Espectroscopía visible y del infrarrojo cercano para el análisis de nutrientes en tejido vegetal de caña de azúcar para producción de panela

La espectroscopía de reflectancia en el infrarrojo cercano (NIRS) es una tecnología rápida, multiparamétrica, amigable con el ambiente, de bajo costo y gran exactitud, para el análisis de diversos componentes en alimentos, en suelo y en agricultura. El objetivo del presente estudio fue construir modelos de calibración NIRS, para la predicción de nutrientes en tejido vegetal de caña de azúcar, para producción de panela, cultivada en la región de la Hoya del río Suárez. Un total de 416 muestras de tejido fueron escaneadas en el segmento espectral Vis-NIR. El análisis quimiométrico, se realizó con el software WinISI V4.10, aplicando la regresión de mínimos cuadrados parciales modificados, junto a una validación cruzada. Se evaluaron cuatro modelos con diferentes tratamientos matemáticos y el rendimiento de las calibraciones, se hizo por medio de la validación externa, analizando las medidas de bondad de ajuste, como el coeficiente de determinación de la predicción, el error estándar de la predicción ajustado por el sesgo y la desviación predictiva residual. Los resultados muestran que el modelo de calibración para N presentó el mayor poder predictivo. Para macronutrientes, las calibraciones, con mayor poder predictivo, fueron P y K y para micronutrientes, el modelo para B, mientras que para Cu presentó el más bajo poder predictivo. Se encontraron modelos adecuados para la predicción de los contenidos de N, Ca y P; para los demás nutrientes, se recomienda ampliar el conjunto de calibración.

Near Infrared Reflectance Spectroscopy (NIRS) is a fast, multiparametric, environmentally friendly, low-cost, and highly accurate technology for the analysis of components in food, soil, and agriculture. The purpose of this study was to generate NIRS calibration models for the prediction of nutrients in plant tissue of sugarcane to panela production cultivated in the Hoya del Río Suárez region. A total of 416 tissue samples were scanned in Vis-NIR spectral segment. Chemometric analysis was performed with the WinISI V4.10 software applying modified partial least squares regression with cross-validation. Four models with different mathematical treatments were evaluated, and the performance of calibrations was made through external validation analyzing the goodness-of-fit measures as prediction determination coefficient, standard error of the bias-adjusted prediction, and residual predictive deviation. The results showed that the calibration model for N had the highest predictive power. For macronutrients, the calibrations with the best predictive power were for P and K, and micronutrients for B, while Cu presented the lowest predictive power. Adequate models were found for the prediction of N, Ca, and P. In the case of the other nutrients, it is recommended to expand the calibration set.

Spatial analysis methodology of resistance to penetration and infiltration in a soil cultivated with a bushy fruit (Acca sellowiana)

The sustainable management of water and soil resources for agricultural purposes is related to the ability to store and mobilize available water for crops, particularly under a spatial analysis. The objective of the study was to design and evaluate a methodology for spatial analysis of resistance to soil penetration and infiltration on loamy-clay textures. The basic methodological principles included sampling grid planning, data capture at defined points, data fitting to empirical models, data processing, and spatial representation. A defining moment was evaluated for an established feijoa crop with permanent production. With a georeferenced rectangular sampling grid of 40m x 40m, an area of 1.36 ha was covered. Penetration resistance was measured with a penetrometer, covering 4 depths per node (sampled point). Infiltration was evaluated with ring infiltrometers. The results allowed validation of the methodology implemented through a single processing environment through RStudio. Resistance to penetration sensitively affected the variation in infiltration rates, adjusting planning activities for irrigation activities. The methodological proposal was designed to reduce processing times and graphic responses, tabulated, and integrated with a single script in the R tool, compared to traditional geostatistical techniques, which articulate the implementation of multiple tools for the generation of results.

