Einfluss des Wassergehalts, des Eintrags von Wurzeln und gelöster organischer Substanz und räumlicher Unzugänglichkeit auf den C-Umsatz & Bestimmung der räumlichen Variabilität von Bodeneigenschaften

含水量、根系输入和溶解有机物以及空间交通不便对碳周转的影响

• 批准号: 233424527
• 负责人: Professor Dr. Bernard Ludwig
• 金额: --
• 依托单位: Institut für Bodenökologie (IBOE) (aufgelöst)
• 依托单位国家: 德国
• 项目类别: Research Units
• 财政年份: 2013
• 资助国家: 德国
• 起止时间: 2012-12-31 至 2015-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/233424527?language=en
• 关键词: Einfluss; des; Wassergehalts; Eintrags; von; Einfluss; des; Wassergehalts; Eintrags; von

It is well established that reduced supply of fresh organic matter, interactions of organic matter with mineral phases and spatial inaccessibility affect C stocks in subsoils. However, quantitative information required for a better understanding of the contribution of each of the different processes to C sequestration in subsoils and for improvements of subsoil C models is scarce. The same is true for the main controlling factors of the decomposition rates of soil organic matter in subsoils. Moreover, information on spatial variabilities of different properties in the subsoil is rare. The few studies available which couple near and middle infrared spectroscopy (NIRS/MIRS) with geostatistical approaches indicate a potential for the creation of spatial maps which may show hot spots with increased biological activities in the soil profile and their effects on the distribution of C contents. Objectives are (i) to determine the mean residence time of subsoil C in different fractions by applying fractionation procedures in combination with 14C measurements; (ii) to study the effects of water content, input of 13C-labelled roots and dissolved organic matter and spatial inaccessibility on C turnover in an automatic microcosm system; (iii) to determine general soil properties and soil biological and chemical characteristics using NIRS and MIRS, and (iv) to extrapolate the measured and estimated soil properties to the vertical profiles by using different spatial interpolation techniques. For the NIRS/MIRS applications, sample pretreatment (air-dried vs. freeze-dried samples) and calibration procedures (a modified partial least square (MPLS) approach vs. a genetic algorithm coupled with MPLS or PLS) will be optimized. We hypothesize that the combined application of chemical fractionation in combination with 14C measurements and the results of the incubation experiments will give the pool sizes of passive, intermediate, labile and very labile C and N and the mean residence times of labile and very labile C and N. These results will make it possible to initialize the new quantitative model to be developed by subproject PC. Additionally, we hypothesize that the sample pretreatment “freeze-drying” will be more useful for the estimation of soil biological characteristics than air-drying. The GA-MPLS and GA-PLS approaches are expected to give better estimates of the soil characteristics than the MPLS and PLS approaches. The spatial maps for the different subsoil characteristics in combination with the spatial maps of temperature and water contents will presumably enable us to explain the spatial heterogeneity of C contents.

众所周知，新鲜有机物的供应减少，有机物与矿物相的相互作用以及空间不可接受的性会影响下层土壤中的C种群。但是，稀缺，需要更好地理解每个不同过程对C隔离和改善地下土壤C模型的贡献所需的定量信息。对于下土壤中土壤有机物的分解速率的主要控制因素也是如此。此外，很少见到底土中不同特性的空间变化的信息。少数研究的研究是近乎和中间红外光谱（NIRS/MIR），具有地静力方法表明，可能会产生空间图，这些空间图可能显示出在土壤剖面中生物学活动增加的热点及其对C含量分布的影响。目标是（i）通过应用分馏程序与14C测量相结合，以确定不同分数中地下土壤C的平均停留时间； （ii）研究水含量的影响，13C标记的根的输入以及溶解的有机物和空间的不可接受性对自动缩影系统中C周转的影响； （iii）使用NIR和MIR确定一般土壤特性以及土壤生物学和化学特性，以及（IV）通过使用不同的空间插值技术来推断所测量的土壤特性和估计的土壤特性。对于NIRS/MIRS的应用，将优化样品预处理（风干与冷冻干燥的样品）和校准程序（改良的部分最小二平方（MPLS）方法与与MPLS或PLS相连的遗传算法）的方法将被优化。我们假设化学分馏与14C测量的结合应用结合使用，并且孵化实验的结果将使被动，中级，不稳定，不稳定和非常不稳定的C和N的池大小以及不稳定的不稳定和不稳定C和N的平均住宅时间。这些结果将使这些结果可以通过Subproph PC开发新的定量模型。此外，我们假设样品预处理“冷冻干燥”对于估计土壤生物学特征而不是空气干燥更有用。与MPLS和PL方法相比，GA-MPLS和GA-PLS方法有望提供更好的土壤特性估计值。与温度和水含量的空间图相结合的不同地产特征的空间图可能使我们能够解释C含量的空间异质性。