(2) Dynamics of nutrient absorption in different growth stages of Panax notoginseng: The changes of total nitrogen and total potassium in different growth stages of Panax notoginseng are complicated. The total nitrogen content of annual and biennial plants basically showed a downward trend before 65,438+10, and it showed an upward trend after 65,438+10. Three-year-old children had a peak absorption in August, and it has been declining since then. The total potassium content of annual plants showed a downward trend in a year. biennial plants and triennial plants absorbed more potassium from April to June, and after June, the absorption in biennial plants decreased, and the change of triennial plants was not obvious. The change trend of total phosphorus content of Panax notoginseng in different years is consistent, which decreases from April to June and begins to increase after August.
From the absolute amount of three elements absorbed, August 1 day and 10 day are two peak periods of fertilizer absorption, and the absorption of nitrogen and potassium accounts for 73.29% and 45.05% of the total fertilizer absorption in the whole growth period, while the absorption of phosphorus is the most on 12 day, accounting for 52.83% of the total fertilizer absorption. The fertilizer requirement of two-year-old Panax notoginseng is the largest in flowering and fruiting period, and the absorption of nitrogen, phosphorus, potassium and phosphorus accounts for 50.84%, 63. 14% and 65.43% of the total absorption in the whole growth period respectively. Therefore, August (flowering period) to 10 (fruiting period) should be the most important fertilizer requirement period for Panax notoginseng.