A field experiment to determine the available bensulfuron-methyl (BSM) in the upper soil layer was conducted in an agricultural area in the South of Spain. To facilitate herbicide analysis, two application rates were employed, 200 g ha(-1) and 5 kg ha(-1). Samples of upper soil and soil solution were collected. Soil solution was sampled by means of metallic samplers, placed at a depth of 35 cm. In the plots receiving the lower dose ceramic suction, porous cups were also installed. Results from soil solution samples showed that the maximum BSM concentration was found after 8-10 days for the high irrigation supply (945 mm) and after 18-25 days for the lower irrigation regime (405 mm). The mathematical model FOCUSPELMO 1.1.1 was applied to interpret the data obtained in the field experiments. In general, there was a reasonable agreement between experimental and simulated data for soil samples, although the model did not acceptably predict herbicide concentrations in water soil samples. Ceramic cups sampled a higher soil water volume and more frequently than did the metallic samplers. However some variable results were attributed to preferential flow.
La miel es la sustancia dulce producida por las abejas obreras a partir del néctar de las flores o dela exudación de otras partes vivas de las flores presentes en ellas, que dichas abejas recogen, transforman y combinan con sustancias específicas, y almacenan después en panales. La miel es un producto natural ideal para la alimentación, porque en su composición química existen azúcares simples como la glucosa (40%) y fructosa (35%), que no necesitan transformación por los jugos gástricos para ser digeridos. Una vez ingerida, pueden ser asimilados y pasar a la sangre. donde proporcionan calor y energía (Bianchi, 1994). También se pueden encontrar otros tipos de azúcares como la sacarosa, maltosa y melicitosa.
The aim of this work was to study the influence of earthworms on the composting process. Selected waste mixtures pine sawdust + poultry litter (M1), cotton industry waste + poultry litter (M2), shredded paper + horse manure (M3), and cotton industry waste + horse manure (M4) were composted for 85, 64, 60 and 60 days respectively in plastic boxes. The temperature variations during this process followed the typical three-phase pattern. At the end of this process 95, 80, 75 and 95 g of Eisenia andrei were added to each treatment respectively to initiate vermicomposting. Together, the composting and vermicomposting processes took between 105 and 175 days. Earthworm biomass decreased in M1 and M2, and increased in M3 and M4. The physical, chemical and biological variables measured, such as time to compost maturity, the changes in earthworm population, the C/N ratio, and the availability of nutrients, showed that M3 was the best medium for earthworm activity, and that M4 had the best chemical and physical properties as an organic manure. Mixtures containing poultry litter were not suitable for vermicomposting. However, M1 was the best mixture in a test involving the growth of ryegrass (Lolium perenne cv. Weterwald); compared to controls, a 120% dry weight yield was obtained.
El término pesticida ó plaguicida agrupa una gran variedad de compuestos con estructuras y propiedades muy diferentes. Son productos químicos cuyo uso ha aumentado en grandes cantidades en las últimas décadas con el objeto de controlar las plagas, malezas y enfermedades que afectan a los cultivos. El comportamiento de los pesticidas en la biosfera está relacionado a su origen y fuente, su uso indiscriminado se ha convertido en un riesgo potencial como fuente de contaminación de las superficies del suelo y napas subterráneas, e incluso se han encontrado vestigios de pesticidas en muestras de aire.
A fin de determinar la residualidad de carbofuran en un Molisol al cabo de un tiempo de aplicación, se realizó un estudio en macetas de 1 kg de suelo a las que se agregó 100 mg L-1 de carbofuran. El suelo utilizado provino de una selección de dos lotes adyacentes, con y sin laboreo. Se tomaron muestras a dos profundidades, según tratamientos: L1 = Lote con cultivo (0 - 20 cm), L2 = Lote con cultivo (20 - 40 cm), L3 = Lote sin laboreo (0 - 20 cm) y L4 = Lote sin laboreo (20 - 40 cm). El muestreo de suelo se hizo a los 0, 7, 30 y 60 días de aplicación del pesticida. Según la residualidad de carbofuran y el nivel de materia orgánica se encontraron diferencias significativas entre fechas, uso y profundidad. La correlación entre contenido de carbofuran y materia orgánica, resultó significativa para L1 y L2 (0.52) teniendo cuenta el uso y según profundidad para L1 y L3 (-0.60). Observandose persistencia en todos los tratamientos en las fechas en que se extrajeron las muestras, siendo mayor en los que poseían un mayor tenor de materia orgánica.
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