Long-Term water stress and drought assessment of Mediterranean oak savanna vegetation using thermal remote sensing

Drought is a devastating natural hazard that is difficult to define, detect and quantify. The increased availability of both meteorological and remotely sensed data provides an opportunity to develop new methods to identify drought conditions and characterize how drought changes over space and time. In this paper, we applied the surface energy balance model, SEBS (Surface Energy Balance System), for the period 2001 2018, to estimate evapotranspiration and other energy fluxes over the dehesa area of the Iberian Peninsula, with a monthly temporal resolution and 0.05° pixel size. A satisfactory agreement was found between the fluxes modeled and the measurements obtained for 3 years by two flux towers located over representative sites (RMSD = 21 W m-2 and R2 = 0.76, on average, for all energy fluxes and both sites). The estimations of the convective fluxes (LE and H) showed higher deviations, with RMSD = 26 W m-2 on average, than Rn and G, with RMSD = 15 W m-2. At both sites, annual evapotranspiration (ET) was very close to total precipitation, with the exception of a few wet years in which intense precipitation events that produced high runoff were observed. The analysis of the anomalies of the ratio of ET to reference ET (ETo) was used as an indicator of agricultural drought on monthly and annual scales. The hydrological years 2004/2005 and 2011/2012 stood out for their negative values. The first one was the most severe of the series, with the highest impact observed on vegetation coverage and grain production. On a monthly scale, this event was also the longest and most intense, with peak negative values in January February and April May 2005, explaining its great impact on cereal production (up to 45 % reduction). During the drier events, the changes in the grasslands and oak trees ground cover allowed for a separate analysis of the strategies adopted by the two strata to cope with water stress. These results indicate that the drought events characterized for the period did not cause any permanent damage to the vegetation of dehesa systems. The approach tested has proven useful for providing insight into the characteristics of drought events over this ecosystem and will be helpful to identify areas of interest for future studies at finer resolutions

Condicionalidad reforzada a través de las cubiertas vegetales en olivar. Opinión de los agricultores

En el cultivo del olivar, en la última década, se ha implantado y extendido el uso de cubiertas vegetales como práctica cultural. El empleo de cubiertas vegetales en olivar se asocia a una multitud de efectos ambientales positivos y por tanto la implementación de estas en los olivares ha sido objeto de ayudas específicas en las medidas agroambientales de diferentes programas de desarrollo rural de Andalucía a partir del año 2000. Sin embargo, según los datos de la encuesta sobre Superficies y Rendimientos Cultivos del Ministerio de Agricultura, Pesca y Alimentación (Esyrce) las cubiertas vegetales en olivar sólo se emplean en alrededor de un 29% del total de la superficie del olivar andaluz. El objetivo de este trabajo es conocer la opinión de los agricultores con respecto a la puesta de cubiertas vegetales. Por ello se realizan 200 encuestas a olivareros y se determinan los factores de bloqueo y propiciadores a las mismas. Entre ellos, se analiza el impacto de una condicionalidad reforzada que obligue a los agricultores a usar cubiertas vegetales.El presente estudio ha sido financiado por el proyecto PR.AVA.AVA2019.031 cofinanciado al 80% por el Fondo Europeo de Desarrollo Regional, dentro del Programa Operativo FEDER de Andalucía 2014-2020

A Survey on Farmland Crop Information Acquisition

International audienceThe farmland crop information is the important foundation of developing fine agricultural practice. Crop information acquisition technologies have become the most effective means to increasing crop production and improving crop quality. In this paper, on the basis of introducing the characteristics of farmland crop data, different farmland crop information acquisition methods are surveyed in detail, sections need to be improved of these methods and related core technologies will be discussed. At last, this paper gives a table about crop information acquisition technology and sensing instrument systems applied in different levels (individual level, area level and wide-area level)