La gestión sostenible de los recursos agua y suelo, con fines agrícolas, tiene relación con la capacidad para almacenar y movilizar agua disponible para los cultivos, particularmente, bajo un análisis espacial. El objetivo del estudio fue diseñar y evaluar una metodología de análisis espacial de la resistencia a la penetración e infiltración del suelo sobre texturas franco-arcillosas. Los principios básicos metodológicos incluyeron planificación de grilla de muestreo, captura de datos en puntos definidos, ajuste de datos a modelos empíricos, procesamiento y representación espacial de datos. Se evaluó un momento definido para un cultivo de feijoa establecido con producción permanente. Con una grilla de muestreo rectangular georreferenciada de 40m x 40m, se abarcó una superficie de 1,36 ha. La resistencia a penetración, se midió con un penetrómetro, cubriendo 4 profundidades por nodo (punto muestreado). La infiltración fue evaluada con anillos infiltrómetros. Los resultados permitieron validar la metodología implementada, mediante un entorno de procesamiento único, a través de RStudio. La resistencia a la penetración afectó sensiblemente la variación en las tasas de infiltración, ajustando actividades de planeación de actividades de riego. La propuesta metodológica fue diseñada para disminuir tiempos de procesamiento y respuestas gráficas, tabuladas e integradas en un único script en la herramienta R, comparado con técnicas tradicionales geoestadísticas, que articulan la implementación de múltiples herramientas para la generación de resultados.

Efecto del pH sobre la concentración de nutrientes en cacao (Theobroma cacao L.) en la Amazonia Colombiana / Effect of pH on the nutrient concentration in cocoa (Theobroma cacao L.) in the Colombian Amazon

RESUMEN La acidez del suelo limita la disponibilidad, la absorción y la concentración de nutrientes y el rendimiento del cultivo de cacao. El objetivo fue evaluar el efecto del pH del suelo sobre la concentración de nutrientes en hoja, cáscara y grano, para cuatro clones de cacao autocompatibles (ICS-1, CCN-51) y autoincompatibles (ICS-39, TSH-565), en el departamento del Caquetá. El diseño experimental consistió en un arreglo factorial con cuatro clones (factor A), cuatro niveles de pH y fertilidad (factor B) y cuatro repeticiones. Los resultados indican diferencias en la concentración de nutrientes por efecto del clon y tratamiento, siendo la acumulación de N, P y Mg en grano>hoja>cáscara, K en cáscara>hoja>grano, Ca, Fe, Mn, Zn y B en hoja>cáscara>grano, S en cáscara>hoja>grano y Cu en grano>cáscara>hoja. La concentración de P, Mg y S fue mayor y, a su vez, menor Mn, cuando aumentó el pH. El orden de extracción nutrimental en grano fue N>K>P>Mg>S>Ca>Fe>Mn>Zn>Cu>B. Con relación a los clones, CCN-51 presentó habilidad para la toma de nutrientes y alcanzar mayores producciones, incluso, en suelos con pH ≥ 5,5, lo que sugiere efecto de las condiciones edafoclimáticas y, por lo tanto, la necesidad de evaluar los clones para cada zona de cultivo.

ABSTRACT The soil acidity limits availability, absorption and concentration of nutrients and yield of the cocoa crop. The objective was to evaluate the effect of soil pH on the concentration of macro and micronutrients in leaf, husk and grain for four cocoa clones, self-compatible (ICS-1, CCN-51) and self-incompatible (ICS-39, TSH-565) in the department of Caquetá. The experimental design consisted in a factorial arrangement with four clones (factor A), four pH and fertility levels (factor B) and four repetitions. The results indicate differences in the concentration of nutrients due to the effect of the clone and the treatment, being the accumulation of N, P and Mg in grain>leaf>husk, K in husk>leaf>grain, Ca, Fe, Mn, Zn y B in leaf>husk>grain, S in husk>leaf>grain and Cu in grain>husk>leaf. The concentration of P, Mg and S was higher, and in turn Mn lower, when the pH increased. The order of nutrient extraction in grain was N>K>P>Mg>S>Ca>Fe>Mn>Zn>Cu>B. Regarding clones, CCN-51 showed ability to take nutrients and reach higher productions, even in soils with pH ≥ 5.5, suggesting effect of edaphoclimatic conditions, and therefore, the need to evaluate the clones for each growing area.

Una evaluación de las propiedades fisicoquímicas de suelo en sistema productivo de maíz - algodón y arroz en el Valle del Sinú en Colombia / An evaluation of soil physicochemical properties in corn - cotton, and rice production systems at the Sinu Valley in Colombia

