Resumen Las micorrizas son asociaciones entre plantas y hongos benéficos y se consideran los componentes más activos de los órganos de absorción de nutrientes de la planta. Por otro lado, los microorganismos del suelo son pieza fundamental para su funcionamiento y dinámica como sistema vivo. El objetivo de esta investigación fue evaluar el efecto de la aplicación de hongos micorrízicos arbusculares sobre la abundancia de grupos funcionales asociados al ciclo nitrógeno de suelos cultivados con café en Sasaima, Cundinamarca, Colombia. Se recolectaron muestras de suelo durante los meses 0, 2, y 8 en cuatro parcelas de estudio, que tuvieron el siguiente manejo: Parcela 1. Aplicación de hongos micorrízicos arbusculares en suspensión, con una relación de 75-80 esporas/gramo de polvo seco; Parcela 2. Aplicación de hongos micorrízicos arbusculares en formulación sólida, 300 esporas/gramo; Parcela 3. Aplicación de hongos micorrízicos arbusculares nativos, extraídas del suelo de estudio 25 esporas/gramo; Parcela 4. Control, sin aplicación de hongos micorrízicos arbusculares. La abundancia de los microorganismos del suelo asociados al ciclo del nitrógeno se estimó mediante la técnica del número más probable para cuantificar los microorganismos amonificantes, proteolíticos, oxidantes de amonio, oxidantes de nitrito y desnitrificantes. Se midieron los parámetros fisicoquímicos estándares del suelo Y, posteriormente, se realizaron análisis univariados y multivariados de los datos. Los resultados mostraron una correlación positiva entre la aplicación de hongos micorrízicos arbusculares, el carbono orgánico y el fósforo, siendo mayor en las parcelas con aplicación de hongos micorrízicos arbusculares nativos. No obstante, la abundancia de los grupos funcionales del ciclo del nitrógeno no presentó diferencias significativas entre los tratamientos; aun así, el análisis de componentes principales mostró una correlación entre las parcelas con aplicación de hongos micorrízicos arbusculares en suspensión y sólidas, los microorganismos amonificantes y las bacterias oxidantes de amonio.

Abstract Mycorrhizae are associations between plants and beneficial fungi. They are the most active components of the plant’s nutrient absorption organs. On the other hand, soil microorganisms are fundamental for their functioning and dynamics as a living system. This research aimed to evaluate the effects of applying arbuscular mycorrhizal fungi (AMF) to the abundance of functional groups associated with the nitrogen cycle of soils with coffee plantations in Sasaima, Cundinamarca, Colombia. The soil samples were collected from four study plots during months 0, 2, and 8 and handled as follows: Plot 1. Application of liquid AMF (75-80 spores/gram of dry powder); Plot 2. Application of AMF in solid formulation (300 spores/gram); Plot 3. Application of native AMF, extracted from the soil under study (25 spores/gram); and Plot 4. Control, no application of AMF. The abundance of soil microorganisms associated with the nitrogen cycle was estimated using the most probable number technique to quantify ammonifying, proteolytic, ammonium-oxidizing, nitrite- oxidizing, and denitrifying microorganisms. The standard physicochemical parameters of the soil were measured. Afterward, univariate and multivariate analyses of the data were performed. The results showed a positive correlation between the application of AMF, organic carbon, and phosphorus, higher in the plots with native AMF. However, the abundance of functional groups of the nitrogen cycle did not show significant differences among the treatments; still, the principal components analysis showed a correlation between the plots with liquid and solid AMF, ammonifying microorganisms, and ammonium-oxidizing bacteria.

