Review and Perspectives of the Use of Alginate as a Polymer Matrix for Microorganisms Applied in Agro-Industry

Alginate is a polysaccharide with the property of forming hydrogels, which is economic production, zero toxicity, and biocompatibility. In the agro-industry, alginate is used as a super absorbent polymer, coating seeds, fruits, and vegetables and as a carrier of bacteria and fungi as plant-growth promoters and biocontrol. The latter has a high impact on agriculture since the implementation of microorganisms in a polymer matrix improves soil quality; plant nutrition, and is functional as a preventive measure for the appearance of phytopathogenic. Additionally, it minimizes losses of foods due to wrong post-harvest handling. In this review, we provide an overview of physicochemical properties of alginate, some methods for preparation and modification of capsules and coatings, to finally describe its application in agro-industry as a matrix of plant-growth-promoting microorganisms, its effectiveness in cultivation and post-harvest, and its effect on the environment, as well as the prospects for future agro-industrial applications.

Microclimatic Evaluation of Five Types of Colombian Greenhouses Using Geostatistical Techniques

In Colombia, the second-largest exporter of cut flowers worldwide and one of the South American countries with the largest area of crops under cover, passive or naturally ventilated greenhouses predominate. Locally, there are several types of greenhouses that differ in architecture, size, height, shape of roof and ventilation surfaces, of which many characteristics of the microclimate generated in their interior environment are unknown. This generates productive limitations that in some way may be limiting the yield, quality and health of the final products harvested; in addition, Colombian producers do not have the ability to monitor the microclimate of their farms, much less to correlate microclimate data with data on crop production and yield. Therefore, there is a need for the Colombian grower to know the most relevant microclimate characteristics generated in the main greenhouses used locally. The objective of this work was to carry out a microclimatic characterization of the five most used types of greenhouses in Colombia. The main results allowed determining that in these structures, there are conditions of high humidity and low vapor pressure for several hours of the day, which affects the physiological processes of growth and development of the plants. It was also identified that for each type of greenhouse, depending on the level of radiation, there is a significant microclimatic heterogeneity that may be the cause of the heterogeneity in plant growth, which is a common characteristic observed by the technical cultivation personnel. Therefore, it can be concluded that it is urgent to propose microclimatic optimization strategies to help ensure the sustainability of the most important production systems in the country.

Manejo biológico del tamo de arroz bajo diferentes relaciones C:N empleando co-inóculos microbianos y promotores de crecimiento vegetal

El tamo de arroz es uno de los residuos agrícolas lignocelulósicos más abundantes en el planeta, luego de los residuos producidos por los cultivos de maíz y trigo, con una producción mundial estimada de 1000 millones de toneladas según estadísticas de la FAO. En el contexto de la agricultura moderna es determinante lograr un manejo ambientalmente sostenible de este recurso mediante su incorporación al suelo, de tal forma que se logre el reciclaje de nutrientes, evitando la incorporación de patógenos al sistema y la inmovilización de elementos como el nitrógeno por la comunidad microbiana. El objetivo de este trabajo consistió en la evaluación de un inoculo microbiano mixto a partir de productos comerciales basados en hongos del género Trichoderma y bacterias aerobias formadoras de endosporas, con potencial degradador del tamo de arroz, así como el empleo de bacterias promotoras de crecimiento vegetal al momento de la siembra, que pudieran aprovechar los nutrientes del proceso de descomposición del tamo de arroz, potenciando su actividad biológica. Los tratamientos fueron evaluados bajo diferentes relaciones C:N del tamo de arroz que favorecieran el proceso de degradación, mediante la adición de nitrógeno inorgánico. Los resultados del trabajo permitieron identificar que la aplicación de una enmienda de nitrógeno a una relación C:N 35 más una dosis adicional de urea al momento de la siembra de las semillas de arroz, fue el tratamiento más adecuado para potenciar el efecto de los microorganismos e incrementar las variables agronómicas obtenidas mediante un esquema de fertilización convencional del cultivo.