RESUMEN Los sistemas de producción agrícolas en la subregión Valle del Sinú, en Colombia, en los últimos 50 años, se han basado en la siembra de cultivos en rotación o alternancia de maíz - algodón y arroz, y se caracterizan por el uso intensivo de implementos de mecanización e insumos agrícolas. El objetivo de este estudio fue evaluar las características fisicoquímicas de los suelos, bajo los sistemas productivos de maíz - algodón y arroz e identificar las principales limitantes de suelo, que afectan el desarrollo y la productividad de los cultivos, en la subregión Valle del Sinú. Para lo anterior, se realizaron muestreos de suelo en 64 sitios, distribuidos en cinco municipios del Valle del Sinú, evaluando propiedades físicas y químicas del suelo. El suelo en estudio pertenece al orden Inceptisol, moderadamente profundo, compuesto por arcillas expansivas y horizonte argílico. El suelo, se caracterizó por una reacción acida (5,82±0,87 a 6,78±0,34), contenido medio de MO. La media de la CIC varió en rango, de 18,45±2,94 a 22,85±4,36cmol(+) kg-1, la CE estuvo no salinos, variando de 0,29±0,09 a 0,91±1,70dS cm-1. Los contenidos de P, S, Ca, Mg y K fueron altos. La densidad aparente mostró valores promedios restrictivos para el desarrollo de raíces en cuatro de los cinco municipios, variando de 1,42±0,10 a 1,49±0,08g cm-3, excepto en San Carlos (1,33±0,14g cm-3). Los resultados obtenidos evidencian indicios de procesos de degradación de suelo, relacionados con el manejo de los suelos.

ABSTRACT The agricultural production systems in the Valle del Sinú subregion in Colombia, in the last 50 years, have been based on the sowing of crops in rotation and / or alternation of corn - cotton and rice, and are characterized by the intensive use of implements mechanization and agricultural inputs. The aim of this study was to evaluate the physicochemical characteristics of the soils under the corn - cotton and rice production systems and identifying the main soil limitations, which affect crop development and productivity, in the Sinú Valley Subregion. For the above, soil sampling was carried out at 64 sites distributed in five municipalities of the Sinú Valley, evaluating the physical and chemical properties of the soil. The soil under study belongs to the order Inceptisol, moderately deep, composed of expansive clays and argillic horizons. The soil was characterized by an acid reaction (5.82 ± 0.87 to 6.78 ± 0.34), average MO content. The mean of the CIC varied in the range of 18.45 ± 2.94 to 22.85 ± 4.36cmol(+) kg-1, the EC was not saline, varying from 0.29 ± 0.09 to 0.91 ± 1.70dS cm-1. The contents of P, S, Ca, Mg and K were high. The apparent density showed restrictive average values for root development in four of the five municipalities, ranging from 1.42 ± 0.10 to 1.49 ± 0.08g cm-3, except in San Carlos (1.33 ± 0.14g cm-3). The results obtained show evidence of soil degradation processes related to soil management.

Comparative Analysis of the Top Soil Properties under Forested and Deforested Zones: Implications for the Environment

An investigation was carried out to examine the properties of top soils between 0 and 15cm under both deforested and forested zones in Bowen University, Iwo, Nigeria. Top soil samples in the deforested zone was taken from the Main Gate area of the institution while that of the forested zone was taken from the forested area opposite staff quarters of the University. The soil samples were subjected to standard laboratory tests in the University central laboratory. The results showed that deforested soil has sandy, clay and silt contents of 72.4%, 9.2% and 18.4% respectively while forested soil has 65.2%, 10.8% and 24% in the same order. Also it was discovered that soil under deforestation has organic carbon, organic matter, pH, field capacity, moisture and electrical conductivity of 0.32%, 0.55%, 6.8, 0.72 g, 126.9 g and 230 µʃ/cm respectively while soil under forest has 0.45%, 0.77%, 7.1, 0.90 g, 0.72 g, 129.2 g and 275 µʃ/cm in the same order. The implications of this results is that removal of vegetation contributes to the release of carbon into the atmosphere which increases atmospheric heat, alkalinity of soil, loss of soil nutrients and also could pose limits to the survival of plant growth and also susceptibility of soil to surface wash. Thus, it is recommended that effort should be made to checkmate the removal of vegetation and if unavoidable, relevant policies should be put in place for edge development and its maintenance and also, reforestation steps as remedies to ensure sustainable environment.

