Germination and initial growth of tree seedlings on deforested and natural forest soil at Dulhazara, Bangladesh

The destruction of natural forest is increasing due to urbanization, industrialization, settlement and for the agricultural expansion over last few decades, and studies for their recovery need to be undertaken. With this aim, this comparative study was designed to see the effects of deforested soil on germination and growth performance of five different tree species. In the experiment, five species namely Gmelina arborea, Swieteniamahagoni, Dipterocarpus turbinatus, Acacia auriculiformis and Syzygium grande were germinated for six weeks on seedbeds and raised in pots (25cm diameter, 30cm height), that were filled with two soil and type of land use: deforested and adjacent natural forest of Dulhazara Safari Park. Growth performance of seedling was observed up to 15 months based on height, collar diameter and biomass production at the end. Our results showed that the germination rate was almost similar in both type of land uses. Height growth of D. turbinatus, G. arborea and S. mahagoni seedlings was almost similar and A. auriculiformis and S. grande lower in deforested soil compared to natural forest soil, while collar diameter of A. auriculiformis, G. arborea, S. grande and S. mahagoni lower and D. turbinatus similar in deforested soil compared to natural forest soil. After uprooting at 19 months, S. mahagoni seedlings were showed significantly (p≤0.05) higher oven dry biomass, D. turbinatus and A. auriculiformis higher, while G. arborea showed significantly (p≤0.05) lower and S. grande almost similar oven dry biomass in deforested soil compared to natural forest soil. Oven dry biomass of D. turbinatus seedlings at 19 month age in deforested soil was 21.96g (n=5) and in natural forest soil 18.86g (n=5). However, differences in germination rate and growth performance for different tree species indicated that soil are not too much deteriorated through deforestation at Dulhazara and without any failure such deforested lands would be possible to bring under forest through plantation.

La destrucción de los bosques naturales se está incrementando debido a la urbanización y la industrialización, así como por la expansión agrícola en las últimas décadas, por lo tanto deben llevarse a cabo los respectivos estudios para su recuperación. Este estudio comparativo fue diseñado para ver los efectos de la tierra deforestada en la germinación y crecimiento de cinco especies diferentes de árboles. Las especies Gmelina arborea, Swietenia mahagoni, Dipterocarpus turbinatus, Acacia auriculiformis y Syzygium grande fueron germinadas por seis semanas en semilleros y criadas en macetas que se llenaron con dos tipos de tierra: de los bosques deforestados y los adyacentes de Dulhazara Safari Park. El crecimiento de plántulas se observó por 15 meses basándose en altura, diámetro del cuello y producción de biomasa. La tasa de germinación fue casi similar en ambos tipos de tierra. El crecimiento en altura de plántulas de D. turbinatus, G. arborea y S. mahagoni fue casi similar y para A. auriculiformis y S. grande fue menor en el suelo deforestado en comparación con el bosque, mientras que el diámetro del cuello de A. auriculiformis, G. arborea, S. grande y S. mahagoni fue inferior y D. turbinatus similar en la tierra deforestada comparada con la del bosque. Después de arrancar de raíz a los 19 meses, S. mahagoni mostró mayor biomasa seca, así como D. turbinatus y A. auriculiformis, mientras que G. arbórea mostró ser más baja y S. grande casi similar en ambos tipos de suelo. Las diferencias en la tasa de germinación y de crecimiento para diferentes especies de árboles indica que el suelo no está muy deteriorado por la deforestación en Dulhazara y sin fallar esas tierras deforestadas podrían ser restauradas a través de la plantación.

Toxicological evaluation of vegetable oils and biodiesel in soil during the biodegradation process

Vegetable oils and their derivatives, like biodiesel, are used extensively throughout the world, thus posing an environmental risk when disposed. Toxicity testing using test organisms shows how these residues affect ecosystems. Toxicity tests using earthworms (Eisenia foetida. are widespread because they are a practical resource for analyzing terrestrial organisms. For phytotoxicological analysis, we used seeds of arugula (Eruca sativa and lettuce (Lactuca sativa. to analyze the germination of seeds in contaminated soil samples. The toxicological experiment was conducted with four different periods of biodegradation in soil: zero days, 60 days, 120 days and 180 days. The studied contaminants were soybean oil (new and used) and biodiesel (B100). An evaluation of the germination of both seeds showed an increased toxicity for all contaminants as the biodegradation occurred, biodiesel being the most toxic among the contaminants. On the other hand, for the tests using earthworms, the biodiesel was the only contaminant that proved to be toxic. Therefore, the higher toxicity of the sample containing these hydrocarbons over time can be attributed to the secondary compounds formed by microbial action. Thus, we conclude that the biodegradation in soil of the studied compounds requires longer periods for the sample toxicity to be decreased with the action of microorganisms.

Características bio-ecológicas en poblaciones de lombrices (Oligochaeta: Glossoscolecidae) de una sabana natural y una protegida en los llanos centrales de Venezuela / Bioecological characteristics of earthworm populations (Oligochaeta: Glossoscolecidae) in a natural and a protected savanna in the central Llanos of Venezuela

