Necesidades de información meteorológica en el sector agrario

Presentación realizada en: Jornada sobre "Servicios meteorológicos y climáticos para el sector agrario", celebrada el 30 de mayo de 2013 en la sede central de AEMET en Madri

Comparison of structure function and detrended fluctuation analysis of wind time series

A multifractal (MF) analysis in time scale has been applied to three wind speed series presenting a different pattern. The temporal scaling properties of the records, registered each 10 minutes, were studied using two different methods, structure function (SF) and detrended fluctuation analysis (DFA), to establish a comparison of the results and their interpretation in the geostrophic turbulence context. A systematic analysis of the exponent of the structure function (ζ(q)) and the generalized Hurst exponents (H(q)) gave, in general terms, equivalent results when a comparison is applied among the three months. However MF DFA presented statistically more robust results. This allowed us to see a clear difference between the parameters studied for each month: linear component of ζ(q) (ζ(q = 1) = H), intermittency of the wind series (μ), deviation from linear structure function (λ), Hurst exponent (H(q = 2)) and H(q) dependence on q (ΔH)

Topology of a percolating soil pore network.

A connectivity function defined by the 3D-Euler number, is a topological indicator and can be related to hydraulic properties (Vogel and Roth, 2001). This study aims to develop connectivity Euler indexes as indicators of the ability of soils for fluid percolation. The starting point was a 3D grey image acquired by X-ray computed tomography of a soil at bulk density of 1.2 mg cm-3. This image was used in the simulation of 40000 particles following a directed random walk algorithms with 7 binarization thresholds. These data consisted of 7 files containing the simulated end points of the 40000 random walks, obtained in Ruiz-Ramos et al. (2010). MATLAB software was used for computing the frequency matrix of the number of particles arriving at every end point of the random walks and their 3D representation

Network models of soil porous structure

Soils sustain life on Earth. In times of increasing anthropogenic demands on soils [1] there is growing need to seek for novel approaches to understand the relationships between the soil porous structure and specific soil functions. Recently [2-4], soil pore structure was described as a complex network of pores using spatially embedded varying fitness network model [2] or heterogeneous preferential attachment scheme [3-4], both approaches revealing the apparent scale-free topology of soils. Here, we show, using a large set of soil images of structures obtained by X-ray computed tomography that both methods predict topological similar networks of soil pore structures. Furthermore, by analyzing the node-node link correlation properties of the obtained networks we suggest an approach to quantify the complexity of soil pore structur

Aplicación de índices de vegetación para evaluar la falta de producción de pastos y montaneras en dehesas.

El ganado porcino ibérico aprovecha los recursos naturales de la dehesa mediante montanera, principalmente la bellota y los pastos existentes. La línea 133 de los seguros agrarios españoles recoge el seguro de compensación por pérdida de pastos, solo para bovino reproductor y de lidia, ovino, caprino y equino, no incluyen los cerdos en montanera. Emplea un Índice de Vegetación de la Diferencia Normalizada (NDVI) medido por satélite sobre pastos desarbolados. El objetivo es comprobar si se puede utilizar un índice de vegetación para estimar la producción de pasto y bellota. Se han tomado datos del aforo de montaneras desde 1999 al 2005, y del pasto en dehesas de Salamanca (Vitigudino), Cáceres (Trujillo) y Córdoba (Pozoblanco) durante 2010 al 2012. Con los datos de 2010 y 2011 se estableció una función de producción del pasto fresco en función del NDVI, mostrando un coeficiente de correlación de 0,975, altamente significativa. Los datos obtenidos en 2012 se utilizaron para validar la función de producción de pasto fresco. La comparación entre los valores observados y simulados para 2012 ha mostrado un coeficiente de correlación de 0,734. Como conclusión, el NDVI puede ser un buen estimador de la cantidad de pasto fresco en dehesas españolas

Mathematical modeling in soil science

Teaching in context can be defined as teaching a mathematical idea or process by using a problem, situation, or data to enhance the teaching and learning process. The same problem or situation may be used many times, at different mathematical levels to teach different objectives

Territorial plannnig in a river basin with high erosion level using multicriteria decision methods in cordoba province(argentine)