Spatial dependency and correlation of properties of soil cultivated with oil palm, Elaeis guineensis, in agroforestry systems in the eastern Brazilian Amazon / Dependência espacial e correlação das propriedades do solo cultivado com dendezeiro, Elaeis guineensis, em sistemas agroflorestais na Amazônia Oriental

Geostatistics is a tool that can be used to produce maps with the distribution of nutrients essential for the development of plants. Therefore, the present study aimed to analyze the spatial variation in chemical attributes of soils under oil palm cultivation in agroforestry systems in the eastern Brazilian Amazon, and their spatial dependence pattern. Sixty spatially standardized and georeferenced soil samples were collected at each of three sampling sites (DU1, DU2, and DU3) at 0-20 cm depth. Evaluated soil chemical attributes were pH, Al3+, H+Al, K+, Ca2+, Mg2+, cation exchange capacity (CEC), P, and organic matter (OM). The spatial dependence of these variables was evaluated with a semivariogram analysis, adjusting three theoretical models (spherical, exponential, and Gaussian). Following analysis for spatial dependence structure, ordinary kriging was used to estimate the value of each attribute at non-sampled sites. Spatial correlation among the attributes was tested using cokriging of data spatial distribution. All variables showed spatial dependence, with the exception of pH, in one sampling site (DU3). Highest K+, Ca2+, Mg2+, and OM levels were found in the lower region of two sampling sites (DU1 and DU2). Highest levels of Al3+ and H+Al levels were observed in the lower region of sampling site DU3. Some variables were correlated, therefore cokriging proved to be efficient in estimating primary variables as a function of secondary variables. The evaluated attributes showed spatial dependence and correlation, indicating that geostatistics may contribute to the effective management of agroforestry systems with oil palm in the Amazon region.

A geoestatística é uma ferramenta utilizada para produzir mapas de distribuição de nutrientes essenciais para o desenvolvimento das plantas. O presente estudo teve como objetivo analisar a variação espacial dos atributos químicos do solo sob cultivo de dendê em sistemas agroflorestais na Amazônia Oriental brasileira, e seu padrão de dependência espacial. Sessenta amostras de solo espacialmente padronizadas e georreferenciadas foram coletadas em cada um de três locais de amostragem (UD1, UD2 e UD3), na profundidade de 0-20 cm. Os atributos químicos do solo avaliados foram: pH, Al3+, H+Al, K+, Ca2+, Mg2+, capacidade de troca catiônica do solo (CTC), P e matéria orgânica (MO). A dependência espacial dos atributos foi avaliada com análise semivariográfica, ajustando-se três modelos teóricos (esférico, exponencial e gaussiano). Após a análise de dependência espacial, a krigagem ordinária foi empregada para estimar os valores de cada atributo em locais não amostrados. A correlação espacial entre os atributos foi testada utilizando a cokrigagem para espacialização dos dados. Todas as variáveis mostraram dependência espacial, exceto pH em UD3. Os maiores teores de K+, Ca2+, Mg2+ e MO foram encontrados na região mais baixa da paisagem, em UD1 e UD2. Os maiores teores de Al3+ e H+Al foram observados na região mais baixa da paisagem, em UD3. Algumas variáveis foram correlacionadas, portanto a cokrigagem mostrou-se eficiente na estimativa das variáveis primárias em função das secundárias. Os atributos avaliados mostraram dependência e correlação espacial, indicando que a geoestatística pode contribuir para o manejo efetivo de sistemas agroflorestais com dendê na região amazônica.

Tropical soils characterization at low cost and time using portable X-ray fluorescence spectrometer (pXRF): Effects of different sample preparation methods / Caracterização de solos tropicais a baixo custo e tempo usando espectrômetro portátil de fluorescência de raios-X (pXRF): Efeitos de diferentes métodos de preparo de amostras

ABSTRACT Portable X-ray fluorescence spectrometer (pXRF) has been recently adopted by the Soil Science community for uses in both field and laboratory, obtaining the total content of several chemical elements in a few seconds. Sulfuric acid digestion is an expensive and time-consuming laboratory analysis that provides contents of Fe2O3, Al2O3, SiO2, TiO2 and P2O5, important for soil studies. Due to few pXRF studies in tropical soils, this work aimed to compare contents of Fe2O3, Al2O3, SiO2, TiO2 and P2O5 obtained by pXRF with sulfuric acid digestion results, and to evaluate the effects of varying forms of preparing soil samples and scanning with pXRF on the resulting values in Brazilian soils. Soils were scanned in five conditions in-field (in situ) and in laboratory, evaluating varying sample preparation methods, particle sizes and soil moisture. Four pXRF scanning operational modes were tested. Linear regressions were adjusted between results of pXRF and sulfuric acid digestion. Equations were validated with an independent set of samples. Statistical analyses compared the methods of preparing the samples. Adequate linear models reached R2 of 0.99 and 0.89 for Fe2O3 and TiO2, respectively. Validation promoted R2 greater than 0.97 and RMSE and ME close to zero for both oxides. Statistical differences of pXRF results were found among the methods of preparing samples. pXRF spectrometer has great potential to obtain Fe2O3 and TiO2 content rapidly and economically with high correspondence with laboratory results of sulfuric acid digestion analysis. Varying methods of preparing the samples promote differences in the results of pXRF.