In tropical savannas, the earthworm communities have a predominant role since they regulate the soil structure and dynamics of the organic matter. To study the effect on earthworm populations in two differently managed savannas, we compared the general aspects of the biology and ecology of earthworm populations from a 40 years protected savanna (SP) with no fire or cattle raising at the Estación Biológica de los Llanos, Venezuela (EBLL), and a natural savanna (SNI), under normal burning and cattle raising management conditions. Sampling was carried out at the end of the dry season (April), and at the peak of the wet season (July-August). The main physical properties of soils per system were estimated. In each system, in plots of 90x90m, five fixed sampling units were selected at random; and at each sampling point one soil monolith of 25x25x30cm was collected per unit. Earthworms were extracted using the hand sorting extraction method; and the flotation method was used to estimate the density of cocoons. The earthworms were classified in different ecological categories considering their pigmentation, size and depth profile distribution. As a result of the savanna protection, physical parameters were modified in relation to SNI. The SP soils had higher soil moisture when compared to SNI. Soil moisture varied with depth during the dry season since, after the start of the rainy season, the soil was saturated. Field capacity in the SP was greater than that in the SNI. The surface apparent bulk density of soil was lower in the SP respect SNI, reflecting a lower soil compaction. Total average for the density and biomass of earthworms differed greatly, showing higher values in the SP. The earthworm density average in SP ranged between 25.6-85 individuals/m2 and the average biomass between 6.92-23.23g/m2. While in SNI, earthworms were only found in August, with a mean density of 22.40individuals/m2 and a mean biomass of 5.17g/m2. The vertical distribution pattern was only analyzed for the SP, and as in the SNI, no earthworms were found during the dry season; in the SP, a migration of earthworms to deeper layers during the dry season was observed; while in the rainy season they moved to upper soil layers to feed. The systems were characterized by abundance in juvenile Glossoscolecidae family earthworms which might be included in the endo-anecic ecological category. Results suggest that savanna agricultural management can modify an important fraction of pedofauna, particularly their earthworm communities, by modification of soil properties.

Las lombrices de tierra tienen un papel importante en el ciclado de nutrientes y el mantenimiento de la fertilidad de los suelos. En este estudio se empleo el método de extracción manual para determinar la densidad y la biomasa de las lombrices de tierra en diferentes profundidades y en diferentes estaciones, seleccionando al azar cinco monolitos de 25cm2x30cm, ubicados en un área de 90x90m en una Sabana Protegida (SP) y una Sabana Natural Intervenida (SNI). Adicionalmente, se estimó la densidad de los capullos, se analizaron las clases de etapas de desarrollo y se clasificaron los individuos en categorías ecológicas. Se estimó la humedad del suelo, la capacidad de campo, la temperatura, la densidad aparente y la textura del suelo. La SP presentó mejores condiciones físicas en el suelo que la SNI, mientras que la actividad de las lombrices de tierra estuvo limitada a los meses de lluvia y se observó un patrón de migración estacional en el perfil del suelo. En la SNI sólo se observó presencia de individuos en agosto y no se encontró diferencia significativa en sus biomasas con la SP. Los sistemas estuvieron dominados por individuos jóvenes con una categoría ecológica de tipo endo-anécica pertenecientes a la familia.

A review on soil carbon accumulation due to the management change of major Brazilian agricultural activities / Uma revisão sobre o acúmulo de carbono no solo devido a mudança de manejo nas principais atividades agrícolas do Brasil

Agricultural areas deal with enormous CO2 intake fluxes offering an opportunity for greenhouse effect mitigation. In this work we studied the potential of soil carbon sequestration due to the management conversion in major agricultural activities in Brazil. Data from several studies indicate that in soybean/maize, and related rotation systems, a significant soil carbon sequestration was observed over the year of conversion from conventional to no-till practices, with a mean rate of 0.41 Mg C ha-1 year-1. The same effect was observed in sugarcane fields, but with a much higher accumulation of carbon in soil stocks, when sugarcane fields are converted from burned to mechanised based harvest, where large amounts of sugarcane residues remain on the soil surface (1.8 Mg C ha-1 year-1). The higher sequestration potential of sugarcane crops, when compared to the others, has a direct relation to the primary production of this crop. Nevertheless, much of this mitigation potential of soil carbon accumulation in sugarcane fields is lost once areas are reformed, or intensive tillage is applied. Pasture lands have shown soil carbon depletion once natural areas are converted to livestock use, while integration of those areas with agriculture use has shown an improvement in soil carbon stocks. Those works have shown that the main crop systems of Brazil have a huge mitigation potential, especially in soil carbon form, being an opportunity for future mitigation strategies.

Áreas agrícolas trocam enormes fluxos de CO2, oferecendo uma oportunidade para mitigar o efeito estufa. Neste trabalho, estudou-se o potencial de sequestro de carbono em razão da conversão no manejo das principais atividades agrícolas do Brasil. Dados de vários estudos têm indicado que no sistema soja/milho e nas respectivas rotações, ocorre um sequestro de carbono no solo significativo ao longo dos anos de conversão do plantio convencional para o plantio direto, com uma média de 0,41 Mg C ha-1 ano-1. O mesmo efeito tem sido observado nos canaviais, porém há maiores acúmulos de carbono no solo quando as áreas de cana-de-açúcar são convertidas da colheita baseada na queima para a mecanizada, em que grandes quantidades de palha são deixadas na superfície do solo (1,8 Mg C ha-1 ano-1). Esse maior potencial de acúmulo de carbono no solo nos canaviais, comparado com outras culturas, está diretamente relacionado com a maior produção primária dessa cultura. Apesar disso, muito desse potencial de sequestro é perdido, uma vez que os canaviais são reformados, sob preparo intensivo do solo. As áreas de pasto mostram uma depleção nos estoques de carbono, quando convertidas de áreas naturais; porém, a integração dessas áreas com agricultura pode promover o aumento nos estoques de carbono do solo. Os trabalhos têm mostrado que as principais atividades agrícolas do Brasil possuem um grande potencial de mitigação, especialmente na forma de acúmulo de carbono no solo, sendo uma oportunidade para estratégias futuras.

Impact of transgenic cotton varieties on activity of enzymes in their rhizosphere.

