Study on dry matter accumulation and nutrient absorption and distribution of nitrogen，phosphorus and potassium in cigar eggplant core

<bold>Objective</bold> In order to realize the scientific and reasonable nutrient supply of cigar core varieties and improve the yield and quality of cigar leaves，the dry matter accumulation，nitrogen（N），phosphorus（P），potassium（K）absorption accumulation and distribution law of each part during the growth of cigar plants were investigated. <bold>Method</bold> The cigar core variety Yunxue 39 was chosen as the research material.Field experiments were conducted to study the accumulation of dry and fresh weight and the nutrient absorption rules of N，P and K in six key growth periods：transplanting period，root extension period，thriving period，lower leaf harvesting period，middle leaf harvesting period and upper leaf harvesting period.Dry and fresh weight，nutrient content of N，P and K in each part of the tobacco plant were measured and calculated. <bold>Result</bold> During the whole growth period，the nutrient accumulation of N，P and K were 4.92 g/plant，0.46 g/plant and 5.43 g/plant，respectively.The dry and fresh weight were 184.61 g/plant and 1 013.63 g/plant，respectively.The accumulation of fresh weight of whole plant，roots，stems and leaves accounted for 36.68%，41.26%，38.61% and 34.06% of the total weight for the whole growth period，and the accumulation of dry weight of whole plant，roots，stems and leaves accounted for 38.63%，41.87%，40.65% and 35.62% of the total weight for the whole growth period，respectively.It is the period of the fastest accumulation of dry and fresh weight in each part of the tobacco plant.N，P and K absorbed by plants were mainly distributed in leaves during the whole growth period，and the proportion was the highest in the flourishing period，reaching 85.35%，77.37% and 79.16% of the total accumulation of the whole plant，respectively.The N，P and K nutrients absorbed by cigar in the final harvest stage of parietal leaves accounted for 37.74%，38.23% and 36.18% of the total absorbed amount in the whole growth stage，respectively. <bold>Conclusion</bold> The accumulation of fresh weight and dry weight and the absorption of different nutrients in cigar plants were in line with Logistic curve.The absorption ranking of N，P and K nutrients in cigar plants during the whole growth period was K&gt;N&gt;P，and the fastest period of fresh，dry weight and nutrient absorption and accumulation was between prosperous period and mature harvesting period.The dry and fresh weight and nutrient accumulation in different parts were leaf，stem and root in order from the largest to the smallest.When the yield of fresh tobacco leaves reaches the level of 3 645.75 kg/hm²，N 3.04 kg，P₂O₅ 0.28 kg and K₂O 3.35 kg need to be absorbed in every 100 kg of cigar dry tobacco leaves，and the ratio is 1∶0.09∶1.1.