What are the key points of the "three controls" fertilization technique for rice?
Rice is a species of the herbaceous genus Oryza, and also the most important and longest-cultivated species in the genus Oryza used as a food crop. It originated in China, and rice was already cultivated in China's Yangtze River basin seven thousand years ago. So, what are the key points of the "three controls" fertilization technique for rice?
1. Technical overview
The "three controls" fertilization technique for rice is a new fertilization technique that achieves high and stable yields, saves costs and increases efficiency, is environmentally friendly, and enhances rice safety. This technique combines soil testing with seedling testing, coordinating the relationship between high yield and high efficiency, safety, and environmental protection. It has three major advantages: First, high and stable yields, increasing both yield and income. Generally increases yield by 5%-10%, greatly reduces lodging, has strong stress resistance, and good yield stability. Second, it saves fertilizer and pesticides, and is safe and environmentally friendly. It saves about 20% of nitrogen fertilizer, increases nitrogen fertilizer use efficiency by 10 percentage points, reduces non-point source nitrogen pollution, reduces pests and diseases, and can reduce pesticide application by 1-3 times, which is beneficial for rice food safety. Third, it is simple and practical, with wide adaptability. As long as farmers follow the technical procedures, they can achieve stable yield and income increases, and the number of fertilization applications is generally reduced. It can be applied under different varieties, different soils, and different climate conditions, with stable effects. It can be applied under different varieties, different soils, and different climate conditions, with stable effects. Generally increases yield by about 10%, saves more than 30 yuan per mu in fertilizer, pesticide, labor, and other costs, and increases income and saves expenses by more than 100 yuan per mu. Lodging is significantly reduced, pests and diseases are reduced, and yield stability is significantly improved.
2. Key technical points
1. Total nitrogen fertilizer control: Determine the total nitrogen application rate based on the target yield and the yield of a no-nitrogen blank plot. Based on the blank plot yield, apply about 5 kg of nitrogen for every 100 kg increase in rice grain yield. The blank plot yield can be determined through experiments or estimated through surveys. The target yield is determined based on conditions such as variety, soil, and climate.
2. Staged regulation of nitrogen fertilizer: After the total nitrogen application rate is determined, determine the nitrogen application rate for each stage according to the proportions of about 40% for basal fertilizer, about 20% at mid-tillering stage (about 15 days after transplanting), about 30% at the initial stage of young panicle differentiation, and 5%-10% at heading stage, and make appropriate adjustments based on leaf color before topdressing. The biggest feature of this technique is greatly reducing tillering fertilizer and reducing ineffective tillering, focusing on large panicles while ensuring the number of panicles.
3. Application of phosphorus and potassium fertilizers: Based on the yield of the no-fertilizer blank plot, for every 100 kg increase in rice grain yield, an additional 2-3 kg of phosphorus fertilizer (calculated as P2O5) and 4-5 kg of potassium fertilizer (calculated as K2O) are needed. When blank plot yield data are lacking, the phosphorus and potassium fertilizer application rates can be determined according to the ratio N:P2O5:K2O=1:(0.2-0.4):(0.8-1). All phosphorus fertilizer is applied as basal fertilizer, and potassium fertilizer is applied half at tillering stage and half at the initial stage of panicle differentiation.
4. Other supporting techniques: (1) Reasonable dense planting to ensure the basic number of seedlings. Transplant or broadcast about 18,000 hills per mu, with the basic number of seedlings reaching 30,000 seedlings for hybrid rice and 60,000 seedlings for conventional rice.
(2) Timely seedling control. When the number of stems and tillers reaches 80% of the target number of panicles, begin draining the field to control ineffective tillering. But do not drain the field too heavily.
(3) Prevention and control of pests and diseases. In rice fields using the "three controls" fertilization technique, damage from diseases and pests such as sheath blight, rice leaf roller, and rice planthopper is relatively light, and pesticide application can be reduced by 1-3 times as appropriate. Other aspects are the same as existing conventional techniques.
Precautions: Reasonable dense planting to ensure the basic number of seedlings. If the density and basic number of seedlings do not meet the requirements, then tillering fertilizer should be applied earlier and the nitrogen application rate should be appropriately increased. For soils with poor water and fertilizer retention capacity, or where density and basic number of seedlings do not meet the requirements, 3-5 kg of urea should be additionally applied 5-7 days after transplanting. If the previous crop is vegetables or green manure, the fertilization rate should be appropriately reduced.