Soil aeration - the key factor of oak decline?

这是一种“复杂的疾病”。由于其模糊性，这一结果很难被证伪。致病真菌的重大贡献并非没有争议，因为主要致病作用尚未得到证实(Johnsson，2004)。我们的出发点是Gairtig等人的研究。(2002)，世卫组织发现，在巴登-符腾堡州28个橡树林的空间整合水平上，橡树健康症状与土壤通气性显着相关。过去几十年，栎林土壤结构的大规模变化可以归因于伐木机械化(Vossbrink和Horn，2004)以及酸化土壤中蚯蚓活动的减少。在拟议的项目中，我们希望在三维空间中建立根与通风相关参数之间的关系。这一繁琐的过程是必要的，因为土壤-空气通道是高度异质的，通过这种方式形成了三维图案。这使得一维模型效率低下。通过在三维空间中对土壤空气通道进行建模，我们想要检验曝气假说。生根的重要指标是细根丛生、坏死或空间歧视。通过在同一空间分辨率下同时评估土壤化学参数和土壤物理参数，可以检验不同的假设。作为建模工具，将使用点统计、非参数回归(GAM)和瞬时气体扩散方程的三维解。

it is a „complex disease . This result can hardly be falsified because of its fuzziness. A significant contribution of pathogenic fungi is not without controversy, because the primary pathogenicity is not proven (Johnsson, 2004). Our starting point is the research of Gaertig et al. (2002) who found that on a spatial integration level of 28 oak stands in Baden-Wuerttemberg the symptoms of oak health are significantly correlated with soil aeration. Large-scale changes of soil structure in oak stands during the last decades can be attributed to the mechanization of logging (Vossbrink and Horn, 2004) as well as to a decrease of earthworm activity in acidified soils. In the proposed project we want to establish a relationship between roots and aerationrelevant parameters in a three-dimensional space. This laborious procedure is necessary because the soil-air access is highly heterogeneous and by this way forms a three-dimensional pattern. This makes one-dimensional models inefficient. By modelling the soil air access in a three-dimensional space we want to test the aeration hypothesis. Important indicators of rooting are clustering of fine roots, necrosis, or space discrimination. By assessing simultaneously soil-chemical and soil-physical parameters in the same spatial resolution, alternative hypotheses can be tested. As modelling tools point statistics, non parametric regression (GAM), and a three dimensional solution of the instationary gas-diffusion equation will be used.