1. According to the characteristics of the fertilizer, the fertilizers suitable for external application are used as fertilizers with good external fertilization effects: urea, potassium dihydrogen phosphate, potassium nitrate, potassium sulfate, ammonium sulfate, zinc sulfate, ferrous sulfate, Calcium phosphate, ammonium metaphosphate, grass ash leachate, and most trace element fertilizers. Some highly volatile fertilizers such as ammonia, ammonium bicarbonate and fertilizers containing chloride ions such as ammonium chloride, potassium chloride, etc., are not suitable for external fertilization because they cause large fertilizer losses, while others are crops. Have an adverse effect.
Second, according to the crop type and growth period, the optimum concentration of fertiliser dosage and concentration outside the root fertilization is generally: urea 1-2%; potassium dihydrogen phosphate 0.3-0.5%; superphosphate calcium leaching solution 3-5%; molybdenum Ammonium acid 0.01-0.1%; ammonium metaphosphate 2-3%; borax 0.1-0.2%; zinc sulfate spray concentration is generally 0.05% to 0.1%; ferrous sulfate concentration is generally 0.2% to 1%; fertilizer per 667m2 The amount of liquid is 50-60kg. For dicotyledonous crops such as cotton, the leaf area is large, and the nutrients in the solution are easily absorbed. Therefore, the concentration of the spray fertilizer for such crops should be appropriately lower; the leaf area of ​​monocotyledonous crops such as rice is relatively small, and the degree of siliceousness of the leaves is high. The nutrients are difficult to be quickly absorbed by the leaves, so the fertilizer concentration must be appropriately increased during the spraying.
Third, according to climatic conditions, choose the appropriate time for spraying fertilizer. The best choice for external fertilization is when the air is wet or dew in the morning and evening. The windless cloudy day can be sprayed all day, but the best effect is applied in the evening.
4. According to the mobility of fertilizer in crops, determine the number of fertilizers. The mobility of nitrogen and potassium fertilizers in crops is very strong. Therefore, it can be sprayed once in the critical period of crop growth; the mobility of phosphate fertilizer is inferior to nitrogen. Potassium fertilizer should be sprayed 1-2 times according to the growth condition of the crop; zinc, molybdenum, manganese, copper, iron fertilizer and non-moving boron, calcium and other micro-fertilizers that are only partially moved in the crop body should be sprayed continuously. -3 times.
5. According to the biological characteristics of the crop, choose the best spray site. The green stems and leaves of crops are reasonable parts of spray fertilizer. When the cotyledon crops are sprayed, they should be sprayed evenly on the front and back of the leaves. The monocotyledonous crops only need to spray the fertilizer from the top to the bottom of the leaves.
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ABS Plastic Steel Tape Measure
ABS Plastic Steel Tape Measure
Shell made of ABS material, black rubber, can protect it from falling damage, durable, buckle and sling design, easy to carry, handheld and portable. Just pull the tape to lock the size in place. Perfect for daily use, travel, camping, etc.
It is suitable for kitchens, garages, manufacturing factories, steel factories, hardware stores, etc. it can be used to measure the length and width of measuring tools or casting aircraft, machines, furniture, etc., and it can be used to measure the accurate large tape.
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