Calibración de sensores de humedad capacitivos usando redes neuronales

X Jornadas de Investigación de la Zona no Saturada del Suelo, Salamanca (España), 2011El estudio de la variabilidad espacial de la humedad del suelo a escala de parcela o cuenca agrícola requiere el uso de redes de sensores de humedad de bajo coste, que suelen mostrar una fiabilidad limitada y requieren de calibraciones específicas, especialmente en suelos con elevados contenidos en arcilla. El presente trabajo pretende plantear una calibración más fiable de sondas de humedad mediante un análisis mixto campo-laboratorio. Para la calibración de campo se dispone de datos gravimétricos; para la calibración en laboratorio se han usado columnas de suelo inalterado que tras ser saturadas fueron desecadas en un entorno controlado mientras se monitorizaba la evolución de su peso y la de su humedad volumétrica, medida con diferentes sondas capacitivas Decagon. Tras obtener curvas de secado y la relación entre la humedad gravimétrica y la volumétrica es posible realizar una calibración mejorada específica para cada tipo de suelo. Las redes neuronales son particularmente útiles para el modelado de procesos físicos y el ajuste de modelos. En este trabajo se propone el empleo de dichas herramientas para obtener calibraciones para las sondas analizadas en el tipo de suelo objeto de estudio. Los resultados muestran que dichas calibraciones permiten mejorar la precisión de las mediciones de humedad realizadas.The study of the spatial variability of soil water content at agricultural plot or catchment scales requires the use of low-cost soil water content sensor networks, which usually show a limited reliability and require specific calibrations, specially for soils with a high clay content. This work proposes a more reliable calibration of soil water content probes with a laboratory analysis. Minimally disturbed soil columns were saturated with water and dried in a controlled environment while monitorizing the evolution of their volumetric soil water content (with different capacitive Decagon Probes) and weights. After obtaining the drying curves and the relation between the volumetric and the measured gravimetric soil water contents it is possible to achieve an improved calibration specific for different kinds of soil. Neural networks are especially interesting for the modeling of physical processes and model adjustment. In this work, these tools were used in order to obtain improved calibrations for the analyzed probes in the studied soil type. Results show that this calibration improves the accuracy and pMinisterio de Ciencia e Innovación AGL2009 C03-03Junta de Andalucía AGR-478

Determination of agro-environmental zones in Spain and sensitivity to global climatic change

Póster presentado en la Conferencia EGU 2013, 07-12 Abril 2013, Viena, AustriaSoil has a key role in the regulation of carbon, water and nutrient cycles. Traditionally, agricultural soil management was oriented towards optimizing productivity. Nowadays, mitigation of climate change effects and maintaining long-term soil quality are evenly important. Developing policy guidelines for best management practices need to be site-specific, given the large spatial variability of environmental conditions within the EU. Therefore, it is necessary to classify the different farming zones that are susceptible to soil degradation. Especially in Mediterranean areas, this variability and its susceptibility to degradation is higher than in other areas of the EU. The objective of this study is therefore to delineate current agro-environmental zones in Spain and to determine the effect of global climate change on this classification in the future. The final objective is to assist policy makers in scenario analysis with respect to soil conservation. Our classification scheme is based on soil, topography and climate (seasonal temperature and rainfall) variables. We calculated slope and elevation based on a SRTM-derived DEM, soil texture was extracted from the European Soil Database and seasonal mean, minimum and maximum precipitation and temperature data were gridded from publically available weather station data (Aemet). Global change scenarios are average downscaled ensemble predictions for the emission scenarios A2 and B2. The k-means method was used for classification of the 10 km x 10 km gridded variables. Using the before-mentioned input variables, the optimal number of agro-environmental zones we obtained is 8. The classification corresponds well with the observed distribution of farming typologies in Spain. The advantage of this method is that it is a simple, objective method which uses only readily available, public data. As such, its extrapolation to other countries of the EU is straightforward. Finally, it presents a tool for policy makers to assess the impact of global change on farming systems and to plan soil conservation measures

