FERTILIZATION EFFECTS ON EUCALYPTUS PELLITA F. MUELL PRODUCTIVITY IN THE COLOMBIAN ORINOCO REGION

ABSTRACT The Orinoco region, is the one with the largest area for forest development. Nonetheless, some of its soils are acid and characterized by low fertility levels, which has considerably limited plantation productivity. Therefore, this study aimed at assessing the effects of soil fertilizing and liming by using phosphorus and potassium on 34-month-old Eucalyptus pellita productivity. Tests have been carried out at: Villanueva, Casanare; Puerto Lopez, Meta and La Primavera, Vichada, under a random block design with a factor arrangement of 3x3x3, equivalent to: 0, 1 and 3 Mg ha-1 of dolomitic lime (LIME); 30, 75 and 120 kg ha-1 of P (P2O5) as well as 60, 120 and 180 kg ha-1 of K (K2O). Timber productivity volume was assessed 34 months after planting, obtaining significant differences. In Puerto Lopez, LIME effect on E. pellita growth followed a simple linear model, whereas a logarithmic behavior was observed in La Primavera and Villanueva. P2O5 effect (p<0.01) on timber volume was observed only in La Primavera, following a square-root model. K2O did not have a significant effect (p>0.05) on E. pellita growth. The results obtained indicate the positive effect on E. pellita growth in the three areas of study by using doses of approximately 1 Mg ha-1 of lime; and 120 kg ha-1 of P2O5 in La Primavera.

摘要 奥里诺科（Orinoco）地区是森林开发面积最大的区域。然而其部分土壤呈酸性且肥力水平低下，极大制约了人工林的生产力。为此，本研究旨在评估施用磷、钾肥与石灰对34月龄佩利塔桉（Eucalyptus pellita）生产力的影响。试验分别在卡萨纳雷省比利亚努埃瓦（Villanueva, Casanare）、梅塔省洛佩斯港（Puerto Lopez, Meta）与维查达省拉普里马韦拉（La Primavera, Vichada）开展，采用随机区组设计（random block design），因子组合为3×3×3，具体设置如下：白云质石灰（dolomitic lime，LIME）施用量分别为0、1、3 Mg·ha⁻¹；五氧化二磷（P₂O₅）施用量分别为30、75、120 kg·ha⁻¹；氧化钾（K₂O）施用量分别为60、120、180 kg·ha⁻¹。于种植后34个月测定木材生产力材积，结果显示各组间存在显著差异。在洛佩斯港，白云质石灰对佩利塔桉生长的影响符合简单线性模型；而在拉普里马韦拉与比利亚努埃瓦，其影响则呈现对数响应特征。五氧化二磷施用量对材积的影响（p<0.01）仅在拉普里马韦拉地区显著，符合平方根模型。氧化钾施用量对佩利塔桉生长无显著影响（p>0.05）。本研究结果表明，在三个试验区域中，施用约1 Mg·ha⁻¹的白云质石灰，以及在拉普里马韦拉地区施用120 kg·ha⁻¹的五氧化二磷，均可对佩利塔桉生长产生积极促进作用。