Resumen La presente investigación tuvo como objetivo evaluar cambios de la calidad del suelo asociados a la implementación de técnicas de agricultura ecológica (AE) en cafetales bajo diferentes coberturas en San José de Pare, Boyacá. Para el cumplimiento de este objetivo se determinaron cambios en parámetros fisicoquímicos, abundancia de grupos funcionales de microorganismos (solubilizadores de fosfatos, celulolíticos, fijadores de nitrógeno) y actividades enzimáticas (fosfatasa acida y alcalina, β-glucosidasa, ureasa y proteasa). Las muestras de suelo se recolectaron de manera bimensual durante un periodo de diez meses en parcelas con cultivo de café con tres diferentes coberturas: plátano, mandarina y una mezcla de cítricos. Los resultados mostraron modificaciones de los indicadores de calidad del suelo como consecuencia de la aplicación de técnicas de AE, encontrando un aumento significativo en el contenido de fósforo, carbono, bacterias y hongos solubilizadores de fosfato y hongos celulolíticos. En contraste, no se observaron cambios significativamente relevantes en la actividad enzimática.

Abstract The aim of this research was to evaluate the changes in the soil quality associated with the implementation of ecological agriculture (EA) techniques in coffee plantations under different coverings (banana, mandarin, and a mix of citrus fruits) in San José de Pare, Boyacá. To this effect, changes in physicochemical parameters, the abundance of functional groups of microorganisms (phosphate solubilizers, cellulolytic microorganisms, nitrogen fixers), and enzymatic activities (acid and alkaline phosphatase, β-glucosidase, urease, and protease) were determined. The soil samples were collected on a bimonthly basis for a period of ten months in plots cultivated with coffee plantations with three different coverings: banana, mandarin, and a mix of citrus fruits. The results showed modifications in the soil quality indicators as a consequence of the application of EA techniques, finding a significant increase in the content of phosphorus, carbon, phosphate solubilizing bacteria and fungi, and cellulolytic fungi. In contrast, no significant changes were observed for enzymatic activity.

ABSTRACT Páramos are unique strategic ecosystems in the neotropical region, above the upper limit of closed forest and below the lower limit of perpetual snow in the tropical mountains of Central and South America. Their soils are of particular importance for water regulation and carbon storage; however, thousands of peasants develop agricultural activities such as potato cultivation and livestock farming in these areas. This research aimed to evaluate the possible heavy metals contents (arsenic, cadmium, mercury, and lead) and pesticide residues (348 in total) associated with potato cultivation and livestock farming activities in soils of Páramo ecosystems (Cruz Verde and El Verjón) in Cundinamarca, Colombia. Soil samples are from areas in the Páramo under potato crops and livestock farming, at two different altitudes: 3300 m a.s.l. (meters above sea level) and 2900 m a.s.l.; and then, the physical-chemical properties, heavy metals, and pesticide content were determined in each sample. The results showed that none of the soils evaluated exceeded the concentrations of heavy metals permitted by the normativity that was analyzed. On the other hand, we found the presence of the fungicide dimethomorph (0.27 mg kg-1) in soils under potato crops at altitudes 1 and 2, fungicide metalaxyl (0.013 mg kg-1) in soils under potato crops at altitude 1, and insecticide thiamethoxam (0.048 mg kg-1) in soils under potato crops at altitude 2. Anyhow, the statistical analysis did not show significant heavy metals contents or pesticide residues in the Páramo soils associated with potato cultivation and livestock farming; nonetheless, there are significant impacts on five of the physicochemical properties of the soils under study (moisture, bulk density, organic carbon, cation exchange capacity, and phosphorus). Although soil physicochemical parameters properties were modified by soil potato crop and cattle raising, these land land-use types did not cause relevant impacts heavy metals and pesticides, which could be due to the specific agricultural practices adopted in the area (Potato-pasture rotation system, with fallow periods of between 7 and 10 years). Finally, this study represents the first report on heavy metals and pesticide residues in Páramo soils.

