Formiguer Soils The Mediterranean analogue to terra preta de Indio in the humid tropics?

由于全球变暖、土壤退化、世界人口增加和相关的粮食安全等全球问题悬而未决，严重受人类活动影响的土壤正变得越来越重要。以湿润热带的Terra Preta deñndio为例，人为土几百年后就可以蕴藏着巨大的养分和土壤有机质储量。然而，只有少数人为土进行了像Terra Preta那样深入的研究。一个有趣的例子是地中海加泰罗尼亚(西班牙)旨在提高土壤肥力的形式施肥技术。这种方法是基于厚厚的土壤覆盖下成堆的生物质碳化。燃烧后，加热的土壤覆盖物、灰烬、木炭和极有可能也是粪便被分布并并入土壤中。与周围未处理的土壤相比，得到的土壤仍然含有大量的宏观可见的木炭颗粒，土壤颜色深，土壤水分好，土壤动物活跃。该项目的一个关键问题是，在多大程度上，格陵兰土壤的投入材料和性质与Terra Preta deñndio相当，从而与其地中海类似物和地中海地区可持续土地利用模式相媲美。该项目使用最先进的方法重点解决三个主要问题。首先，将使用放射性碳测年(14C)、磷和氮同位素(D15N)分析以及分子标记来重建土地使用历史，以识别和量化木炭(黑碳)和粪便物质(斯坦醇和胆汁酸)。施肥量对土壤性质的影响将取决于与未处理的相邻土壤相比的土壤基本特性。在集约化土壤耕作条件下，木炭性质的长期变化仍然知之甚少。因此，第二个主题讨论了新鲜和陈化的木炭在土壤中的化学性质和可能的稳定机制，除了化学阻力外，这些机制可能导致其在土壤中的长期稳定。木炭的元素组成(C、N、O、H和O)以及黑炭的质量和数量将为深入了解木炭的形成过程(燃烧强度)和木炭的顽固性提供更深入的了解。结合显微镜和扫描电子显微镜、傅立叶变换红外光谱、X射线光电子能谱和薄片等光谱技术，可以确定土壤中木炭化学性质的变化。该项目的第三个主题集中于施肥法对微生物生物量和微生物群落结构的影响。氨基糖、胞壁酸和PLFA将作为真菌和细菌的标志物。

Soils heavily influenced by human action are increasingly gaining in importance because of unsolved global issues such as global warming, soil degradation, increasing world population and related food security. As shown by the example of terra preta de Índio in the humid tropics, Anthrosols can contain tremendous nutrient and soil organic matter stocks after several hundred years. However, only few Anthrosols are comparably intensive investigated than terra preta. An interesting example is the formiguer fertilization technique in the Mediterranean Catalonia (Spain) aiming an increasing soil fertility. The method is based on carbonization of piles of biomass under a thick soil cover. After burning, the heated soil cover, ash, charcoal and highly probable also dung were distributed and incorporated into the soil. The resulted soils still contain high amounts macroscopically visible charcoal particles, are dark in soil colour, having a good soil moisture and active soil fauna, which is in contrast to surrounding non-treated soils. In how far the input materials and properties of the formiguer soils are comparable to terra preta de Índio and thus its Mediterranean analogue and model for sustainable land use in Mediterranean regions, is a key question of the project. The project focuses three main issues using state-of-the-art methods. First, land use history will be reconstructed using radiocarbon dating (14C), phosphorous and nitrogen isotope (d15N) analysis combined with molecular markers for identification and quantification of charcoal (black carbon) and faecal matter (stanols and bile acids). The impact of formiguer fertilization on soil properties will be determined by soil basic characterisation of formiguer soils compared with non-treated adjacent soils. Changes of charcoal properties in the long-term under intensive soil cultivation are still poorly understood. Thus, the second subject addresses the chemical properties of fresh and aged charcoals in formiguer soils and possible stabilization mechanisms, which may lead, beside chemical recalcitrance, to its long-term stabilization in soils. Elemental composition of charcoal (C, N, O, H and O) as well as the quality and quantity of black carbon will provide deeper insights in charcoal formations process (fire intensity) and recalcitrance of charcoals. Changes of chemical properties of charcoals exposed in soil will be determined by combining microscope and spectroscope techniques such as SEM-EDS, FTIM, XPS and thin sections. The third subject of the project focusses on the impact of the formiguer fertilization technique on microbial biomass and microbial community structure. Amino sugars, muramic acid and PLFA will be used as marker for fungi and bacteria.