The erosion-sedimentation-flooding processes in large zones of Argentine are a critical problem that involve complex relationships with technological, economic, social and environmental cause-effect. The increasing of agricultural activities in new areas previously with forestry or pasture could produce irreversible environmental impacts. It is necessary to prepare a spatial plan taking into consideration, economic development, social cohesion, environmental quality and progressive desertification. Multicriteria decision models contribute to the elaboration of that plan and provide an inestimable aid to decision makers. The objective of this paper is to elaborate a multicriteria model applied to the La Colacha Basin (Cordoba-Argentine). La Colacha Basin has 416 km2, it is a representative basin of a dry-sub-humid area where agriculture practices are progressively increased. Ten alternatives have been evaluated combining: (a) Agro-forest-pastoral (ASP), Present use (ACT) e Intensive use (INT), (b) with or without Soil conservation (CS), y (c) with or without Hydrological arrangement of the basin (OH). There have been selected 13 criteria. Different Multi-criteria Decision Methods, both of traditional or developed by the authors, have been used

Fractal scaling of apparent soil moisture estimated from vertical planes of Vertisol pit images

Image analysis could be a useful tool for investigating the spatial patterns of apparent soil moisture at multiple resolutions. The objectives of the present work were (i) to define apparent soil moisture patterns from vertical planes of Vertisol pit images and (ii) to describe the scaling of apparent soil moisture distribution using fractal parameters. Twelve soil pits (0.70 m long × 0.60 m width × 0.30 m depth) were excavated on a bare Mazic Pellic Vertisol. Six of them were excavated in April/2011 and six pits were established in May/2011 after 3 days of a moderate rainfall event. Digital photographs were taken from each Vertisol pit using a Kodak™ digital camera. The mean image size was 1600 × 945 pixels with one physical pixel ≈373 μm of the photographed soil pit. Each soil image was analyzed using two fractal scaling exponents, box counting (capacity) dimension (DBC) and interface fractal dimension (Di), and three prefractal scaling coefficients, the total number of boxes intercepting the foreground pattern at a unit scale (A), fractal lacunarity at the unit scale (Λ1) and Shannon entropy at the unit scale (S1). All the scaling parameters identified significant differences between both sets of spatial patterns. Fractal lacunarity was the best discriminator between apparent soil moisture patterns. Soil image interpretation with fractal exponents and prefractal coefficients can be incorporated within a site-specific agriculture toolbox. While fractal exponents convey information on space filling characteristics of the pattern, prefractal coefficients represent the investigated soil property as seen through a higher resolution microscope. In spite of some computational and practical limitations, image analysis of apparent soil moisture patterns could be used in connection with traditional soil moisture sampling, which always renders punctual estimate

Soil resources and element stocks in drylands to face global issues

Drylands (hyperarid, arid, semiarid, and dry subhumid ecosystems) cover almost half of Earth’s land surface and are highly vulnerable to environmental pressures. Here we provide an inventory of soil properties including carbon (C), nitrogen (N), and phosphorus (P) stocks within the current boundaries of drylands, aimed at serving as a benchmark in the face of future challenges including increased population, food security, desertification, and climate change. Aridity limits plant production and results in poorly developed soils, with coarse texture, low C:N and C:P, scarce organic matter, and high vulnerability to erosion. Dryland soils store 646 Pg of organic C to 2 m, the equivalent of 32% of the global soil organic C pool. The magnitude of the historic loss of C from dryland soils due to human land use and cover change and their typically low C:N and C:P suggest high potential to build up soil organic matter, but coarse soil textures may limit protection and stabilization processes. Restoring, preserving, and increasing soil organic matter in drylands may help slow down rising levels of atmospheric carbon dioxide by sequestering C, and is strongly needed to enhance food security and reduce the risk of land degradation and desertification

Evaluación del riesgo medioambiental en sistemas agropecuarios

7 páginas, 5 figuras y 2 esquemasLas actividades agropecuarias, agricultura y ganadería, son motivo de consideración actual dentro de la investigación y valoración de riesgos ambientales debido a dos hechos relevantes: la utilización de plaguicidas y la generación de volúmenes importantes de desechos ganaderos. La generación de volúmenes de desechos ganaderos es una gran preocupación medioambiental y dado que existe poca investigación en la materia ha llevado a varios grupos de investigación a dedicar sus esfuerzos a este campo. El riesgo ambiental está basado en tres consideraciones: las características de toxicidad de la sustancia que se incorpora al medio, su comportamiento ambiental y su capacidad de contactar con un ser vivo (receptor biológico). Lo primero que salta a la vista es que estamos considerando una "mezcla compleja", sin embargo, los conceptos de riesgo son igualmente necesarios si pretendemos investigar "la probabilidad de que ocurra un daño por desechos ganaderos en el medio ambiente.CISA-INIA ValdeolmosETSI - Agrónomos U.P. MadridCentro de Ciencias Medioambientales- CSIC MadridPeer reviewe