Mowing and fertilization can optimize the transfer and storage of systemic nutrients during the growing season by interfering with the physiological process of nutrient reabsorption in alfalfa. This study was to investigate the differences in nutrient reabsorption in alfalfa leaves and find the balance point of plant nutrient balance. The experiment set up five fertilization gradients （CK， F1， F2， F3， F4） under different mowing （3 times a year and 4 times a year， denoted as M1 and M2） and fertilization （P₂O₅ and K₂O ratio of 3∶5） conditions on alfalfa leaves. The carbon， nitrogen， and phosphorus contents of mature and senescent leaves were measured， and the characteristics of nitrogen and phosphorus reabsorption efficiency were analyzed. The results showed that mowing and fertilization significantly increased the nitrogen and phosphorus content in leaves （P<0.05）. The overall carbon to nitrogen ratio and carbon to phosphorus ratio in leaves showed a decreasing trend， while the nitrogen to phosphorus ratio showed a trend of first increasing and then decreasing， both of which were greater than 16. The nitrogen and phosphorus reabsorption efficiencies in leaves were 25.08%-42.79% and 29.05%-44.30%， respectively. The nitrogen and phosphorus reabsorption efficiency was significantly positively correlated with the carbon， nitrogen， and phosphorus content of new leaves. Mowing promoted nitrogen and phosphorus reabsorption， while fertilization first promoted and then inhibited it. M2F2 had the highest carbon and nitrogen content in mature leaves and nitrogen and phosphorus reabsorption efficiency in senescent leaves， making the best nutrient acquisition strategy for alfalfa.

Mature leaves  /  Senescent leaves  /  Mowing  /  Apply fertilizer  /  Stoichiometric characteristics  /  Nitrogen phosphorus reabsorption