2 resultados para Dynamic of nutrients
em Universidad de Alicante
Resumo:
Forest plantations have been extensively used to combat desertification. In drylands, harsh climate conditions and unfertile soils often preclude seedling establishment. The improvement in seedling quality by manipulating nutrient availability could contribute to increase planting success. However, morpho-functional traits defining optimum seedling quality in drylands, and the fertilization schemes to achieve them, are still under discussion. Several studies suggest that well fertilized seedlings may perform better than nutrient limited seedlings in these environments. However, recent works have shown opposite results. In this review, we discuss the concept of seedling quality in drylands based on an evaluation of the effects of nutrient manipulation on seedling morpho-functional traits and field performance. According to existing data, we hypothesize that nutrient-limited small seedlings may be better adapted to arid environments and unfavorable microsites, where access to water is uncertain and a conservative water use strategy may be advantageous. In contrast, in dry sub-humid areas, areas with deep soils, protected from excess radiation, and areas where irrigation is feasible, well-fertilized big seedlings with high root growth potential may have more chances of success. We discuss this theory in the context of the multiple objectives of dryland restoration and the environmental constrains posed by these areas, and identify knowledge gaps that should be targeted to test our hypothesis.
Resumo:
This is a case study that analyzes photographic documents of the social protest in Spain between 2011 and 2013. The analysis is qualitative and considers the use of space, the visual expression of the messages and the orientation toward the causes or effects of political, economic and social changes. Visual sociology allows us to appreciate, in the case of the Spanish Revolution, a dynamic of “reflexivity” unrecognizable from other research approaches. Two successive waves of social mobilization in response to two different shocks can be appreciated. The first is given by political corruption, unemployment and the threat to consumer society. The second shock is caused by the savage cuts in the Welfare State. Social mobilization is expressed differently in each phase, and the forms taken by the protests show how the class structure in post industrial society shapes the reactions to the crisis of the Welfare State.