessive nitrogen fertilizer application will accelerate rice growth, resulting in tender stems and leaves with high water content, making them susceptible to cold and not cold-resistant, so the amount of nitrogen fertilizer should be controlled in the early stage, and the nitrogen application period should be moved later. In northern rice-growing areas in years with cold damage, the total amount of nitrogen fertilizer should usually be reduced by 20-30%. In terms of fertilization timing, base fertilizer should account for 40-50%, tillering fertilizer should be applied at 10-15% depending on temperature, and topdressing should be applied 1-2 times before and after heading.

2. Increase the application of phosphorus and potassium fertilizers. Phosphorus and potassium fertilizers can improve the cold resistance of rice and promote early maturity, so phosphorus and potassium fertilizers should be increased. The application method should be divided into two layers with deep and shallow combination, applying base fertilizer deeply and topdressing shallowly, so that phosphorus fertilizer is distributed throughout the entire plow layer, which can not only improve the cold resistance of seedlings, but also prevent phosphorus deficiency during later grain filling and improve the seed-setting rate. Potassium fertilizer can be applied once as base fertilizer, or part of it can be applied again as topdressing, which is more conducive to making the rice plants robust and improving cold resistance and disease resistance.

3. Attach importance to the application of organic fertilizer. Applying decomposed organic fertilizer to rice fields is conducive to preserving the temperature of the root-layer soil and promoting the development of the rice root system, forming strong seedlings and improving the cold resistance and disease resistance of rice plants. Among organic fertilizers, if plant ash is applied or straw is returned to the field, it is not only conducive to soil layer temperature preservation, but can also supply potassium nutrition, which is conducive to making the rice plants robust and improving the stress resistance of rice.

Case tips: The fertilization measures for defending against rice cold damage are mainly to attach importance to the application of organic fertilizer, control the application rate of nitrogen fertilizer and the nitrogen application period; increase the application of phosphorus and potassium fertilizers, cultivate strong seedlings, and improve the stress resistance of rice.