1 Sorghum's fertilizer requirement

   The test data shows that for every 100kg of sorghum grain produced, it is necessary to absorb 2.6kg of nitrogen (n), 1.36kg of phosphorus (p) and 3.06kg of potassium (k). The ratio of nitrogen, phosphorus and potassium is 10.51.2. From the perspective of the whole sorghum growth and development process, the sorghum fertilizer requirement rule is less in the early period and more in the middle period.

2 Formula fertilization model of sorghum

   The application of trace element fertilizers (such as zn fertilizers) under the condition that organic fertilizers, nitrogen, phosphorus, and potassium fertilizers are satisfied, has a special effect on the sorghum yield and quality improvement. Therefore, according to the abundance of soil content, the appropriate amount of micro-fertilizer can be applied in the early stage of crop growth.

   The production of 100 kg of sorghum grain requires nitrogen 3.25 ± 1.37 kg, phosphorus 1.68 ± 0.48 kg, and potassium 4.54 ± 1.14 kg. The ratio of the three is 1: 0.52: 1.37. Among them, from emergence to jointing, the absorbed nitrogen accounted for 12.4% of the nitrogen requirement for the entire growth period, phosphorus accounted for 6.5%, and potassium accounted for 7.5%; during the jointing to flowering period, the absorbed nitrogen accounted for 62.5% of the nitrogen requirement for the entire growth period It accounted for 2.9% and potassium accounted for 65.4%; from flowering to maturity, the absorbed nitrogen accounted for 25.1% of the nitrogen requirement during the entire growth period, phosphorus accounted for 40.6%, and potassium accounted for 27.1%.

3 Fertilization technology of sorghum

   Base fertilizer: The application rate of base fertilizer is generally 30-60 tons of organic fertilizer per hectare. For low-fertility phosphorus-deficient plots, 300-500 kg of superphosphate should be applied.

   Fertilizer: Ammonium sulfate is safer in commonly used chemical fertilizers. 100-150 kg per hectare is appropriate. If nitrogen and phosphorus compound fertilizer is used as seed fertilizer, it is convenient and effective, and diammonium phosphate is commonly used, with a dosage of 150 kg per hectare.

   Topdressing: The topdressing period is mainly the jointing period and the flag-picking period, but the topdressing is generally performed once in production, and the topdressing period is more effective. The amount of top dressing is generally 300-450 kg urea per hectare.