A Detailed Guide to the Latest Standardized Fertilization Methods for Rice
Fertilization Principles
1. Implement balanced fertilization. According to the nutrient requirements of each crop, the soil nutrient supply status and the fertilizer effect, determine the corresponding fertilization amount and fertilization method. Based on the principle of combining organic fertilizer with inorganic fertilizer and combining base fertilizer with topdressing, achieve balanced fertilization.
2. Implement harmless treatment of organic fertilizer. Organic fertilizer produced and used by farmers themselves must undergo decomposition and fermentation, and harmless treatment to kill pathogenic microorganisms, insect eggs and weed seeds. It is prohibited to use industrial waste, municipal garbage and sludge, and farmyard manure that does not meet harmless treatment standards.
3. Implement compound and specialized inorganic fertilizers. The selected fertilizer types should conform to the fertilizer varieties and quality requirements specified in fertilizer quality standards, and organic-inorganic compound fertilizers and compound fertilizers specialized for various crops should be selected as much as possible.
Standardized Fertilization Techniques for Rice
Fertilization should emphasize heavy application of base fertilizer, early topdressing of tillering fertilizer, skillful use of beneficial fertilizer, and supplemental application of grain fertilizer. The fertilization amount is based on nitrogen fertilizer, and the nitrogen-phosphorus-potassium ratio method is used to determine the amounts of phosphorus and potassium fertilizers. Apply 225-300 kg of urea per hectare. After determining the nitrogen fertilizer amount, determine the amounts of phosphorus and potassium fertilizers according to nitrogen:phosphorus:potassium = 1:0.5:0.3-0.5.
1. Seedbed soil preparation. For each square meter of seedbed soil, apply 10-15 kg of high-quality decomposed farmyard manure and 0.125 kg of strong seedling nutrient agent, and mix evenly with the prepared sieved seedbed soil. The seedbed soil thickness should be about 10 cm, and the pH value should be 4.5-5.5.
2. Seedbed topdressing. When nutrient deficiency is found at the 2.5-leaf stage of the seedlings, use 1.5 g-2 g of ammonium sulfate and 0.25 g of zinc sulfate per square meter, dilute 100 times with water, and spray on the leaf surface. After spraying, promptly rinse the leaf surface with clean water. Six days before lifting the seedlings, broadcast 150 g of diammonium phosphate per square meter, and after topdressing spray clean water to wash the seedlings.
3. Fertilization in the main field. Increase the application of farmyard manure and reduce the application of chemical fertilizers. Apply 30 tonnes of decomposed organic fertilizer per hectare, incorporated in combination with dry harrowing; apply 112.5-150 kg of diammonium phosphate and 75 kg of potassium sulfate per hectare, incorporated into the whole layer in combination with water-land preparation.
4. Topdressing. The principles of rice topdressing: sufficient tillering fertilizer, steady panicle fertilizer, and grain fertilizer as needed.
Tillering fertilizer: from after transplanting to before tillering, apply 50-75 kg of urea per hectare.
Panicle fertilizer: apply at the early jointing stage, 50-75 kg of urea and 50-75 kg of potassium sulfate per hectare. Increasing potassium fertilizer can improve the seed-setting rate and 1000-grain weight, promote early maturity, and enhance disease resistance and lodging resistance.
Grain fertilizer: apply before heading, 15-22.5 kg of urea per hectare. Although nitrogen uptake decreases after heading, if soil nitrogen supply is insufficient, the photosynthetic efficiency of leaves will be reduced. An appropriate amount of grain fertilizer topdressing can prevent premature senescence of roots and leaves.
Foliar topdressing: if zinc fertilizer was not applied as base fertilizer, 50-100 g of zinc sulfate can be prepared into a 0.2% aqueous solution for foliar supplementation at the tillering stage. Liquid fertilizers containing silicon and selenium can be sprayed on the leaves to enhance rice disease resistance, promote early maturity, improve the eating quality and nutritional quality of rice, and increase commercial value. Spraying liquid fertilizers such as 0.2%-0.3% potassium dihydrogen phosphate at the full heading to grain-filling stage can extend the survival rate of functional leaves in the late growth period, accelerate the grain-filling speed, reduce the empty grain rate, increase the 1000-grain weight, and have a certain effect on preventing delayed-type cold damage.
Four Precautions for Rice Fertilization
First, pay attention to applying sufficient organic fertilizer. Organic fertilizer contains various nutrients, can improve soil aeration and fertilizer and water retention characteristics, promote steady growth of rice plants, and achieve high yield and high quality. Organic fertilizer is mainly used as base fertilizer. Apply 30-40 dan of decomposed farmyard manure per mu, or 30-40 kg of cake fertilizer, and after ploughing and before flooding, apply 40-50 dan of human and livestock manure.