Resumen Los Páramos son ecosistemas neotropicales resultantes de formaciones insulares dominadas por gramíneas en matojo y matorrales que se encuentran por encima de la línea de bosque continua y por debajo de la línea de nieves perpetuas de las cumbres más altas de los Andes Septentrionales. El objetivo de esta investigación fue evaluar las hipótesis existentes sobre el impacto que el cultivo de papa y la explotación ganadera tienen en la calidad de los suelos de Páramo. Para ello, se realizaron muestreos en tres usos del suelo a dos alturas diferentes: Páramo con la menor intervención posible y Páramo donde se realizan las actividades de cultivo de papa y explotación ganadera, en los que se determinaron las propiedades fisicoquímicas, abundancia de grupos funcionales de microorganismos (fijadores de nitrógeno, solubilizadores de fosfato, celulolíticos) y actividades enzimáticas (ureasa, proteasa, p-glucosidasa, fosfatasa ácida y alcalina). La humedad gravimétrica, la densidad aparente, el carbono orgánico, la capacidad de intercambio catiónico, la ureasa, la fosfatasa ácida y la p-glucosidasa mostraron diferencias estadísticamente significativas (P < 0.05), lo cual indica que la calidad del suelo expuesto a actividades agrícolas y ganaderas está siendo modificada. Mientras que, para los microorganismos, la hipótesis no se confirmó, no obstante, existen señales de advertencia para el futuro en el caso de continuar con estas prácticas.

Abstract Páramos are Neotropical ecosystems that result from insular formations dominated by tufted hair grasses and shrubs, and are located above the continuous forest track and below the perpetual snowline of the highest peaks in the Northern Andes. The aim of this research was to check the reliability of the hypothesis that the potato cultivation and livestock farming activities modify the quality of Páramo soils. For this, soil samples were taken from soil used with three different purposes at two different heights: Páramo with the least possible intervention, and Páramo where the activities of potato cropping and livestock farming were carried out; from these, and that have been determined to have physicochemical properties, abundance of functional groups of microorganisms (nitrogen-fixing, phosphate solubilizers, cellulolytic microorganisms), and enzymatic activities (urease, protease, p-glucosidase, acid, and alkaline phosphatase). The gravimetric humidity, apparent density, organic carbon, cation exchange capacity, urease, acid phosphatase, and p-glucosidase showed statistically significant differences (P < 0.05), indicating that there is a change in the quality of the soil that is exposed to agricultural activities. As for microorganisms the hypothesis was not confirmed; there are warning signs for the future in the case of continuing with these practices, but there are no significant differences.

ABSTRACT Páramo ecosystems are of great importance because they are considered hotspots within the Tropical Andes. They are also very important for their role as producers and regulators of water processes in the Neotropic. However, the human occupation of the Colombian Páramos has generated conflict between environmental benefits and productive land uses, specifically the potato cultivation and livestock. To assess possible changes associated with potato cultivation (Solanum tuberosum L.) and livestock on the microbial communities of Páramo soils, the objective of this research was to evaluate the possible effects of potato cultivation and livestock farming on the soil microorganisms associated with different functional groups (nitrogen fixers, phosphate solubilizers and cellulolytic) in the Páramo of Nevados National Natural Park (Nevados NNP), Colombia. Samples were collected from soils under potato cultivation, livestock, and Páramo conservation areas over two climatic seasons (rainy and dry) in three farms at different elevations (3769, 3590, and 3432 m a.s.l.). The microorganisms were isolated using selective culture media for each functional group and identified using molecular markers; microbial diversity was analyzed using multivariate statistical tools. Changes were dependent on land use, elevation, and climate and were statistically significant in the rainy season on all three farms and one of the farms during the dry season. Similarly, the results indicated that climate has a greater impact on the evaluated microbial communities than land use does; the changes were significantly different between the soil under potato cultivation and in conserved Páramo sites at most of the evaluated locations and between soil subjected to livestock farming and Páramo in certain locations. However, the differences between potato cultivation and livestock farming were smaller. This study showed for the first time that the microbial structure (abundance and composition) of microorganism functional groups was different as a result of potato cultivation and livestock farming on Páramo soils, although these changes were dependent on farm elevation and climate.