RESUMO O espectrômetro portátil de fluorescência de raios-X (pXRF) foi recentemente adotado pela Ciência do Solo, para uso em campo e laboratório, para obtenção do conteúdo total de vários elementos químicos em poucos segundos. A digestão com ácido sulfúrico é uma análise laboratorial cara e demorada que fornece teores de Fe2O3, Al2O3, SiO2, TiO2 e P2O5, importantes para estudos sobre solos. Devido aos poucos estudos sobre o pXRF em solos tropicais, este trabalho objetivou comparar os teores de Fe2O3, Al2O3, SiO2, TiO2 e P2O5 obtidos pelo pXRF com os resultados de digestão com ácido sulfúrico e avaliar os efeitos de diferentes formas de preparo de amostras de solo e leitura com o pXRF sobre seus resultados para solos brasileiros. Os solos foram submetidos a leituras com o pXRF em cinco condições, em campo (in situ) e em laboratório, avaliando variados métodos de preparo de amostras, tamanhos de partículas e umidade do solo. Quatro modos de operação do pXRF foram testados. Regressões lineares foram ajustadas entre os resultados do pXRF e digestão com ácido sulfúrico. As equações foram validadas com um conjunto independente de amostras. Análises estatísticas compararam os métodos de leitura de amostras. Modelos lineares adequados atingiram R2 de 0,99 e 0,89 para Fe2O3 e TiO2, respectivamente. A validação promoveu R2 maior que 0.97 e RMSE e ME próximos a zero para ambos os óxidos. Foram encontradas diferenças estatísticas dos resultados do pXRF entre os métodos de preparo de amostras. O pXRF possui um grande potencial para obter rápida e economicamente os teores de Fe2O3 e TiO2 com elevada correspondência com os resultados laboratoriais da análise da digestão com ácido sulfúrico. Métodos variáveis ​​de preparo das amostras promovem diferenças nos resultados de pXRF.

The composition and diversity of arbuscular mycorrhizal fungi in karst soils and roots collected from mulberry of different ages / Composição e diversidade de fungos micorrízicos arbusculares em solos cársticos e raízes de amoreira de diferentes idades

ABSTRACT: Arbuscular mycorrhizal fungi (AMF) have been attracted more scientific attentions due to its critical role in enhancement of drought tolerance of plants for growth and vegetation restoration in karst fragile ecosystem. However, scientists know little about the AMF composition and diversity occurring in root systems of mulberry (Morus sp.), and in karst habitats which return land use from mulberry forestry, as well as the effects of soil environment change on the diversity of the AMF communities. To understand: (1) the AMF community composition and diversity at different stage of returning cropland to forest; and (2) the effects of soil environment change on the diversity of the AMF communities, soil and mulberry root samples were collected from Bijie and Libo sites, China, which experienced one and ten years, respectively, after returning croplands to forest. With the high throughput 454-sequencing technology, 8 known genera including 83 virtual species were distinguished and the genera Glomus, Paraglomus, Archaeospora and Diversispora were found to be dominant in soil and root sample. Compared to the samples in Libo, the genera Glomus, Paraglomus, Acaulospora and Claroideoglomus in root samples at Bijie site had a relatively abundance of species indicating that the returning cropland to forest is benefit to the AMF diversity and abundance, which was attribute to the variation of soil physiochemical properties. This conclusion is of great significance for guiding the return of farmland to forests.

RESUMO: Fungos micorrízicos arbusculares (FMA) tem atraído atenções de cientistas devido ao seu papel fundamental no crescimento e na restauração da vegetação de ecossistemas frágeis. No entanto, o conhecimento da composição e da diversidade da FMA em habitats cársticos e que retornem da agricultura para a silvicultura é limitado. Para entender: (1) a composição da Comunidade FMA e diversidade em fase diferente de retornar cultivo para a floresta; e (2) os efeitos da mudança do ambiente do solo sobre a diversidade das comunidades FMA, mostras de solo e de raiz de amoreira (Morus sp.) foram coletadas em Bijie e Libo, China, após um e dez anos de retorno ao cultivo dessa espécie, respectivamente, em sequência ao cultivo agrícola. Utilizando análise molecular e sequenciamento genético, constatou-se oito gêneros conhecidos e a distincão de oitenta e três espécies de FMA. Os gêneros Glomus, Paraglomus, Archaeospora e Diversispora foram dominantes, em solo e raízes. Em comparação as amostras de Libo, os gêneros Glomus, Paraglomus, Acaulospora e Claroideoglomus foram relativamente abundante nas raízes coletadas em Bijie, indicando que o retorno de uma área agrícola para o cultivo de amoreira é benéfico para a diversidade dos FMA, o que é atribuído as propriedades físico-químicas do solo. Essa conclusão é de grande importância para avaliar os efeitos do tipo de uso agrícola na microbiologia do solo.

