DRY-MATTER PRODUCTION IN ACACIA-MANGIUM PLANTS UNDER DIFFERENT LEVELSOF FERTILIZATION

A nursery essay was carried out in La Canada de Urdaneta, Venezuela to evaluate the effect of different levels of fertilization on dry matte r production of Acacia mangium plants. The treatments applied were: 45 , 30 and 20 and 90, 60 and 40 mg/plant of NPK, respectively; 45, 30, 2 0 and 1 mg/plant of NPK + Mo, 45, 30, 20 and 4 000 mg/plant of NPK + C a, 45 and 30 mg/plant of NP, 45 and 20 mg/plant of NK, 30 and 20 mg/pl ant of PK, 45 mg N/plant, 30 mg P/plant, 20 mg K/plant and the control . A completely randomized design was used. The indexes were dry weight s of leaves, stem s' roots leaf:stem dry weights ratio and the ratio o f the dry weight of the aerial and radicular part. Fertilization signi ficantly affected (P < 0.01) leaf dry weight and the treatment of 90, 60 and 40 mg/plant of NPK shaved the highest value (2.97 g/plant). Fer tilization had a significant effect (P < 0.01) on stem dry weight, bei ng the highest weight (0.67 g/plant) the application of 45, 30 and 20 mg/plant of NPK + Mo. Root dry weight was affected (P < 0.01) by ferti lization, and the highest value was with 30 and 20 mg/plant of PK (2.8 5 g/plant). The ratio leaf :stem dry weights was significantly affecte d by the treatments (P < 0.01), that of 30 and 20 mg/plant of PK produ ced the highest ratio (6.50). The treatments significantly(P < 0.01) a ffected the aerial :root dry weight ratio and the highest was with 45 and 30 mg/plant of N and P (3.06). These results show that the lack of nutrients reduced growth indicators and vigour of plants and the grow th of the aerial radicular system on transplanting. Studies on the dep ressive effect of Ca in the presence of N, P and K on growth are warra nted.