Search

Knowledge about the relative impact of climate and socio-economic factors on agriculture is still not well known as they change in space and time. Social researchers stress the role of endogenous (societal, economical, etc.) factors whilst physical/natural scientists focus on the role of climate on land use and land cover change, but the latter do not usually focus on human dynamics. Through the analysis of proxies of land cover, sediment yield (erosion) and salinity changes from sediments in a fluvial wetland in central Spain and documentary evidence collected from the 16th century onwards, it becomes clear that climate impact on farming has changed during this period. Thus, until ca. 1725 CE, agriculture production in central-southern Spain followed the cycles and trends of rainfall at the annual, multiannual and decennial time scales. From that time onwards, production began to show discrepancies with climate, with high production cycles associated with dry periods being common and a sustained productivity that was independent of climate trends and it must be related to socio-economic changes. This change from climate-driven to human-driven agriculture can be seen in other areas of the Iberian Peninsula but at different times that vary from the first half of the 17th century until the first half of the 18th century. These different times can be attributed to diachronous changes in the Little Ice Age phases and local and regional differences in economic factors (such as proximity to commercial routes, development of markets) and their evolution, as supported by the different information sources., Departamento de Geodinámica, Estratigrafía y Paleontología, Universidad Complutense de Madrid, España, Museo Comarcal de Daimiel, España, Instituto Geológico y Minero de España, España, Departamento de Geología, Geografía y Medio Ambiente, Universidad de Alcalá de Henares, España, Centro de Estudios y Experimentación de Obras Públicas, España

Human settlements around the fluvial wetland of Las Tablas de Daimiel (central Spain) have been related to the water availability in this area for nearly 5500 years; however the relationship of the hydrology of the wetland to climate change remains uncertain. Whilst archaeological and pollen data provide contradictory arguments, statistical empirical mode decomposition of geochemical data from core S-1 reveals arid periods ca. 1.8 cal. ka BP, ca. 3.3 cal. ka BP and ca. 5.5 cal. ka BP between which periods both Bronze Age and Iberian-Roman settlements developed. These periods can be identified in other records of the Iberian Peninsula and around the western Mediterranean. Comparison of these records points to a complex spatial pattern that evolved in time and, despite a number of forcings (volcanism, solar activity, atmosphere-ocean interactions) being invoked to explain such periods, there is no clear mechanism to explain their spatial pattern and the changes that have taken place since 2.5 ka BP., Departamento de Estratigrafía, Universidad Complutense de Madrid, España, Instituto Geológico y Minero de España, España, Museo Comarcal de Daimiel, España, Centro de Estudios y Experimentación de Obras Públicas, España

Con el propósito de investigar el valor nutritivo de cuatro pastas de soya mexicanas (Guanajuato, Veracruz, Hidalgo y Nuevo León), se realizaron dos experimentos. Las pastas de soya, analizadas previamente a los experimentos, resultaron dentro de los parámetros esperados para proteína cruda, perfil de aminoácidos, actividad urásica y solubilidad de la proteína. En el experimento 1 se utilizaron las pastas de soya como fuentes suplementarias de proteína en dietas sorgo + soya para pollos durante 42 días; los resultados indicaron que para ganancia de peso (2 057, 2 004, 2 078 y 1 978 g), consumo de alimento (3 860, 3 763, 3 666 y 3 498 g) y conversión alimentaria (1.87, 1.88, 1.76 y 1.77) no se detectaron diferencias (P 0.05) entre las cuatro pastas de soya. En el experimento 2 se determinó la energía metabolizable verdadera (EMV) con gallos Leghorn con el método de alimentación precisa en las cuatro pastas de soya, los resultados (2 450, 2 384, 2 430 y 2 290 Kcal/ kg) fueron, en promedio, 2 388 kcal/kg, sin diferencia (P 0.05) entre las pastas. De acuerdo con los resultados obtenidos del presente trabajo, se puede concluir que no existió diferencia en la calidad nutrimental entre las pastas de soya evaluadas con base en la prueba de comportamiento productivo en pollos de engorda y la determinación de EMV.

Facultad de Medicina Veterinaria y Zootecnia