Resumo

MARIN, Nilson; PLAZA, Guido  e  ROJAS, Jesús. Technical and economical assessment of fertilization alternatives and corrective measures in flue-cured tobacco (Nicotiana tabacum) in the García Rovira region, Santander (Colombia). Agron. colomb. [online]. 2008, vol.26, n.3, pp.505-516. ISSN 0120-9965.

The principle problems observed in soil fertility of the García Rovira region are degradation and chemical disbalance. In the soil of this region, both the pH and Ca (3,5-5,0 meq·100g-1) show high levels, which restrain P, Mg and micronutrient availability for Flue-cured tobacco. The objective of this work is to guide the fertilizer management and corrective measurements that enhance efficiency, nutrient availability and uptake. Six treatments were established, namely conventional fertilization + kieserite (T1), conventional fertilization + kieserite + phosphoric acid (T2), acid reaction fertilization + kieserite (T3), organic-mineral fertilization + kieserite (T4), conventional fertilization + kieserite + covering (T5), conventional-control fertilization (T6). The experimental design was randomized complete block with three replicates. Two groups of variables were analyzed: edaphic 45 days after transplanting and those of production at harvest. The T2 achieved the highest pH reduction of 7,3 to 7,0, the largest increase in available P and received the highest yield level, 18.47% more than controls, without affecting the first-quality leaf quantity. The T3 reduced pH and increased Mg content in a lower proportion than T2. It showed the second highest yield without affecting first-quality leaf quantity and showed more profitablty followed by T2. The T1 and T5 treatments had a better yield than those of the controls. Nonetheless, the profit obtained in the harvest does not justify the fertilization cost increment. The T4 had a lower production than that of the control in yield, average price and total harvest cost.

Palavras-chave : fertilization management; pH; nutritional availability; tobacco nutrients absorption.

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