RESUMO Compreender os impactos de práticas agrícolas sobre os indicadores de qualidade do solo, como atividades enzimáticas, é de grande importância para avançar no diagnóstico e no manejo sustentável. Objetivou-se avaliar o efeito dos manejos agrícolas ecológico e convencional sobre as atividades enzimáticas de um solo em agroecossistemas sob cultivo de cafeeiro. As atividades enzimáticas foram associadas aos ciclos biogeoquímicos do nitrogênio (urease e protease), fósforo (fosfatase ácida e alcalina) e carbono (β-glicosidase), durante as estações chuvosa e seca. Propriedades físico-químicas do solo também foram avaliadas e relacionadas a escores de resiliência vinculados à variabilidade climática reportada para as áreas em estudo. As atividades de urease, fosfatase alcalina e ácida e ß-glicosidase foram estatisticamente maiores nos agroecossistemas ecológicos do que nos convencionais. Isto pode ser atribuído à maior aplicação de resíduos orgânicos no manejo ecológico, bem como à ausência de pesticidas e fertilizantes sintéticos, o que possibilita melhores condições para a atividade microbiana. Os escores de resiliência à variabilidade climática que mostraram as maiores correlações com as atividades enzimáticas avaliadas foram: conhecimento dos agricultores sobre micro-organismos do solo, não uso de agrotóxicos e fertilizantes sintéticos e não dependência de insumos externos. Concluiu-se que as atividades enzimáticas são modificadas pelos sistemas de manejo, sendo especificamente favorecidas pelo manejo ecológico. Este agroecossistema, a longo prazo, assegura o uso eficiente dos recursos do solo, com menor degradação e contaminação.

ABSTRACT Understanding the impacts of agricultural practices on soil quality indicators, such as enzymatic activities, is of great importance, in order to advance in their diagnosis and sustainable management. This study aimed to evaluate the effect of ecological and conventional agricultural managements on enzymatic activities of a soil under coffee agroecosystems. The enzymatic activities were associated with the biogeochemical cycles of nitrogen (urease and protease), phosphorus (acid and alkaline phosphatase) and carbon (β-glucosidase), during the rainy and dry seasons. Physical-chemical soil proprieties were also assessed and related to resilience scores linked to the climatic variability reported for the areas under study. The activities of urease, alkaline and acid phosphatase and ß-glucosidase were statistically higher in ecological agroecosystems than in conventional ones. This may be attributed to the greater application of organic waste in the ecological environment, as well as to the absence of pesticides and synthetic fertilizers, which allow better conditions for the microbial activity. The resilience scores to the climate variability that showed the highest correlations with the assessed enzymatic activities were: the farmers' knowledge on soil microorganisms, non-use of pesticides and synthetic fertilizers and non-dependence on external supplies. It was concluded that the enzymatic activities are modified by the management systems, being specifically favored by the ecological management. This agroecosystem, in the long term, ensures an efficient use of the soil resources, with a lower degradation and contamination.

Colombia is a country biologically and culturally megadiverse. Presented inside the largest expanse of páramos of the world, which are considered the planet's water plants and habitats of high biological diversity. However, human occupation of the Colombian Páramos has generated conflict between environmental regulations and productive land uses. This article analyzes the alternative proposed solutions to the conflict between environmental authorities of protected areas and inhabitants of the Páramos in Colombia. Previously there were two types of alternatives: The first suggested granting ecotourism services in parks and land purchases by mixed companies. The second proposed the abandonment of the production activities of farmers, mediated by educational processes and in compliance with environmental standards on pain of facing punitive action by the state. We propose a third alternative, that involves community management plans with time and institutional funding, and implementation of agroecological models, biocultural rescue memory and changes in agrarian structure.