Recuperación del funcionamiento hidrológico de ecosistemas de páramo en colombia / Rehabilitation of hydrological functioning of páramo ecosystems in colombia

Los páramos son ecosistemas que se caracterizan por una alta humedad relativa, alta frecuencia de niebla y por tener una vegetación arbustiva y herbácea, adaptada a las condiciones de alta montaña. En condiciones naturales estos ecosistemas presentan una oferta hídrica alta, entre otros servicios ecosistémicos; sin embargo, esto cambia cuando son degradados. A pesar de su importancia son ecosistemas que han sido modificados por el hombre, la mayoría aún sin haber sido estudiados. Este documento presenta los resultados de una investigación realizada en tres páramos en Colombia, en la cual, se evalúa su funcionamiento hidrológico y la capacidad de recuperación, una vez han sido alterados; para esto, se estudió el clima, la hidrología y los suelos. Los resultados indican que estos ecosistemas tienen condiciones climáticas desiguales, que determinan su rendimiento y regulación hídrica; con diferencias en las propiedades hidrofísicas del suelo y contenido de materia orgánica, lo que determina diferencias en su capacidad para retener la humedad y la disponibilidad de agua para las plantas. Estos resultados indican que los páramos, con un grado bajo de disturbio, presentan un alto rendimiento y buena regulación hídrica; pero igual que los páramos intervenidos, recuperan el estado natural de las propiedades del suelo y, consecuentemente, su funcionamiento hidrológico, aún en pocas décadas.

Páramos are equatorial alpine ecosystems characterized by a high air humidity, frequency of fog and the presence of shrub and herbaceous vegetation adapted to the specific equatorial alpine conditions. Under natural conditions these ecosystems present a high water yield, among other ecosystem services, however, this changes when they are degraded. Despite their importance, they are ecosystems that have been modified by man, most of them even without having been studied. This paper presents the results of a hydrological research carried out in three páramos in Colombia, which evaluates their hydrological functioning and their capacity for recovery once they are altered. Therefore, we studied their climate, hydrology, and soils properties. Results indicate that these ecosystems have different climatic conditions, which determine their water yield and water regulation. Differences in the hydro-physical properties of soils and organic matter content, which determine differences in their capacity to retain water and on the magnitude of the water available for plants. These results indicate that undisturbed páramos or with a low degree of disturbance present high water yield and good water regulation; and intervened páramos can recover the natural conditions of soil properties, and consequently their hydrological functioning, even in a few decades.

DESCRIPCIÓN DE SUELOS REPRESENTATIVOS DE ÁREAS NATURALES CON PRESENCIA DE POBLACIONES DE CHILE CHILTEPIN / DESCRIPTION OF REPRESENTATIVE SOILS OF NATURAL AREAS WITH PRESENCE OF CHILEAN POPULATIONS CHILTEPIN

En el presente estudio se realizó una selección de cuatro sitios con alta presencia de poblaciones de chile silvestre en un área de 85 km2, correspondiente al municipio de Mocorito, Sinaloa, México. Mediante la observación en campo, se decidió realizar un perfil de suelo en cada uno de los sitios, el cual consistió en la descripción de campo, análisis físico-químico e hidrofísico y la clasificación de los diferentes tipos de suelo. De esta forma se logró identificar un tipo de suelo por cada población de chile silvestre, estos corresponden al tipo de suelo Vertisol, Fluvisol, Leptosol y Feozem.

A selection of four sites was performed with high presence of populations of wild chilli in an area of 85 km2, corresponding to the municipality of Mocorito, Sinaloa, Mexico. Through field observations, it was decided to conduct a soil profile on each of the sites, which consisted in the description field and hidrofísico physicochemical analysis and classification of differents types of soil. Thus was identified a type of soil per population of wild chilli, these correspond to soil type Vertisol, Fluvisol, Leptosol and Feozem.

