The use in agriculture of diverse plastic elements, such as bags, covers, hoses, between others, and the inappropriate destruction, translates into environmental and visual pollution of the Colombian field. The present manuscript presents an analysis of the main uses of these products, of their useful life, of its positive or negative bio-degradability and its potential environmental cost, based on recommendations of its management, described in the literature, field observations and suggestions of ways to dispose of this "rubbish", once the elements comply with its purpose. Also, an analysis of a possible replacement of the "plastic" by other elements, less polluting, but potentially usable for the purposes are included in the interest of the agricultural fruit production, soil protection, weed management, between other agronomic practices. We conclude that despite the wide acceptance of the plasticulture technology this is not based on indigenous research that proves its benefits, but in adopting foreign knowledge. Substantial research activity is however being performed in the country in search of biodegradable polymers that could replace the synthetic ones.

Durante 30 meses, se realizó un estudio en la localidad de Firavitoba, Boyacá, con el objetivo de evaluar y de analizar los cambios en el dosel y la capacidad de adaptación de tres especies forestales de clima frío, Alnus acuminata, Escallonia pendula y Quercus humboldtii, en un suelo degradado por erosión hídrica. Las tres especies fueron sembradas en dos arreglos espaciales, tres bolillos y rectángulo y dentro de esos arreglos, se ubicaron diferentes tratamientos de mezclas simples y combinadas. Se midieron parámetros, como altura de planta, emisión foliar, índice de área foliar, diámetro de la copa y producción de hojarasca. Se observó que A. acuminata es una planta de gran sensibilidad al estrés hídrico, al presentar altas pérdidas de material por sequía, mientras que E. pendula mostró los mayores índices de sobrevivencia. Sin embargo, A. acuminata es la especie que obtuvo mayores índices de elongación, mayor tasa de emisión foliar y un crecimiento sostenido del IAF, aun cuando presenta periodos de defoliación masiva. Q. humboldtii demostró ser una especie que requiere sombra durante los primeros 24 meses después del transplante, pues al sembrarla individualmente, las plantas crecieron de forma lenta y desarrollaron pocas estructuras foliares. Las tres especies mejoraron las condiciones nutricionales del suelo, debido al aporte de hojarasca. El experimento estableció las condiciones de siembra para las tres especies y concluye quepueden ser usadas, preferiblemente, en mezcla, para programas de reforestación de suelos, con altos niveles de degradación física.

A research was carried out in order to estimate a leaf area model for blue berry (Vaccinium corymbosum) in high altitude tropical conditions, using linear measurements such as lamina length (L), width (W) and the length-width product (LxW) by stepwise regression analysis. Leaves from Sharp Blue and Biloxi cultivars were used to develop the model in the localities of Sibaté and Firavitoba. The calibration step was developed with plants coming from Sibaté, with 180 observations and the models validation was effectuated at Firavitoba. Six models were obtained, three linear and three polynomial of second order, for each genetic material. The selection model forms were, LA = 0.638(LW), R 2 0.94, and LA = 0.0075(LW) 2 +0.3321(LW)+2.2104, R 2 0.94. These models were validated by measuring new leaf samples taken from different plant levels (low, medium and superior) of, only, the cultivar Sharp Blue. The models of Biloxi presented very low R 2 and high CME. The models produced in this study can be used reliably for estimating the individual leaf area coming from different levels of the vegetal canopy of the blueberry cv Sharp Blue, and also, estimate the total plant leaf area, without destructive method. They are not recommendable for the Biloxi cultivar.