Colombia es uno de los países denominados megadiversos biológica y culturalmente. Presenta a su interior la mayor extensión de páramos del mundo, los cuales son considerados fábricas de agua del planeta y hábitats de rica diversidad biológica. Por otro lado, la ocupación humana de los páramos colombianos ha generado conflictos entre las normativas ambientales vigentes y los usos productivos del suelo. El presente artículo analiza las alternativas aplicadas ante el conflicto entre autoridades ambientales de áreas protegidas y habitantes de los páramos en Colombia. Se encontraron dos tipos de alternativas: la primera plantea la concesión de servicios ecoturísticos en los parques naturales y la compra de tierras por parte de sociedades de economía mixta. La segunda plantea el abandono de las actividades productivas de los agricultores, mediado por procesos educativos o de cumplimiento de las normas ambientales vigentes, so pena de enfrentar acciones punitivas por parte del Estado. Este trabajo presenta una tercera alternativa, que parte de la crítica a las dos anteriores e incluye diferentes estrategias: planes de manejo comunitario con tiempo y financiación institucional pertinente, aplicación de modelos agroecológicos y rescate de la memoria biocultural y cambios en la estructura agraria.

A systematized survey was conducted to find soil-borne microbes that degrade cellulose in soils from unique ecosystems, such as the Superpáramo, Páramo, and the High Andean Forest in the Nevados National Natural Park (NNNP), Colombia. These high mountain ecosystems represent extreme environments, such as high levels of solar radiation, low atmospheric pressure, and extreme daily changes in temperature. Cellulolytic activity of the microorganisms was evaluated using qualitative tests, such as growth in selective media followed by staining with congo red and iodine, and quantitative tests to determine the activity of endoglucanase, β-glucosidase, exoglucanase, and total cellulase. Microorganisms were identified using molecular markers, such as the 16S rRNA gene for bacteria and the internal transcribed spacer region (ITS) of ribosomal DNA for fungi. Multivariate statistical analysis (MVA) was used to select microorganisms with high cellulolytic capacity. A total of 108 microorganisms were isolated from the soils and, in general, the enzymatic activities of fungi were higher than those of bacteria. Our results also found that none of the organisms studied were able to degrade all the components of the cellulose and it is therefore suggested that a combination of bacteria and/or fungi with various enzymatic activities be used to obtain high total cellulolytic activity. This study gives an overview of the potential microorganism that could be used for cellulose degradation in various biotechnological applications and for sustainable agricultural waste treatment.

Se analizaron las prácticas agrícolas y condiciones de vida de la comunidad de la vereda El Bosque en el Parque Nacional los Nevados, Colombia. Se aplicaron varias herramientas como la observación participante, entrevistas semiestructuradas, líneas de tiempo, mapas por vereda, por finca, calendarios agrícolas, relojes de actividades por género y cuestionarios estructurados. Se determinó que el cultivo de papa y la ganadería se desarrollan como estrategia de supervivencia y herencia cultural paramuna, prácticas aprendidas desde la revolución verde y los saberes propios. Estas prácticas agrícolas han generado contradicciones entre la conservación del ecosistema y el mejoramiento de la calidad de vida de sus habitantes. A partir de la investigación se propone implementar planes de manejo comunitarios, modelos agroecológicos, rescate de memoria biocultural y transformaciones en la estructura agraria.

It were analyzed the agricultural practices and the living conditions of the community from the rural district El Bosque, located in Los Nevados National Park, Colombia. It were applied various tools such as participant observation, semistructured interviews, timelines, maps per rural district and farms, agricultural calendars, activity schedule by gender and structured questionnaires. It was determined that potato crops and livestock are developed as a survival strategy and they are part of the paramo cultural heritage: practices learned from the Green Revolution and the traditional knowledge. These agricultural practices have generated conflicts between ecosystem conservation and improving the quality of life of its inhabitants. From the research it is proposed to implement community management plans, agroecological models, biocultural memory rescue and transformation in the agrarian structure.