The impact of five Bacillus thuringiensis (Bt) cotton varieties and their respective isogenic non-Bt(NBt) isolines (ANKUR-2534, MECH-6304, RCH-317, ANKUR-651 and MECH-6301) was assessed on the key soil enzymes i.e., dehydrogenase, alkaline phosphatase and urease in their rhizosphere at four growth stages of the crop, namely vegetative, flowering, bolling and harvesting. These varieties were grown on farmer’s field in villages 22 miles and 24 miles of Ganganagar District of Rajasthan State in India. Results showed that dehydrogenase, alkaline phosphatase and urease activities were higher in rhizosphere of Bt isolines as compared to NBt isolines of all the varieties. Except phosphatase, differences in dehydrogenase and urease activities in rhizosphere of Bt and NBt isolines of all five varieties were significant (P<0.05). Maximum enhancement in the three enzymes activities was observed in MECH-6304 Bt isoline rhizosphere. Maximum and minimum activities of dehydrogenase and urease were observed in MECH-6304 and RCH-317 Bt isolines, respectively, whereas phosphatase activity was maximum and minimum in MECH-6304 and ANKUR-651 Bt isolines, respectively. Maximum dehydrogenase and urease activities were observed at boll formation and minimum at flowering and harvesting stage, respectively, while maximum phosphatase activity was observed at vegetative stage and minimum at harvesting stage. In conclusion, all the studied Bt isolines of cotton varieties showed no adverse effect on dehydrogenase, alkaline phosphatase and urease activities in the rhizosphere.

Environmental lead poisoning among children in Porto Alegre state, Southern Brazil / Intoxicação ambiental por chumbo em crianças de Porto Alegre / Intoxicación ambiental por plomo en niños de Porto Alegre, Sur de Brasil

OBJECTIVE: To estimate the prevalence of lead poisoning in children and to identify associated factors, as well as possible local sources of contamination. METHODS: A cross-sectional prevalence study conducted in 2006 with a random sample of 97 children age zero to five years from a neighborhood in Porto Alegre, Southern Brazil. Blood lead levels were measured and a questionnaire administered to collect information on sociodemographics, recycling and dwelling. A preliminary environmental evaluation was carried out with direct analysis of soil and indirect analysis of air pollution with bioindicators to identify possible sources of contamination. To analyze lead concentrations from the different collection sites, for each type of material studied, ANOVA was performed with a Brown-Forsythe adjustment for heteroscedasticity and with Dunnett's T3 procedure for multiple comparisons of unequal variances. RESULTS: Blood lead levels > 10.0 µg/dL was found in 16.5 percent of children. Recycling of waste at home, low father's education level, and increased age of children were associated with increase blood lead levels. High lead levels were found in soil, and there was little indication of lead air pollution. CONCLUSIONS: A high prevalence of lead poisoning was identified, and the potential sources of contamination in this community appear related to waste recylcing activities. Studies should be conducted with other populations of Brazilian children and evaluate potential sources of local and general contamination, to accurately characterize this issue in Brazil.

OBJETIVO: Estimar a prevalência de intoxicação por chumbo em crianças e identificar fatores associados, bem como possíveis fontes de contaminação local. MÉTODOS: Estudo transversal de prevalência com amostra aleatória de 97 crianças de zero a cinco anos de uma vila em Porto Alegre, RS, em 2006. O nível de chumbo no sangue foi medido e foi aplicado questionário para coletar informações sociodemográficas, reciclagem e moradia. Foi realizada avaliação ambiental preliminar com análise direta do solo e indireta da poluição atmosférica utilizando bioindicadores para averiguar possíveis fontes de contaminação. Para avaliar diferenças significantes entre as concentrações encontradas nos pontos de coleta, para cada tipo de material estudado, foi realizada ANOVA com correção de Brown-Forsythe para heterocedasticidade com comparações múltiplas de Dunnett T3 para variâncias desiguais. RESULTADOS: O total de 16,5 por cento das crianças apresentou chumbo sanguíneo > 10,0µg/dL. Reciclagem de lixo no local de moradia, baixo nível educacional do pai e maior idade das crianças estiveram associados com maior concentração de chumbo no sangue. Foram encontrados níveis elevados de chumbo no solo e pouca indicação de poluição atmosférica por esse metal. CONCLUSÕES: Foi observada prevalência significativa de intoxicação por chumbo e as possíveis fontes de contaminação nessa comunidade parecem relacionar-se a atividades de reciclagem de lixo. Estudos devem ser conduzidos com outras populações infantis brasileiras, avaliando possíveis fontes de contaminação locais e gerais, para que se possa dimensionar corretamente essa questão no País.

OBJETIVO: Estimar la prevalencia de intoxicación por plomo en niños e identificar factores asociados, así como posibles fuentes de contaminación local. MÉTODOS: Estudio transversal de prevalencia con muestra aleatoria de 97 niños de cero a cinco años de una villa en Porto Alegre, Sur de Brasil, en 2006. El nivel de plomo en la sangre fue medido y se aplicó cuestionario para colectar informaciones sociodemográficas, reciclaje y vivienda. Se realizó evaluación ambiental preliminar con análisis directo del suelo e indirecto de la polución atmosférica utilizando bioindicadores para investigar posibles fuentes de contaminación. Para evaluar diferencias significativas entre las concentraciones encontradas en los puntos de colecta, para cada tipo de material estudiado, se realizó ANOVA con corrección de Brown-Forsythe para heterocedasticidad con comparaciones múltiples de Dunnett T3 para varianzas desiguales. RESULTADOS: Un total de 16,5 por ciento de los niños presentó plomo sanguíneo > 10,0µg/dL. Reciclaje de basura en el lugar de vivienda, bajo nivel educacional del padre y mayor edad de los niños estuvieron asociados con mayor concentración de plomo en la sangre. Se encontraron niveles elevados de plomo en el suelo y poca indicación de polución atmosférica por dicho metal. CONCLUSIONES: Se observó prevalencia significativa de intoxicación por plomo y las posibles fuentes de contaminación en la comunidad evaluada parecen relacionarse con actividades de reciclaje de basura. Estudios deben realizarse con otras poblaciones infantiles brasileñas, evaluando posibles fuentes de contaminación locales y generales, para que se pueda dimensionar correctamente este tema en el País.