Evaluación de los hidrocarburos totales de petróleo (TPH) sobre suelos urbanos en Maicao, Colombia / Evaluation of total petroleum hydrocarbons (TPH) in urban soil from Maicao, Colombia / Avaliação de hidrocarbonetos totais de petróleo (TPH) em solo urbano em Maicao, Colômbia

Se evaluó la presencia de los hidrocarburos totales de petróleo (TPH) y sus efectos sobre propiedades de suelos en el área urbana de Maicao, Colombia. Se seleccionaron 18 sitios, nueve con derrames históricos y nueve sin ellos y se evaluaron dos profundidades (0-30 cm y 30-60 cm). Se extrajeron los TPH de las fracciones mediana (método reflujo en Soxhlet, EPA 3540C) y pesada (método de reflujo en Soxhlet, EPA 3550C). Se identificaron por cromatografía de gases con detector de ionización de flama (CG-FID). Se determinaron parámetros del suelo relacionados con su potencial de adsorción: pH, conductividad eléctrica (CE), carbono orgánico (CO), capacidad de intercambio catiónico (CIC), textura, retención de humedad del suelo y estabilidad de agregados. Se estableció alto contenido de todas las fracciones de TPH con efecto diferencial sobre las capas del suelo. No se encontraron cambios significativos para textura ni CE. Hubo incremento en el contenido de CO del suelo (500%), agregación y estabilidad de agregados (200%), ligera disminución del pH, CIC y retención de humedad del suelo (23,5% superficie). Estos resultados señalan la vulnerabilidad de los suelos dentro del casco urbano ante la contaminación por TPH y la exposición de la población humana a estos contaminantes.

The presence of total petroleum hydrocarbons (TPH) and their effects on soil properties in urban area of Maicao, Colombia, was evaluated. 18 sites were selected: nine contaminated and nine non-contaminated and two depths (0-30 cm and 30-60 cm) were evaluated. The medium TPH fraction (Soxhlet reflux method, EPA 3540C) and heavy TPH fraction (Soxhlet reflux method, EPA 3550C) were extracted. TPH were identified by gas chromatography with flame ionization detector (GC-FID). Soil parameters related potential adsorption were determined: pH, electrical conductivity (EC), organic carbon (OC), cation exchange capacity (CEC), texture; soil moisture retention, aggregate stability. High contents of TPH was found in all fractions. No significant changes were found for texture and (EC). There was an increase in the content of OC (500%), soil aggregation and aggregate stability (200%); slight decrease pH, CEC and soil moisture retention (23.5% soil surface). These results show the vulnerability of the urban soils to the TPH contamination and exposure of the human population to these contaminants.

Foi avaliada a presença de hidrocarbonetos totais de petróleo (TPH) e seus efeitos sobre as propriedades do solo na área urbana de Maicao, Colômbia. Foram selecionados 18 localidades, 9 com derrames históricos e 9 sem eles; 2 profundidades (0-30 cm e 30-60 cm). TPH foram extraídos do frações medianas (método do fluxo no Soxhlet, EPA 3540C) e frações pesadas (método refluxo Soxhlet, EPA 3550C). TPH foram identificados por cromatografia gasosa com detector de ionização de chama (CG/FID). Parâmetros do solo relacionados com potencial de adsorção foram determinados: pH, condutividade elétrica (CE), carbono orgânico (CO), capacidade de troca de cátions (CC), textura; retenção de umidade do solo; estabilidade de agregados. Foi estabelecido um elevado nível de TPH em todas as frações, com efeito diferencial nas camadas superficiais do solo. Não foram encontradas diferenças significativas para a textura e CE. Houve um aumento do CO do solo (500%), a agregação e a estabilidade dos agregados (200%); ligeira diminuição no pH, CC e retenção de umidade do solo (23,5% da superfície). Estes resultados mostram a vulnerabilidade dos solos dentro da cidade pela contaminação com TPH e exposição da população humana a estes contaminantes.

Effect of Sublethal Concentration of Heavy Metal Contamination on Soil Physicochemical Properties, Catalase and Dehydrogenase Activities.

The effect of sublethal contaminations (100 g/dm3) of heavy metals such as mercury (Hg), lead (Pb) and cadmium (Cd) on soil enzyme and physicochemical properties was investigated after one hundred and twenty days. Soil sample without heavy metal contamination served as the control. Results indicate that Hg, Pb and Cd at 100 g/dm3 concentration caused a significant (P<0.05) change in the soil pH and electrical conductivity relative to the control. There was no significant (P>0.05) difference in these soil physicochemical properties: moisture, phosphate, sulphate, chloride, calcium carbonate, total nitrogen and organic carbon when compared to the control. There were significant (P<0.05) decrease in soil dehydrogenase and catalase activities in all the metalcontaminated soil samples when compared to the control, indicating that these heavy metals increased soil acidity and electrical conductivity at this concentration and period of exposure.