Les pratiques agricoles et les conditions de vie de la communauté de la vereda El Bosque dans le Parc National Los Nevados, en Colombie, ont été analysées. Des différents outils ont été appliqués comme l'observation participative, les entretiens semi-structurés, les lignes de temps, les cartes de chaque vereda et ferme, les calendriers agricoles, les horloges des activités par genre et les questionnaires structurées. Il a été déterminé que la culture de pommes de terre et l'élevage de bétail se développent comme une stratégie de survivance et d'héritage culturel paramuna, des pratiques apprises depuis la révolution verte et les propres savoir-faire. Ces pratiques agricoles ont entraîné de contradictions entre la conservation de l'écosystème et l'amélioration de la qualité de vie de ses habitants. À partir de la recherche, il est proposé d'implémenter des projets de gestion communautaire, des modèles agro-écologiques, un sauvetage de la mémoire bio-culturelle et des transformations dans la structure agraire.

Amidase enzymatic activity was evaluated in soils under potato cropping with a conventional management with agrochemical application (PCA) and in soils under pasture without agrochemical application (PSA) in farms at Tausa, Villapinzón, and Zipaquirá located in the province of Cundinamarca (Colombia). Correlations between amidase enzymatic activity and other enzymatic activities related to the nitrogen cycle (e.g., urease and protease) and soil physicochemical parameters were also evaluated. The PCA samples showed null or low amidase activity compared to the PSA samples. The difference could be due to the application of agrochemicals and chemical supplements, which possibly affected soil microbiota and consequently the soil enzymatic activity. Similarly, the low amidase activity observed could be an indicator that carbofuran degradation via the amidase pathway did not occur at a significant level in the PCA soil. A direct relationship was observed between amidase, urease, and protease activities and the concentrations of soil microelements such as Mn, Fe, and Cu.

Se evaluó la actividad enzimática amidasa en suelos bajo cultivo de papa con manejo convencional de aplicación de agroinsumos (PCA) y en suelos bajo pastizal sin aplicación de agroinsumos (PSA), en fincas de las localidades de Tausa, Villapinzón y Zipaquirá en Cundinamarca (Colombia). Asimismo, se estableció su relación con la actividad de otras enzimas del ciclo del nitrógeno (ureasa, proteasa) y los parámetros fisico-químicos de dichos suelos. Se encontró que las muestras PCA presentaron nula o baja actividad amidasa con respecto a las PSA. Esto puede estar relacionado con la aplicación de plaguicidas e insumos químicos que afectan la actividad enzimática del suelo, o ser indicativo de que la degradación de carbofuran (plaguicida utilizado en el cultivo de papa) no se está llevando a cabo de manera significativa mediante la enzima amidasa. Se encontró una relación directa entre la actividad amidasa, ureasa, proteasa y micro-elementos del suelo (Mn, Fe y Cu).

En la vereda El Bosque del Parque Nacional Natural de Los Nevados (PNNN), Colombia, se estimó la densidad poblacional de microorganismos asociados con el metabolismo de nitrógeno (N) en suelos bajo tres sistemas de uso: cultivo de papa, ganadería y zonas poco intervenidas (páramo). Indirectamente se cuantificaron microorganismos amonificantes (AMO), proteolíticos (PRO), oxidantes del amonio (BOA), oxidantes del nitrito (BON) y denitrificantes (DEN) en suelos de tres fincas ubicadas a diferente altitud y en épocas seca y lluviosa. Se realizó la prueba no-paramétrica de Kruskal-Wallis por pares, con un nivel de significancia P < 0.05, para detectar diferencias estadísticamente significativas entre las diferentes abundancias de grupos funcionales de microorganismos. Luego, se realizó análisis de componentes principales (ACP) para evaluar las relaciones entre las diferentes variables estudiadas. Los resultados mostraron diferencias para los grupos evaluados, siendo menor la densidad de microorganismos en suelos de páramo. Los PRO fueron más abundantes en todos los tipos de suelos, seguido de los DEN con mayor densidad en el ecosistema páramo. La densidad poblacional microbiana no fue afectada por la altitud, sin embargo se presentaron algunas diferencias que no mostraron un patrón único de comportamiento. Se observaron diferencias como resultado de la época climática, siendo mayor en la época seca para los grupos PRO, AMO, BOA y BON, y en época de lluvias para los DEN. Este estudio contribuye al conocimiento de las relaciones que existen entre el uso del suelo y la presencia de los microorganismos asociados con el ciclo de nitrógeno.