Second, pay attention to controlling nitrogen fertilizer. Excessive application of nitrogen fertilizer to rice will not only cause an increase in ineffective tillers, turning green, lodging, and intensified pests and diseases, leading to more empty grains, a decreased seed-setting rate, and affecting rice yield. Nitrogen fertilizer is mainly used as topdressing. The first time, after rice transplanting, apply 6-7 kg of urea per mu; the second time, 13-15 days after transplanting, combined with field weeding, apply 4-5 kg of urea per mu to promote tillering and strong tillers. In the middle stage, pay attention to drainage and fertilizer control, and only supplement some balanced fertilizer as appropriate for the poorer-growing second- and third-class seedlings. In the later stage, supplement 3-4 kg of grain fertilizer as appropriate according to the seedlings.
Third, pay attention to the application of phosphorus and potassium fertilizers. Phosphorus and potassium fertilizers can enhance plant vitality, promote nutrient synthesis and transport, strengthen photosynthesis, extend the functional period of leaves, make grains plump and full, and increase yield. Phosphorus fertilizer is suitable as base fertilizer, while potassium fertilizer is better as topdressing. In fields with sufficient organic fertilizer, apply 20-40 kg of phosphorus fertilizer per mu as base fertilizer, and before tillering, 3.5-5 kg of potassium chloride per mu can be topdressed. Spraying Huaguo Doctor Guoneng Multi-element in the later stage of rice can promote grain filling and seed setting. Spray once each at the late heading and flowering stage and at the grain-filling stage, using 50-100 g of phosphorus and potassium fertilizer each time per mu, mixed with 50-60 kg of water, and spray in the evening.
Fourth, pay attention to increasing the application of trace element fertilizers. Zinc fertilizer and silicon fertilizer can not only improve the oxygen supply to rice roots, enhance the stress resistance and lodging resistance of rice plants, improve plant disease resistance, promote root development in the later stage, extend the leaf functional period, and prevent premature senescence; they can also accelerate flower development, increase pollen quantity, promote flower grain germination, and help increase the panicle-forming rate of rice; moreover, they can promote larger panicles and more grains, improve the seed-setting rate and grain plumpness, and increase rice yield.
In optimized formula fertilization for rice, people often attach great importance to the combined application of macronutrient fertilizers such as nitrogen, phosphorus and potassium, but neglect the application of elements such as silicon and zinc.
In fact, rice is a crop that absorbs relatively large amounts of silicon. Generally, stems and leaves contain 10-20% silicon dioxide. The silicic acid content in rice plants is about 10 times that of nitrogen and about 20 times that of phosphorus. Silicon deficiency in rice can easily lead to slender and weak stems, easy lodging and susceptibility to disease. Silicon deficiency in the early stage reduces the number of panicles formed by rice, while silicon deficiency in the later stage reduces the number of spikelets, so the high quality and high yield of rice cannot be guaranteed. Applying silicon fertilizer to rice can enhance rice resistance to pests and diseases and lodging, improve plant type, increase light energy utilization, reduce leaf transpiration water loss, and improve water use efficiency. It can generally increase yield by more than 10% and can also improve rice quality. Especially in newly converted paddy fields, cold waterlogged fields and acidic soils, the effect of applying silicon fertilizer to rice is more obvious.
Rice is very sensitive to the zinc element. Zinc deficiency will cause plants to produce leaves slowly, new leaves to be short and narrow, leaf color to be relatively pale, especially near the midrib at the base fading to yellowish white. Severe cases show obvious dwarfing and clustering of plants, very few tillers, and the field often appears uneven. Rice roots become old and decayed, brown in color, and at the heading stage show "flowering but no harvest." Yield is generally reduced by 10-30%, and in severe fields it may even destroy the seedlings and result in no harvest. Large-area experimental results show that after reasonable zinc application, rice plant height, effective tiller number, grains per panicle, and 1000-grain weight all increase, the empty grain rate decreases to some extent, and yield can generally be increased by more than 15%. Especially in acidic soils, calcareous soils, cold waterlogged fields and newly converted paddy fields, the effect of applying zinc fertilizer is more obvious.
1. Application of silicon fertilizer: silicate containing calcium and magnesium is mostly used as silicon fertilizer, mixed with other fertilizers when applying base fertilizer, with an application rate of 1 kg of effective silicon per mu.
2. Application of zinc fertilizer: it is generally advocated for use as base fertilizer, applying 1 kg of zinc sulfate per mu (1 mu = 1/15 ha), mixed with other chemical fertilizers; it can also be used for foliar application, soil topdressing in the middle and later stages, and seed treatment. The commonly used concentration for foliar topdressing is 0.3% zinc sulfate solution. For later-stage topdressing, about 500 g of zinc sulfate is applied. Both are carried out after zinc deficiency symptoms appear or at the late tillering stage. For seed treatment, soak rice seeds in 0.1% zinc sulfate solution for 24 hours.