Screening of actinomycetes from earthworm castings for their antimicrobial activity and industrial enzymes

Actinomycetes from earthworm castings were isolated and screened for their antimicrobial activity and industrial enzymes. A total of 48 isolates were obtained from 12 samples of earthworm castings. Highest numbers of isolates were recovered from forest site (58.33 %) as compared to grassland (25%) and agricultural land (16.66%). The growth patterns, mycelial coloration of abundance actinomycetes were documented. The dominant genera Identified by cultural, morphological and physiological characteristics were Streptomyces (60.41%) followed by Streptosporangium (10.41%), Saccharopolyspora (6.25%) and Nocardia (6.25%). Besides these, other genera like Micromonospora, Actinomadura, Microbispora, Planobispora and Nocardiopsis were also recovered but in low frequency. Among the 48 isolates, 52.08% were found active against one or more test organisms. Out of 25 active isolates 16% showed activity against bacterial, human fungal as well as phytopathogens. Among 48 isolates 38, 32, 21, 20, 16 and 14 produced enzyme amylase, caseinase, cellulase, gelatinase, xylanase and lipase respectively while 10 isolates produced all the enzymes. More interestingly 2, 3, and 1 isolates produced amylase, xylanase and lipase at 45°C respectively. In the view of its antimicrobial activity as well as enzyme production capability the genus Streptomyces was dominant. The isolate EWC 7(2) was most promising on the basis of its interesting antimicrobial activity and was identified as Streptomyces rochei. The results of these findings have increased the scope of finding industrially important actinomycetes from earthworm castings and these organisms could be promising sources for industrially important molecules or enzymes.

Changes in structure and composition of evergreen forests on an altitudinal gradient in the Venezuelan Guayana Shield

There have been several ecological studies in forests of the Guayana Shield, but so far none had examined the changes in structure and composition of evergreen forests with altitude. This study describes and analyzes the structure, species composition and soil characteristics of forest stands at different altitudinal zones in Southeastern Venezuelan Guayana, in order to explain the patterns and the main factors that determine the structure and composition of evergreen forests along the altitudinal gradient. Inventories of 3 948 big (>10cm DBH) and 1 328 small (5-10cm DBH) woody stems were carried out in eleven plots, ranging from 0.1 to 1.0ha, along a 188km long transect with elevations between 290 and 1 395masl. It has been found that 1) hemiepihytes become more dominant and lianas reduce their dominance with increasing altitude and 2) the forest structure in the study area is size-dependent. Five families and 12 genera represented only 9% of the total number of families and genera, respectively, recorded troughout the gradient, but the two groups of taxa comprised more than 50% of the Importance Value (the sum of the relative density and the relative dominance) of all measured stems. Moreover, the results suggest that low species richness seems to be associated with the dominance of one or few species. Stand-level wood density (WD) of trees decreased significantly with increasing elevation. WD is an indicator of trees’life history strategy. Its decline suggests a change in the functional composition of the forest with increasing altitude. The Canonical Correspondence Analysis (CCA) indicated a distinction of the studied forests on the basis of their altitudinal levels and geographic location, and revealed different ecological responses by the forests, to environmental variables along the altitudinal gradient. The variation in species composition, in terms of basal area among stands, was controlled primarily by elevation and secondarily ...

A pesar de los diversos estudios ecológicos realizados en los bosques del Escudo de Guayana, ninguno de ellos había analizado hasta ahora los cambios en la composición y estructura de bosques siempreverdes que ocurren al incrementar la altitud. Con el fin de identificar patrones y factores determinantes de la estructura y la composición de bosques en un gradiente altitudinal (290-1 395msnm) en el sudeste de Venezuela se realizaron inventarios de 3 948 fustes grandes (>10cm DAP) y 1 328 pequeños (5-10cm DAP) en once parcelas a lo largo de un transecto de 188km. Con el incremento de la altitud, el área basal aumenta en las hemiepífitas y disminuye en las lianas. Las familias y los géneros más importantes representaron una reducida proporción del total de taxones, pero abarcaron más del 50% del Valor de Importancia. Bajos valores de riqueza se asocian con la dominancia de pocas especies. La densidad de madera decrece significativamente a mayor altitud, y sugiere un cambio en la composición funcional. Existen diferentes respuestas ecológicas de los rodales ante cambios físico-ambientales. La variación de la composición de especies en el gradiente fue controlada por altitud, lluvia y condiciones edáficas; pero se desconoce el efecto de otros factores no considerados como régimen de perturbaciones, interacciones biológicas, productividad e historia de dispersión. La variabilidad observada en la estructura y la composición de bosques en el gradiente parece ser un resultado del efecto combinado de diferentes climas y procesos locales aleatorios que interactúan en un complejo paisaje.

Antifungal activities of some streptomyces strains-isolated from Rhisospheres of wild olea Europae and Juniper procera Trees

In the present study, 191 isolates of Streptomyces sp. were isolated from soil samples of the rhizospheres of Olea europae and Juniper procera trees from forests in Al-Baha region, Saudi Arabia. The isolates were grown on solid starch-casein medium and tested for their antifungal activities against some fungi. 88% of the isolates showed antifungal activity against seven fungi, Aspergillus ochraceus, A. nidulans, Circinella mucoroides, A. awamorli, A. terreus, Pencillium griseofulvum and A. niger. All isolates were able to completely inhibit the growth of A. achraceus and A. niger. Starch -casein was the best medium for producing the highest antifungal activity against most of tested fungi. The inhibition of growth of the tested fungi was increased by increasing the concentration of Streptomyces filtrate [grown on broth starch-casein medium]

Amylase production by solid-state fermentation of agro-industrial wastes using Bacillus sp

Solid state fermentation was carried out using various agro- industrial wastes with the best amylase producing strain isolated from soil. Different physicochemical conditions were varied for maximum enzyme production. The strain produced about 5400 units/g of amylase at 1:3 moisture content, 20 percent inoculum, after 72 h of incubation with Mustard Oil seed cake as the substrate. The optimum temperature and pH of the enzyme activity were found to be 50ºC and 6 respectively. The enzyme was found to be thermostable at 70ºC for about 2 h without any salt. It showed stability at pH range 5-7. The metal ions as Na+, Ca++, Mg++ and Co++ enhanced the enzyme activity.

