Mapping rootable depth and root zone plant-available water holding capacity of the soil of sub-Saharan Africa

In rainfed crop production, root zone plant-available water holding capacity (RZ-PAWHC) of the soil has a large influence on crop growth and the yield response to management inputs such as improved seeds and fertilisers. However, data are lacking for this parameter in sub-Saharan Africa (SSA). This study produced the first spatially explicit, coherent and complete maps of the rootable depth and RZ-PAWHC of soil in SSA. We compiled geo-referenced data from 28,000 soil profiles from SSA, which were used as input for digital soil mapping (DSM) techniques to produce soil property maps of SSA. Based on these soil properties, we developed and parameterised (pedotransfer) functions, rules and criteria to evaluate soil water retention at field capacity and wilting point, the soil fine earth fraction from coarse fragments content and, for maize, the soil rootability (relative to threshold values) and rootable depth. Maps of these secondary soil properties were derived using the primary soil property maps as input for the evaluation rules and the results were aggregated over the rootable depth to obtain a map of RZ-PAWHC, with a spatial resolution of 1 km2. The mean RZ-PAWHC for SSA is 74 mm and the associated average root zone depth is 96 cm. Pearson correlation between the two is 0.95. RZ-PAWHC proves most limited by the rootable depth but is also highly sensitive to the definition of field capacity. The total soil volume of SSA potentially rootable by maize is reduced by one third (over 10,500 km3) due to soil conditions restricting root zone depth. Of these, 4800 km3 are due to limited depth of aeration, which is the factor most severely limiting in terms of extent (km2), and 2500 km3 due to sodicity which is most severely limiting in terms of degree (depth in cm). Depth of soil to bedrock reduces the rootable soil volume by 2500 km3, aluminium toxicity by 600 km3, porosity by 120 km3 and alkalinity by 20 km3. The accuracy of the map of rootable depth and thus of RZ-PAWHC could not be validated quantitatively due to absent data on rootability and rootable depth but is limited by the accuracy of the primary soil property maps. The methodological framework is robust and has been operationalised such that the maps can easily be updated as additional data become available

El accidente de trabajo in misión: legislación jurisprudencia española

The concept of occupational accident in Spain is included within the broader one occupational injury and encompasses any damage resulting from working, being connected, caused or aggravated by it. A basic aspect is the causality relationship between injury and developed work, that means it can be as a consequence or for the occasion of the work. The accident in mission term refers to those accidents occurred to the worker in the performance of a mission entrusted by the employer in a place different from their usual work, or on the way having to go. Its consideration can be controversial in cases of traumatic or sudden events, specially cardiovascular events, and even more in those cases of biological infection of a worker displaced to an endemic area. The Spanish Jurisprudence has been restricting the aspects related to working time when talking about accidents in mission. A greater international collaboration and the settle of homogeneous criteria should be taken in order to achieve improvements in labour risk prevention.El concepto de accidente de trabajo en España se engloba dentro del más amplio de daño laboral e incluye cualquier alteración de la salud relacionada, causada o agravada por condiciones laborales. Un aspecto básico es la relación de causalidad entre lesión corporal y trabajo desarrollado, que puede ser por consecuencia o con ocasión del trabajo. El accidente de trabajo in mision hace referencia al ocurrido al trabajador en el desempeño de una misión encomendada por el empresario en un lugar distinto al de su trabajo habitual, o en el trayecto que tenga que recorrer. Resulta controvertido para eventos traumáticos o súbitos, especialmente cardiovasculares, y más en contagio biológico de un trabajador desplazado a zona endémica.La Jurisprudencia Española ha ido restringiendo los aspectos relativos a tiempo de trabajo en accidentes in mision y sería recomendable mayor colaboración internacional y criterios más homogéneos en todos los países en materia preventiva