Rice "Three Controls" Fertilization: Frequently Asked Questions
The rice “Three Controls” fertilization technology targets prominent problems in current rice production such as excessive application of chemical fertilizers and pesticides, low and unstable yields, low fertilizer use efficiency, and serious environmental pollution. It is a high-efficiency, safe fertilization and supporting technical system featuring fertilizer control, seedling control, and pest and disease control (abbreviated as the Three Controls). Advantages: First, high and stable yields, increased production and income. Yields generally increase by about 10%, lodging is greatly reduced, stress resistance is strong, and yield stability is good, with income increasing and expenditures saved by more than 100 yuan per mu. Second, it saves fertilizer and pesticides, and is safe and environmentally friendly. It saves 10%-30% of nitrogen fertilizer, raises nitrogen fertilizer use efficiency by 10 percentage points, and significantly reduces non-point source pollution. Pests and diseases are reduced, and pesticides can be applied 1-3 fewer times, which is beneficial to the food safety of rice. Third, it is simple, practical, and widely adaptable. The technology is simple to operate; as long as farmers follow the technical regulations, they can obtain stable increases in yield and income. It can be applied under different varieties, different soils, and different climatic conditions, with stable results. Yields generally increase by about 10%, fertilizer, pesticide, labor, and other costs are saved by more than 30 yuan per mu, and income increases and expenditures are saved by more than 100 yuan per mu. Lodging is significantly reduced, pests and diseases are reduced, and yield stability is significantly improved. The technical points are as follows:
1. Total nitrogen fertilizer control: Determine the total nitrogen application rate according to the target yield and the yield of a no-nitrogen blank plot. Based on the yield of the blank plot, 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 according to 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 the heading stage, and make appropriate adjustments according to leaf color before topdressing. The biggest feature of this technology is greatly reducing tillering fertilizer and reducing ineffective tillering, while ensuring the number of panicles and focusing on large 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 application rates of phosphorus and potassium fertilizers 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 the tillering stage and half at the initial stage of panicle differentiation.
Other supporting technologies: ① Reasonable close planting to ensure the basic number of seedlings. Transplant or throw 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 field drying to control ineffective tillering. But do not dry the field too severely. ③ Pest and disease control. In rice fields using the “Three Controls” fertilization technology, damage from sheath blight, rice leaf roller, rice planthopper, and other pests and diseases is relatively light, and 1-3 fewer pesticide applications may be made as appropriate. Other practices are the same as existing conventional technologies.
Precautions: Reasonable close planting to ensure the basic number of seedlings. If density and basic seedling number do not meet the requirements, apply tillering fertilizer earlier and appropriately increase the nitrogen application rate. For soils with poor water and fertilizer retention capacity, or where density and basic seedling number do not meet the requirements, apply an additional 3-5 kg of urea 5-7 days after transplanting. If the preceding crop is vegetables or green manure, the fertilization rate should be appropriately reduced.