Efeitos da suplementação com fósforo em caprinos no semiárido do nordeste brasileiro / Effect of phosphorus supplementation for goats in the Brazilian semiarid region

To evaluate the effect of phosphorus supplementation for goats grazing for the semiarid region, one group of 16 recently weaned Moxotó goats was supplemented with a mineral supplement containing Na, Cl, Zn, Cu, Se, Co, and P during 240 days. Another similar group was supplemented with a similar mineral supplement without P. The mean daily consumption of supplement by animal was of 7.09±2.77g and 7.67±3.14g for the groups with and without P, respectively. The mean weight gain of the P supplemented group (45.20±5.56g) was significantly higher (P<0.05) than the non-supplemented group (40.03±2.80g). The average total P in soil was 30.8mg/kg and in the pasture 0.13 percent in dry matter. These results demonstrate the occurrence of P deficiency in some areas of the Brazilian semiarid region.

Germination and soil seed bank traits of Podocarpus angustifolius (Podocarpaceae): an endemic tree species from Cuban rain forests

Podocarpus angustifolius is an endangered recalcitrant-seeded small tree, endemic to mountain rain forests in the central and Pinar del Río regions in Cuba. In this study, the germination patterns of P. angustifolius seeds were evaluated and the nature of the soil seed bank was determined. Using a weighted two-factor design, we analyzed the combined germination response to seed source (i.e. freshly matured seeds directly collected from trees versus seeds extracted from soil samples) and pretreatment (i.e. seed water-immersion for 48h at room temperature). Germination was delayed for four weeks (≈30 days) in all cases, regardless of both factors analyzed. Moreover, nine additional days were necessary to achieve high germination values (in the case of fresh, pretreated seeds). These results overall may indicate the existence of a non-deep simple morphophysiological dormancy in P. angustifolius seeds. The water-immersion significantly enhanced seed germination, probably as a result of the hydration of recalcitrant seeds. Although germination of seeds extracted from soil samples was low, probably due to aging and pathogen effects throughout the time of burial, the study revealed the existence of a persistent soil seed bank (at least short-termed) of ≈42 viable seeds per m² in the upper 10cm of soil. Such a record is noteworthy since references to persistent soil seed banks in recalcitrant-seeded species are scarce in the literature. The population consequences derived from the formation of persistent soil seed banks in this endangered species are discussed. Rev. Biol. Trop. 59 (3): 1061-1069. Epub 2011 September 01.

Podocarpus angustifolius es un árbol endémico de los bosques lluviosos de la región de Pinar del Río y la parte central de Cuba, que se encuentra en peligro de extinción. En este estudio se evaluó la germinación de sus semillas y la naturaleza del banco de semillas del suelo. Específicamente, se analizó la respuesta germinativa de las semillas a dos factores: su procedencia (recolectadas directamente de los árboles versus extraídas de muestras de suelo) y el pretratamiento (inmersión en agua durante 48h a temperatura ambiente). La germinación no comenzó hasta las cuatro semanas (≈30 días) en todos los casos. Además, fueron necesarios 9 días más para alcanzar un valor elevado de germinación (en el caso de semillas recolectadas del árbol con pretratamiento), lo que parece indicar la existencia de un letargo de tipo morfofisiológico simple no profundo. El pretratamiento incrementó significativamente la germinación, posiblemente por hidratación de las semillas recalcitrantes. El estudio demostró la existencia de un banco de semillas persistente en el suelo, al menos de corta duración de ≈42 semillas viables por m² en los 10 primeros cm del suelo. Dicho hallazgo es destacable, ya que los casos descritos en la literatura sobre bancos persistentes en especies con semillas recalcitrantes son escasos. Además, se discute la importancia que tiene para esta especie amenazada la existencia de un banco de semillas persistente.

Contaminação parasitária de solo em praças públicas da zona leste de São Paulo, SP - Brasil e a associação com variáveis metereológicas / Soil contamination with parasites in public squares in the east zone of Sao Paulo, Brazil and the association with meteorological variables

Vários estudos têm demonstrado a contaminação de ambientes públicos abertos à comunidade por parasitos com potencial zoonótico e propagadores de infecções humanas. De acordo coma Organização Mundial da Saúde, as helmintíases transmitidas pelo solo (Soil-transmitted helminthiases – STH) estão entre as 17 neglected tropical diseases e atingem mais de um bilhão de pessoas das regiões mais pobres do mundo. Neste estudo, verificou-se a contaminação por parasitos em praças públicas da zona leste da cidade de São Paulo, Brasil, no período de setembro de2008 a outubro de 2009, e avaliou-se a existência de relação entre esta contaminação e as variáveis precipitação e temperatura. As amostras, coletadas em dez localidades públicas, foram processadas pela técnica de flotação em solução saturada de cloreto de sódio. Das 300 amostras analisadas, 83,7por cento revelaram-se positivas, com média de 11 a 2 ovos por grama de peso seco nas praças públicas. Foram mais frequentes os parasitos dos gêneros Toxocara spp e Ascaris spp com 44,5por cento e 34,2por cento, respectivamente. Além deles foram observados ainda: Larvas de Nematoda (16,2por cento), Ancilostomídeos (3,8por cento), Enterobius sp (0,6por cento), Hymenolepis spp (0,4por cento), Capillaria sp (0,2por cento) e Trichuris sp (0,1por cento). Os meses com maior pico de encontro de ovos férteis, ovos inférteis, cistos e larvas destes parasitos foram os da estação chuvosa, ou seja, de outubro a março, sendo maiores os índices de ovos férteis. As variáveis precipitação e temperatura tiveram correlação com o númerototal de ovos viáveis e/ou inviáveis (p igual 0,02 e 0,09). Estes dados indicam a existência de risco de contaminação parasitária nas praças públicas estudadas, sendo maior nos períodos com índices mais altos de precipitação e elevada temperatura, de acordo com a Organização Mundial da Saúde.