Soil properties and root biomass responses to prescribed burning in young corsican pine (Pinus nigra Arn.) stands.

Fire is an important tool in the management of forest ecosystems. Although both prescribed and wildland fires are common in Turkey, few studies have addressed the influence of such disturbances on soil properties and root biomass dynamics. In this study, soil properties and root biomass responses to prescribed fire were investigated in 25-year-old corsican pine (Pinus nigra Arn.) stands in Kastamonu, Turkey. The stands were established by planting and were subjected to prescribed burning in July, 2003. Soil respiration rates were determined every two months using soda-lime method over a two- year period. Fine (0-2 mm diameter) and small root (2-5 mm diameter) biomass were sampled approximately bimonthly using sequential coring method. Mean daily soil respiration ranged from 0.65 to 2.19 g C m-2 d-1 among all sites. Soil respiration rates were significantly higher in burned sites than in controls. Soil respiration rates were correlated significantly with soil moisture and soil temperature. Fine root biomass was significantly lower in burned sites than in control sites. Mean fine root biomass values were 4940 kg ha-1 for burned and 5450 kg ha-1 for control sites. Soil pH was significantly higher in burned sites than in control sites in 15-35 cm soil depth. Soil organic matter content did not differ significantly between control and burned sites. Our results indicate that, depending on site conditions, fire could be used successfully as a tool in the management of forest stands in the study area.

Soil respiration and root biomass responses to burning in calabrian pine (Pinus brutia) stands in Edirne, Turkey.

In this study, soil properties and root biomass responses to prescribed fire were investigated in 25-30 year-old calabrian pine (Pinus brutia Ten.) stands in Edirne, Turkey. The stands were established by planting and were subjected to prescribed burning in July, 2005. Soil respiration rates were determined every two months using the soda-lime method over a two-year period. Fine (>2 mm diameter) and small root (>2-5 mm diameter) biomass were sampled approximately bimonthly using the sequential coring method. Soil respiration rates in burned sites were significantly higher than in control sites during the summer season but there was no significant difference in the other seasons. Soil respiration rates were correlated significantly with soil moisture and soil temperature. Fine and small root biomass were significantly lower in burned sites than in control sites. Mean fine root biomass values were 3204 kg ha-1 for burned and 3772 kg ha-1 for control sites. Annual soil CO2 releases totaled 515 g C m-2 for burned and 418 g C m-2 for control sites. Our results indicate that, depending on site conditions, fire could be used successfully as a tool in the management of calabrian pine stands in the study area.

The effects of land use change on soil properties and organic carbon at Dagdami river catchment in Turkey.

This research was carried out in Dagdami river catchment located in the highlands of the Black sea region of Turkey. The objective of this study was to investigate the effects of representative land-use and land-cover types of largely deforested areas of Black sea region on soil properties. We measured these effects by quantifying some soil analyses were done on soil samples were taken at two depths (0-5 and 5-15 cm) and two aspects (N and S). According to the results of statistical analysis, satured hydraulic conductivity (Ksat), bulk density (BD), water stable aggregates (WSA), soil organic matter (SOM), soil organic carbon (SOC) and total nitrogen significantly change with land use type and aspect. Results have shown significantly higher values of saturated hydraulic conductivity (Ksat) in natural forest top soil (82.4 cm3.h-1 on average) compared to grasslands soils (8.4 cm3 h-1) and hazelnut garden soils (11.5 cm3 h-1) and corn field soils (30.0 cm3.h-1). It was determined that WSA was greater in the pasture and forest soils than in cultivated soils. In addition, Ksat was found the highest value in the forest soils at all aspects while, SOM and SOC of forest soils are higher than other land use types. On the other hand, amount of SOM and SOC of soils of grassland, hazelnut garden and corn field are low level and close to each other. Soils under hazelnut garden (1.1 g cm-3) and grassland (1.1 g cm-3) have higher bulk density than the adjacent soils under forests (0.7 g cm-3) and corn field (1.0 g cm-3) for two different aspects. Furthermore, after long term continuous cultivation of the natural forest soil, it was determined that some physical and chemical characteristics of it has been significantly changed.