Zinc is one of the necessary trace elements in rice growth and development. Zinc deficiency in rice shows obvious symptoms. Zinc is deficient in zinc, first appeared in the middle lobe of the lower leaf, chlorotic yellow and white spots, reddish-brown spots and irregular plaques on the upper part, then gradually expanded into reddish-brown stripe spots, turned reddish-brown dry from the tip of the leaf, and from the lower leaves The up leaves appear one by one. The diseased plants had slow leaf emergence, the new leaves were short and narrow, and the leaf color was light, especially yellowish-white faded near the base midline. Severely ill plant leaf shortening or misalignment, obvious dwarf clumping, very few tillers, often uneven performance in the field. Roots are old and brown. The application of zinc fertilizer in zinc-deficient paddy fields has a significant effect of increasing yield and improving quality. However, the scientific application of zinc fertilizer is very strong. Unreasonable application not only wastes fertilizer but may also lead to a reduction in production. Therefore, the application of zinc fertilizer in paddy field must master the following technical requirements: Can only be applied in zinc-deficient rice fields. The critical indicator of available zinc in the soil suitable for rice growth is 0.5 mg/kg. Below this criterion, the application of zinc fertilizer is effective. Generally calcareous soil is rich in calcium, high PH value, effective zinc is easy to combine with carbonate or hydroxide to produce zinc carbonate or zinc hydroxide precipitation and become invalid, it is often lack of zinc; rice field with strong reduction effect is easy Zinc deficiency; long-term large-scale application of nitrogen, phosphorus fertilizer rice, effective zinc will also be reduced. Zinc fertilizer should be added to the above types of paddy fields. 2. Appropriate application. Most of the zinc fertilizer used in paddy fields is zinc sulfate, which is generally 1 to 1.5 kg per acre. Due to the obvious aftereffect of zinc fertilizer, the zinc fertilizer applied in the first season still has an effect on increasing rice production in the next season. Therefore, zinc fertilizer does not have to be applied annually, and it is usually applied two to three years. 3. Zinc fertilizer should be applied early. Putian zinc fertilizer, high utilization, good effect. Both basic and spraying. It is best to apply zinc fertilizer in Daejeon when it is in Putian. 4. Application should be uniform. In order to spread the zinc fertilizer evenly, the zinc fertilizer can be mixed with the physiological acid fertilizer. However, zinc fertilizers should not be mixed with phosphate fertilizers to prevent the formation of zinc phosphate, which is hard to absorb and reduce the fertilizer efficiency. 5. Foliar spraying concentration should be appropriate. Applying zinc fertilizer as a foliar fertilizer is the main method of topdressing, and a suitable concentration is 0.1% to 0.2% of zinc sulfate solution. Putian should be sprayed at the 3 leaf stage of seedlings and 3 to 5 days before transplanting. Daejeon should spray the seedlings 10 to 15 days after the seedlings are transplanted or transplanted. It is better to spray 2 to 3 times continuously.
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