1. What nutrients are essential for rice throughout its growth cycle?
Rice relies on the leaves, sheaths, and stems of the plant to absorb light, heat, and carbon dioxide, while the roots take up water and various nutrients to synthesize organic matter. These nutrients consist of a variety of elements, including macronutrients, micronutrients, and special elements. The major elements include carbon, oxygen, hydrogen, nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur. Micronutrients such as iron, manganese, and molybdenum are also important, while silicon is considered a special element. In total, rice requires 16 essential nutrients for healthy growth.
2. What are the fundamental principles governing nutrient absorption in rice?
The absorption and utilization of nutrients by rice follow two key principles. First, the law of diminishing returns: when nutrients are applied beyond a certain threshold, the yield may actually decrease. This is most noticeable with nitrogen, followed by phosphate fertilizer. Second, the principle of irreplaceability: each nutrient has a specific role in the plant’s development and cannot be substituted. Even if one nutrient is lacking, it can become a limiting factor that hinders productivity.
3. Why is organic fertilizer emphasized in rice cultivation?
Organic fertilizers are rich in organic matter, which decomposes into humus, providing a balanced supply of nutrients over time. They have long-lasting effects, improve soil structure, enhance water retention, and promote better root development. However, in recent years, the use of organic fertilizer in northern rice regions has declined, leading to poor soil conditions. Fields with low organic content suffer from poor water retention, compaction, and weak root systems, resulting in reduced yields. Therefore, supplementing with organic fertilizer is crucial for maintaining soil fertility and maximizing production.
4. What are the physiological effects of nitrogen, phosphorus, and potassium on rice, and what are the symptoms of deficiency or excess?
Nitrogen is vital for chlorophyll formation and protein synthesis, promoting leaf and root development. A deficiency leads to yellow-green leaves, narrow foliage, and stunted growth. Excess nitrogen causes excessive tillering and weak, drooping leaves. Phosphorus supports root growth, grain filling, and starch synthesis. Deficiency results in dark green, narrow leaves and poor tillering. Excessive phosphorus can cause zinc deficiency, reducing yield. Potassium improves root vitality, delays leaf aging, and enhances disease resistance. A lack of potassium leads to brown spots on leaves, weak stalks, and poor grain filling. Excess potassium generally has no significant impact but may not increase yield.
5. What are the required amounts of nitrogen, phosphorus, and potassium for producing 500 kg of rice?
For hybrid rice, approximately 13 kg of nitrogen, 7.5 kg of phosphate, and 21 kg of potash are needed. For conventional rice, the requirement is slightly higher: 15 kg of nitrogen, 8.5 kg of phosphate, and 22 kg of potash. The ideal ratio of N:P:K is 2:1:3.
6. How can the efficiency of nitrogen and phosphate fertilizers be improved in paddy fields?
To boost nitrogen use efficiency, apply base fertilizer deeply, which can increase utilization by 10-15%. For phosphate, concentrated application methods—such as dipping seedlings’ roots, applying before transplanting, or incorporating with green manure—can significantly improve uptake. These techniques help reduce losses and ensure better nutrient availability to the plants.
7. Why is potassium important in paddy fields, and what types of potassium fertilizers are available?
Paddy fields require large amounts of potassium, which is often deficient in many soils. Applying potassium fertilizer can significantly boost rice yield. Common types of potassium fertilizers include potassium chloride (KCl), potassium sulfate (Kâ‚‚SOâ‚„), and wood ash. Each has different properties and is suitable for various soil conditions.
8. What are the common fertilization practices in rice-growing areas today?
Rice fertilization typically involves two main stages: base fertilizer and top dressing. Base fertilizer is applied before transplanting, often combined with organic manure. Top dressing includes applications like green manure, tiller fertilizer, panicle fertilizer, and grain fertilizer. These methods ensure a steady supply of nutrients throughout the growing season.
9. Why is layered or deep fertilization emphasized in rice farming?
Deep application of chemical fertilizers, especially in the reducing layer, increases nutrient stability and utilization. Studies show that deep application of ammonium bicarbonate can boost yield by 13-19% compared to surface application. It reduces nitrogen loss through volatilization and leaching, enhances root absorption, and provides long-term benefits. This method ensures consistent nutrient supply, improves seed setting, and increases grain weight, making it an efficient approach for high-yield rice production.
10. How should base fertilizer and tiller fertilizer be applied?
Base fertilizer should be applied in three stages to optimize nutrient use and promote tillering. The first application occurs 5-7 days after transplanting, using about 5.5 kg of ammonium sulfate along with some superphosphate and zinc sulfate. A second application follows every 10-20 days, and the final dose should be applied 5-10 days before the end of the tillering phase to balance growth and support healthy development.
Welding Bolt, a kind of fastener consisting of head and Screw (cylinder with external thread), needs to be matched with nut to fasten and connect two parts with through hole. This type of connection is called bolt connection. If the nut is unscrewed from the bolt, the two parts can be separated, so the bolt connection is detachable.
Welding Bolt,Weld Bolt,Welded Eye Bolt,Welded Screws
Jiangsu Jiajie Special Screw Co., Ltd , https://www.jiajiescrewcompany.com