Several studies have demonstrated the contamination of public places with parasites with zoonotic potential and propagators of human infections. The soil-transmitted helminths are among the seventeen “Neglected Tropical Diseases”, according to World Health Organization, and affect more than one billion people in the poorest regions of the world. We studied the contamination by parasites in public squares in the eastern region of the city of São Paulo, Brazil, between September 2008 and October 2009, and evaluated whether there is a relationship between this contamination and the variables of precipitation and temperature. The samples, collected from ten public localities, were processed by the flotation technique in saturated solution of sodium chloride. Of the 300 samples tested, 83.7% were positive. An average from 11 to 2 eggs per gram dry weight was found. The parasitesmore often found were of the genus Ascaris spp and Toxocara spp with proportions of 44.5% and 34.2%, respectively. In addition, Nematode Larvae (16.2%), Hookworm (3.8%), Enterobius sp (0.6%), Hymenolepis spp (0.4%), Capillaria sp (0.2%) and Trichuris sp (0.1%) were also observed. Higher prevalence of fertile eggs, infertile eggs, cysts, and larvae of the parasite occurred in the rainy seasonwhich lasts from October to March, of these the most prevalent were fertile eggs. The precipitation and temperature variables were correlated with the total number of viable and / or nonviable eggs (p= 0.02 and 0.09).

Variación en la actividad microbiana por cambio de uso en suelos en sabanas, Llanos Orientales, Venezuela

Soil microbial activity variation after land use changes in savannah, Llanos Orientales, Venezuela. In West plains of Venezuela, the traditional land use of the Trachypogon savannah, has been the extensive grazing. The pressure over these savannahs to obtain a major animal productivity has stimulated the introduction of exotic forage plants, such as Brachiaria brizantha and Andropogon gayanus. In spite that great savannah extensions have been subject to this land use change, information about the effect that pastures and grazing activity have on microbial activity in these soils is scarce. So the objective of this study was to determine the impact that the extensive grazing and cover substitution have on microbial activity. The soil sampling was carried out during the dry and rainy seasons. The employed parameters to determine changes in soil microbial activity were the substrate induced respiration (SIR), basal respiration (BR), the dehydrogenase activity (DHS), the fluorescein diacetate hydrolysis (FDA) and the arginene ammonification (AA). The similarity of the structural soil characteristics studied allows us to infer, that the differences in the microbiological parameters are determined by climatic conditions and soil management. The results show that there is a low microbial activity in these soils. The rainy season caused an increase in all the microbiological parameters determined. B. brizantha made a greater contribution to soil carbon and promoted a greater heterotrophic activity. The extensive grazing and the low stocking rate in the West plain savannas did not affect the microbial activity in these soils. Rev. Biol. Trop. 59 (1): 1-15. Epub 2011 March 01.

En los llanos orientales de Venezuela la forma tradicional de uso de las sabanas de Trachypogon ha sido el pastoreo extensivo. La presión sobre éstas para obtener una mayor productividad animal ha estimulado la introducción de plantas exóticas para forrajes, tales como: Brachiaria brizantha y Andropogon gayanus. A pesar de que grandes extensiones de sabanas están siendo sometidas a este cambio de uso de la tierra, es escasa la información acerca del efecto que estas pasturas y la actividad de pastoreo tienen sobre la actividad microbiana en el suelo; por lo que el objetivo del presente estudio fue determinar el impacto que el pastoreo extensivo y la substitución de la cobertura nativa tienen sobre la actividad microbiana en estos suelos. El muestreo fue llevado a cabo durante las temporadas de sequía y lluvias. Los parámetros empleados para determinar cambios en la actividad microbiana fueron la respiración inducida por sustrato (RIS), la respiración basal (RB), la actividad de la deshidrogenasa (DHS), la hidrólisis del diacetato de fluorisceína (DAF) y la amonificación de la arginina (AA). La similitud de las características estructurales de los suelos estudiados nos permite inferir, que las diferencias en los parámetros microbiológicos, están determinadas por las condiciones climáticas y el manejo del suelo. Los resultados muestran que en estos suelos existe una baja actividad microbiana. La temporada lluviosa provocó un incremento en todos los parámetros microbiológicos determinados. B. brizantha hizo un mayor aporte de carbono al suelo y promovió una mayor actividad heterotrófica. El pastoreo extensivo y la baja carga animal en las sabanas de los llanos orientales de Venezuela no afectaron la actividad microbiana del suelo.

Descomposición de hojarasca y liberación de nutrientes en plantaciones de Acacia mangium (Mimosaceae) establecidas en suelos degradados de Colombia

Litter decomposition and nutrient release in Acacia mangium plantations established on degraded soils of Colombia. Several factors control the decomposition in terrestrial ecosystems such as humidity, temperature, quality of litter and microbial activity. We investigated the effects of rainfall and soil plowing prior to the establishment of Acacia mangium plantations, using the litterbag technique, during a six month period, in forests plantations in Bajo Cauca region, Colombia. The annual decomposition constants (k) of simple exponential model, oscillated between 1.24 and 1.80, meanwhile k1 y k2 decomposition constants of double exponential model were 0.88-1.81 and 0.58-7.01. At the end of the study, the mean residual dry matter (RDM) was 47% of the initial value for the three sites. We found a slow N, Ca and Mg release pattern from the A. mangium leaf litter, meanwhile, phosphorus (P) showed a dominant immobilization phase, suggesting its low availability in soils. Chemical leaf litter quality parameters (e.g. N and P concentrations, C/N, N/P ratios and phenols content) showed an important influence on decomposition rates. The results of this study indicated that rainfall plays an important role on the decomposition process, but not soil plowing. Rev. Biol. Trop. 59 (1): 113-128. Epub 2011 March 01.