This study estimated the population density of microorganisms associated with the metabolism of nitrogen (N) in soils with three uses: potato crop, livestock and low intervention zones (high plains or páramo) in the El Bosque district of Los Nevados National Natural Park in Colombia. The following microorganisms were indirectly quantified: amonifiers (AMO), proteolytic (PRO), ammonium oxidizing (BOA), nitrite oxidizing (BON) and denitrifiers (DEN) in soils of three farms located at different altitudes and under two climatic seasons. The non-parametric Kruskal-Wallis test paired with a significance level of P < 0.05 was used to detect statistically significant differences among abundances of functional groups of microorganisms. Then a principal component analysis (PCA) was performed to evaluate the relationships among different variables. The results showed differences among all the groups, with páramo soils having the lowest density of microorganisms in the soil. The PRO microorganisms were the most abundant in all soils, followed by DEN, with a higher density in the páramo ecosystem. The microbial population density was not significantly affected by altitude but showed some differences that did not have a unique behavior pattern. Additionally, differences were seen in the seasons, being higher in the dry season for the PRO, AMO, BOA and BON groups; and in the rainy season for DEN. This study provided knowledge of the relationships between land use and the presence of microorganisms associated with the nitrogen cycle.

Resumen. Se evaluaron las actividades enzimáticas (ureasa, proteasa, fosfatasa ácida y alcalina, fosfodiesterasa, b-glucosidasa y arilsulfatasa) en consorcios bacterianos (Bacillus subtilis, Brevundimonas diminuta, Flavimonas oryzihabitants) de suelos bajo cultivo de papa variedad Parda Pastusa, con manejo convencional de aplicación de agroinsumos (PCA) y en suelos bajo pastizal sin aplicación de agroinsumos (PSA), en fincas de tres localidades del departamento de Cundinamarca (Tausa, Villapinzón y Zipaquirá), Colombia. Se encontraron efectos por la aplicación de insumos de síntesis química y el tipo de uso del suelo, sobre las actividades enzimáticas; sin embargo, estos fueron diferentes para cada una de las enzimas y localidades. Para el municipio de Villapinzón la actividad de ureasa, fosfatasa ácida, fosfodiesterasa y b-glucosidasa, fue mayor en las muestras PCA con respecto a las PSA en un 89, 71, 67 y 75% respectivamente; para el municipio de Zipaquirá se presentó la misma tendencia en la actividad ureasa, b-glucosidasa y arilsulfatasa con un 50, 71 y 68% respectivamente; finalmente en el municipio de Tausa se mantuvo el mismo comportamiento para la actividad de proteasa, fosfatasa ácida, fosfatasa alcalina, fosfodiesterasa, b-glucosidasa, con un 55, 20, 75, 82 y 87% de mayor actividad en las muestras PCA en relación con las de PSA.

Abstract. Enzyme activities were evaluated (urease, protease, acid phosphatase and alkaline phosphodiesterase, b-glucosidase and arylsulfatase) in bacterial consortia (Bacillus subtilis, Brevundimonas diminuta, Flavimonas oryzihabitants) from either soil with potato cropping under conventional management with the application of agrochemicals (PWA) or grassland soils without the use of agrochemicals (GNA) on farms of three municipalities (Tausa, Villapinzón and Zipaquirá) in the department of Cundinamarca, Colombia. The type of land use and the location affected the tested enzymatic activities. In the municipality of Villapinzón urease, acid phosphatase, phosphodiesterase and b-glucosidase activity were higher in PWA than GNA by 89, 71, 67 and 75% respectively. The municipality of Zipaquirá presented the same trend in urease, b-glucosidase and arylsulfatase with higher activity in PWA than GNA by 50, 71 and 68% respectively. Finally in Tausa, the same behavior was found for protease, acid phosphatase, alkaline phosphatase, phosphodiesterase and b-glucosidase with 55, 20, 75, 82 and 87% higher activity in PWA than GNA.