NUTRIENT CONTENTS IN DIFFERENT ORGANS OF Acacia mangium, NORTHEAST VIETNAM

Nitrogen (N), phosphate (P), and potassium (K) are major nutrients for the plant. Their concentrations in plant's organs are different, which are mainly influenced by genetic factors and environmental conditions. Understanding the nutrient contents is important for maximizing production and biomass accumulation of plantation. This work aimed at investigating the nutrient contents in different organs (leaves, barks, branches, roots, and stems) and leaf types (young, old, shed, and dry-dead leaves) of Acacia mangium in Northeast Vietnam. The samples were collected in an 18-month-old plantation in early spring. The results indicated that young leaves contained 89% water, while old leaves contained 78%. N, P, and K were significantly different among organs and leaf types. Among organs, the highest N (1.20%), P (0.99%), and K (1.45%) contents were recorded in leaves, while lowest contents (< 0.30%) were found in stems. Among leaf types, the highest N (1.80%), P (0.97%), and K (1.53%) were recorded in young leaves, while lowest contents (< 0.76%) were found in shed leaves. The N (1.12%), P (0.47%), and K (0.43%) contents in dry-dead leaves were higher than that in old and shed leaves. It is concluded that during senescence nutrients in leaves are re-translocated to other organs for optimizing nutrient use. While nutrient re-translocation is not processed in dead leaves by diseases. Low P content may indicate nutrient-inefficient soil and P application should be conducted to increase the production of A. mangium plantation.