La descomposición de hojarasca en los ecosistemas terrestres está regulada por varios factores, entre ellos, la humedad, temperatura, calidad de la hojarasca y la actividad de los microoganismos. Estudiamos el efecto de la precipitación y el tratamiento de subsolado del suelo previo establecimiento de plantaciones de Acacia mangium, usando la técnica de bolsas de descomposición durante seis meses en plantaciones del Bajo Cauca (Colombia). La constante de descomposición anual (k) del modelo simple exponencial, osciló entre 1.24 y 1.80. Las constantes k1 y k2 del modelo doble exponencial fluctuaron entre 0.88-1.81 y 0.58-7.01. Al final del experimento la materia seca residual promedio (MSR) fue del 47%. Las cantidades residuales de N, Ca y Mg en la hojarasca de A. mangium mostraron un patrón de liberación lento. La evolución del P en la MSR mostró un proceso dominante de inmovilización, dada su baja disponibilidad en el suelo. Algunos parámetros de calidad del sustrato (N, P, C/N, N/P y fenoles) fueron buenos predictores del proceso, así como la precipitación, situación contraria a la del tratamiento de subsolado.

Influência alelopática de hortelã (Mentha x villosa Huds. ) sobre emergência de plântulas de alface (Lactuca sativa L. ) / Allelopathic influence of mint (Mentha x villosa Huds. ) on the emergence of lettuce (Lactuca sativa L. ) seedlings

Objetivou-se com esse trabalho avaliar a interferência de possíveis efeitos alelopáticos de Mentha x villosa Huds. sobre a emergência de Lactuca sativa L. As atividades foram conduzidas em laboratório, no Instituto de Ciências Agrárias (ICA) da Universidade Federal de Minas Gerais, em Montes Claros/MG. Foram propostos três tratamentos, sendo esses: solo A, coletado em área cultivada com hortelã no horto medicinal do ICA/UFMG; solo B, coletado em áreas adjacentes e, testemunha (papel germiteste).O delineamento experimental foi inteiramente casualizado (DIC), com sete repetições. As variáveis avaliadas foram: porcentagem e índice de velocidade de emergência. Observou-se que a emergência de plântulas de Lactuca sativa foi significativamente afetada pelo solo A (6,95 por cento) se comparada com o solo B (21,71 por cento), representando assim, uma inibição da emergência, ou seja, efeito alelopático da hortelã sobre a emergência de alface. Já o índice de velocidade de emergência (IVE) não diferiu significativamente entre os solos testados.

This study aimed to assess the interference of possible allelopathic effects of Mentha x villosa Huds. on the germination of Lactuca sativa L. The activities were carried out in laboratory, at the Institute of Agricultural Sciences (ICA) of the Federal University of Minas Gerais, Montes Claros, Minas Gerais State, Brazil. The following three treatments were proposed: soil A, collected in area cultivated with mint at the garden of ICA; soil B, collected in adjacent areas; and control (germitest paper). Experimental design was completely randomized (CR), with seven replicates. The evaluated variables were: germination percentage and speed index. The emergence of Lactuca sativa seedlings was significantly affected by soil A (6.95 percent) when compared to soil B (21.71 percent), indicating thus emergence inhibition, i.e. an allelopathic effect of mint on lettuce emergence. On the other hand, the germination speed index (GSI) did not differ significantly between the tested soils.

Estimating radiation dose from building materials

Natural radioactivity in materials under certain conditions can reach the hazardous radiological levels. So, it becomes necessary to study the natural radioactivity in different materials to assess the dose for the population in order to know the health risks and to have a baseline for future changes in the environmental radioactivity due to human activities. The present study deals with the measurement of radioactivity using "gamma-ray spectrometry" from naturally occurring radionuclides in the soil, stone and sand samples used as building materials in North-Eastern Haryana state of India. The places are in the vicinity of Shivalik range of Himalayas. The activity concentrations for 226Ra, 232Th and 40K varied from 18 +/- 1.5 to 156 +/- 6Bqkg[-1], 23 +/- 1 to 300 +/- 5Bqkg[-1] and 32 +/- 0.5 to 1705 +/- 14 Bqkg[-1] respectively in various samples. The absorbed dose rate in soil, sand and stone samples is investigated at 1 m above ground level. Ra equivalents, Internal and external hazard indices have also been calculated. The natural radioactivity levels measured in the samples under present study are below the recommended limits except for black stone [SB] and red stone [SR]. However, these samples satisfy the universal standards

Assessment of feather hydrolysate from thermophilic actinomycetes for soil amendment and biological control application

Protein-rich hydrolysate from feather waste was obtained using a mixed culture of selected thermophilic actinomycete strains, and was tested for possible application as soil amendment and biological control agent. For this purpose, a 4 months laboratory experiment was carried out using two types of urban soils [Sofia, Bulgaria]: native park soil and anthropogenic soil. The effect of the obtained hydrolysate on some soil parameters [pH, some enzyme activities and microbial activity], seed germination and ryegrass growth, and activity against some plant pathogenic fungi was studied. The results demonstrated that soil enrichment with the organic solution in low concentrations exerted a positive effect on soil urease and microbial activity, seed germination and ryegrass growth, and this trend was better expressed in the anthropogenic soils. Feather hydrolysate showed good activity against plant pathogenic fungi Fusarium solani, Fusarium oxysporum, Mucor sp. and Aspergillus niger. Produced antifungal compounds were isolated and partially characterized as amphiphilic peptides. To the best of our knowledge, antifungaLpeptides produced by Thermoactinomyces sp. have not been reported. Therefore, the feather hydrolysate obtained by means of the mixed culture of Thermoactinomyces strains has potential to be used as alternative organic amendment for restoration of contaminated soils and for accelerating ryegrass growth. It could successfully used also for as biocontrol agent applicable to crop plant soil