Soil Salinity Patterns in an Olive Grove Irrigated with Reclaimed Table Olive Processing Wastewater

The agricultural use of saline table olive processing wastewater enables the implementation of closed water cycles in this socioeconomically important industry for rural southern Spain and relieves environmental, economic, and legal burdens. To allow growers to evaluate and guarantee adequate long-term soil and plant conditions when irrigating with such regenerated wastewaters, efficient soil monitoring strategies are needed. Field-scale monitoring with electromagnetic induction sensing, after one (2013) and five years (2017) of irrigation with regenerated wastewater with average electrical conductivity (EC) near 6 dS m−1 in an olive orchard in southern Spain, showed accumulation of highly conductive material in the subsoil in relation to local topography and soil characteristics. Laboratory analysis of the soil water revealed strongly varying patterns of EC during the growing season and across the olive grove, which were attributed to dilution and concentration effects due to rainfall and evaporation, respectively. Visual inspection and leaf analyses revealed no negative effects on the olive trees. Apparent electrical conductivity (ECa), measured in between the tree rows in 2013, showed a linear relationship with surface soil EC1:5 under the drippers and allowed identification of areas with high ECa in the low elevation zones of the farm, due to the presence of shallow perched saline water tables. A second ECa measurement in 2017 showed similar spatial ECa patterns and was used to estimate the distribution of soil EC across the soil profile using inversion software, although no unique field-wide relationships with soil properties could be inferred, possibly as a consequence of spatially variable soil clay and water contents, due to the influence of the topography. Despite the implementation of a more conservative irrigation strategy since 2015, results showed that the salinity has increased since 2013 in about 15% of the study area, with the largest increments in the deepest horizons

A meta-analysis of the effects of agricultural management on soil physical quality for different farm typologies across Europe

Póster presentado en la Conferencia EGU 2014, 27 Abril - 7 Mayo 2014, Viena, Austri

Unión Europea, agricultura y manejo sostenible: Proyecto CATCH-C

Póster presentado el Día de la Conservación del Suelo 201

Some problems of the determination of best management practices to maintain the quality of agricultural soils

Póster presentado en la Conferencia ELS 2014, 22-25 Septiembre 2014, Bari, ItaliaIn spite of the great effort of scientific research exploring the influence of agricultural practices on soil quality, many aspects remain unclear, possibly precluding a more general adoption of the best management systems by farmers and land use planners. Among other causes of this knowledge gap, the wide variety of agricultural practices due to different climates, landforms, soils, and crop types make hard to find either a general best management system or at least common rules of larger applicability. Nevertheless the more important problem is that we usually consider soil as an invariant entity which does not change, or if it does, its changes are controlled. The purpose of this report is the discussion of the results of a meta-analysis of the effects of agricultural management practices on physical aspects of soil quality, throughout the published research data of countries of the central and western part of the European continent. Soil physical quality was evaluated through several indicators which were evaluated in the research reports found. The indicators were: bulk density, resistance to penetration, stability of aggregates, permeability and water and sediment yield. The results indicate that there are agricultural practices which could be classified as convenient, although their possible advantages are not always evident, as, for instance, direct drilling as compared to conventional tillage, where the farm operations induce a certain compaction not always alleviated in absence of tillage. To further explore some of the results, the evolution of some properties of a clay soil subject to a long term experiment in dry farming conditions in southern Spain is considered. The evolution of the soil properties must be taken into account, for a more precise evaluation of the efficiency of management practices

Carbon fractions and enzymatic activities in two cultivated dryland soils under conservation tillage

Abstract Long-term soil management experiments are expected to provide important information regarding sustainable crop production systems. In this study we evaluated the long-term effect of conservation tillage (CT) on biological properties in two different textured soils [Entiso

Evaluation of soil salinity and sodicity using electromagnetic conductivity imaging

Trabalho apresentado em EGU General Assembly 2021, 19–30 Abril 2021, onlineinfo:eu-repo/semantics/publishedVersio