Movimiento y tensión del agua a través de la relación suelo-planta en árboles de Eucalyptus pellita F. Muell. bajo tres esquemas de fertilización con fósforo, potasio y calcio en Puerto López, Meta

Abstract

Eucalyptus wood production in the Orinoquía Colombiana is mainly limited by water scarcity and soil fertility where this activity takes place. The water deficit produces a decrease in the photosynthetic capacity of plants, generating in turn metabolic changes that limit the assimilation of nutrients. Low soil fertility forces fertilizer addition. The movement of water in the soil was studied through the measurement of infiltration and unsaturated hydraulic conductivity, as well as water tension through the moisture retention curve. In the plant, the sap flow, foliar water potential (PHF), perspiration (E), photosynthesis rate (A) and stomatal conductance (gs) in Eucalyptus pellita F. Muell trees were subjected to schemes of differential fertilization with calcium contributions with dolomite lime, potassium with potassium chloride and phosphorus with triple super phosphate in the municipality of Puerto López - Departamento del Meta (Colombia). A data analysis was carried out using a randomized complete block experimental design with a 3x3x3 factorial arrangement in order to explain the behavior of the effect of the sources and the fertilizer doses on the variables of PHF, E, A and gs . The results suggest that the maximum average foliar water potential (20.83 Bar) was influenced by the application of dolomite lime in a dose of 1 t/ha of lime; while the average value with the highest photosynthetic rate (11.70 mol CO2 m-2 s-1) is given by a dose of 0 t/ha of dolomite lime, 30 kg / ha of triple super phosphate and 180 kg / ha of potassium chloride (Ca0P30K180). With respect to stomatal conductance, its highest value (555.55 mmol H2O m-2 s-1) was obtained for the Ca0P75K120 treatment. The mean value of the highest perspiration (5.46 mmol H2O m-2 s-1) was observed by effect only of K180. Also, the highest flow of sap (0.49 cm/h) in the stem corresponded to the treatment of 1 t/ha of dolomite lime, 120 kg/ha of triple super phosphate and no application of potassium chloride. Finally, the interaction of phosphorus and potassium applications was definitive for the photosynthetic rate and stomatal conductance. While the perspiration rate was related only to the application of potassium. On the other hand, the higher photosynthetic rate is related to sectors with higher volumetric humidity and lower resistance to penetration.