Measuring gamma -ray dose of terrestrial samples using beta - gamma spectrometry

The existence of some radionuclides in soil and some building materials produce a beta - gamma radiation field, which in some regions the exposure of these radionuclides to human is high. The air-absorbed dose, indoor and outdoor annual effective dose of soil and some building material samples [ceramic, granite, gypsum, etc.]. The samples were collected from 35 different regions in the northwest of Iran were calculated. Specific activity of natural radionuclides [226]Ra, [232]Th and [40]K were measured by using a beta - gamma spectrometer consisted of NaI[Tl] and organic scintillators. The analysis of measured spectra was based on maximum likelihood estimation. The calculated data were compared with world's mean values. It is found that the specific activity of 40K ranges from 573.8 to 1392 Bqkg[-1], for [232]Th ranges from 6 to 54.6 Bqkg[-1] and for [226]Ra ranges from and 5.1 to 36.2 Bqkg-1. In some regions, the concentrations of natural radionuclides [[40]K, [232]Th, [226]Ra] were higher than standard level. Experimental results related to specific activity, indoor and outdoor annual effective doses of [226]Ra, [232]Th and [40]K revealed that radionuclide concentration in soil and some building material samples of some regions of northwest of Iran are of some radiological importance

The effect of climate and soil conditions on tree species turnover in a Tropical Montane Cloud Forest in Costa Rica

On a global level, Tropical Montane Cloud Forests constitute important centers of vascular plant diversity. Tree species turnover along environmental gradients plays an important role in larger scale diversity patterns in tropical mountains. This study aims to estimate the magnitude of beta diversity across the Tilarán mountain range in North-Western Costa Rica, and to elucidate the impact of climate and soil conditions on tree species turnover at a local scale. Seven climate stations measuring rainfall, horizontal precipitation (clouds and wind-driven rain) and temperatures were installed along a 2.5km transect ranging from 1 200m.a.s.l. on the Atlantic to 1 200m.a.s.l. on the Pacific slope. The ridge top climate station was located at 1 500m.a.s.l. Climate data were recorded from March through December 2003. Additionally, seven 0.05ha plots were established. On all plots soil moisture was monitored for one year, furthermore soil type and soil chemistry were assessed. Woody plants with a diameter at breast height (dbh) ≥5cm were identified to species. Species’ distributions were explored by feeding pairwise Sørensen measures between plots into a Principal Component Analysis. Relationships between floristic similarity and environmental variables were analyzed using Mantel tests. Pronounced gradients in horizontal precipitation, temperatures and soil conditions were found across the transect. In total, 483 woody plants were identified, belonging to 132 species. Environmental gradients were paralleled by tree species turnover; the plots could be divided in three distinctive floristic units which reflected different topographic positions on the transect (lower slopes, mid slopes and ridge). Most notably there was a complete species turnover between the ridge and the lower Pacific slope. Floristic similarity was negatively correlated with differences in elevation, horizontal precipitation, temperatures and soil conditions between plots. It is suggested that beta-diversity in the study area is largely driven by species with narrow spatial ranges, due to the interactions between topography, climate and soil formation processes, especially around the wind-exposed and cloud covered ridge area. The findings emphasize the extraordinary conservation value of tropical montane cloud forests in environmentally heterogeneous areas at mid-elevations. Rev. Biol. Trop. 58 (4): 1489-1506. Epub 2010 December 01.

A nivel global, los bosques nubosos tropicales constituyen importantes centros de diversidad florística. El recambio de especies a través de gradientes ambientales juega un papel importante en los patrones de diversidad en las montañas tropicales. Este estudio tiene como objetivo estimar la diversidad beta de plantas leñosas a través de la Cordillera de Tilarán en el noroeste de Costa Rica y aclarar el impacto del clima y las condiciones del suelo en la distribución de especies a una escala local. Se instalaron siete estaciones meteorológicas, en las cuáles se midió lluvia, precipitación horizontal y temperatura, a lo largo de un transecto de 2.5km desde 1 200msnm de altitud en la vertiente Atlántica a 1 200msnm en la vertiente Pacífica. La estación de la cima se localizó a 1 500msnm. Los datos climáticos se registraron entre marzo y diciembre del 2003. Además, se establecieron siete parcelas de 0.05ha. En cada parcela se monitoreó la humedad del suelo por un año. Se determinaron los tipos de suelo y sus propiedades químicas. Las plantas leñosas con un diámetro ≥5cm fueron identificadas. La distribución de las especies fue explorada insertando las medidas Sørensen entre parcelas en un Análisis de Componentes Principales. Las relaciones entre la similitud florística y las variables ambientales se analizaron mediante pruebas de Mantel. Se encontraron gradientes pronunciados en la precipitación horizontal, temperaturas y condiciones del suelo a través del transecto. En total, se identificaron 483 plantas leñosas, pertenecientes a 132 especies. El recambio de especies leñosas se efectuó de forma paralela a los gradientes ambientales; según los análisis las parcelas se dividen en tres unidades distintivas florísticas que reflejan diferentes posiciones topográficas del transecto. Notablemente se produjo un recambio total de especies entre la cima y la vertiente Pacifica inferior. La similitud florística fue correlacionada negativamente con las diferencias de altitud, precipitación horizontal, temperaturas y condiciones del suelo entre las parcelas. Se sugiere que la diversidad beta en el área de estudio resulta en gran parte de la distribución de especies con rangos limitados, debido a las interacciones entre la topografía, el clima y los procesos de formación del suelo, especialmente alrededor de la cima que está expuesta a los vientos alisios y frecuentemente cubierta de nubes. Los resultados subrayan el valor de conservación extraordinaria que tienen los Bosques Nubosos Tropicales en áreas ambientalmente heterogéneas en alturas medianas.