Use of Soil Microorganisms as a Biotechnological Strategy to Enhance Avocado (Persea americana)-Plant Phosphate Uptake and Growth Uso de Microorganismos del Suelo como Estrategia Biotecnológica para Mejorar la Absorción de Fósforo y el Crecimiento de Plantas de Aguacate (Persea americana)

In recent years the area cultivated with avocado has increased significantly in Colombia and this trend is expected to continue in the coming years. However, most of the soils in the highlands of the Colombian Andean, that have been used to grow avocado, are strongly acidic and nutrient deficient, particularly phosphorus (P). To alleviate these problems, high rates of lime and P fertilizers are frequently applied, in many cases the applied dose are excessive. This increases production costs, produces plant nutrient imbalance in the plant, and increases the risk of polluting surface waters. A biotechnological alternative is the combined use of phosphate solubilizing microorganisms (PSM) and arbuscular mycorhizal fungi (AMF). This work describes a series of experiments carried out to isolate, characterize, and evaluate the effectiveness of AMF and PSM in increasing plant growth and P uptake of avocado plants. The results indicate that the mycorrhizal association is an effective alternative that can easily be established in the crops; however, the excessive use of P fertilizer in these soils may limit the benefits of these fungi on avocado plants. Currently, effective PSM of avocado rhizosphere have not been detected. In some cases, these microorganisms are absent in the avocado rhizosphere and in other cases their low capacity to solubilize P discourage their use in the crop.