Effects of Combined Application of super water-absorbent polymer and special fertilizers on the growth, physiology and biochemistry of Eucalyptus cloeziana

Using Eucalyptus cloeziana seedlings as experimental materials, a two-factor randomized block design was employed to assess four dosage levels of super water-absorbent polymer and four eucalyptus-specific fertilizer on the seedling growth, physiological traits and biochemical characteristics. The results showed that: The main effects of super water-absorbent polymer, special fertilizer dosage and their interactions had highly significant effects on seedling height, diameter growth, leaf nutrient content, leaf nutrient stoichiometric ratios(N/P, N/K), photosynthetic characteristics and antioxidant enzymes activity. The combination of super water-absorbent polymer and fertilizer promoted seedling height, diameter and total biomass, with the highest values observed under the W₂M₂ treatment, which were 2.23, 1.85 and 1.20 times of the control, respectively. Under the W₂M₃ treatment, leaf total nitrogen and phosphorus contents were the highest. and leaf N/P rations were higher than the control across all treatments. However, K/P ratios were below 3.4, indicating potassium limitation, while N limitation showed a tendency to diminish compared to the control. The combination of super water-absorbent polymer and special fertilizer significantly improved the photosynthetic capacity and antioxidant enzyme activities of seedlings. Affiliation function analysis showed that the seedling growth, physiological and biochemical conditions were optimal under the W₂M₂ treatment. In conclusion, the combination of 5 g/plant of super water-absorbent polymer and 100 g/plant of specialized fertilizer is most beneficial for promoting the growth of Eucalyptus cloeziana seedlings.