Agricultural crop productivity is closely linked to organic matter in soils, as organic matter increases the soil water holding capacity through its influence on soil structure and aggregation. To minimize the impact and costs of drought, soil needs to capture the rainwater that falls on it, store as much of that water as possible for future plant use, and allow for plant roots to penetrate and proliferate. Creating drought-resistant soil thus means to manage soil organic matter in order to enhance soil structural development. To study the effects of different organic matter additions to soil, a detailed analysis of the chemical composition and structure is necessary. The analytical challenge is in the complexity of the soil materials (different minerals provided by weathering associated with all organic materials of plant or microbial origin entering soils) and the fine spatial scales of these arrangements at the submicron scale and their relation to the soil water holding properties.
Our interdisciplinary project team will investigate the fate and structural association of specific organic soil amendments, by a new combination of long-term field experimental approaches, state-of-the-art soil analyses (solid-state 13C NMR spectroscopy) and high-end analytical (Raman microspectroscopy, stable isotope Raman microscopy and surfaceenhanced Raman scattering) approaches. With this strategy we will analyze the effect of organic matter amendments on the formation of soil structure and aggregation, and thus on the ability of soils to capture plant available water over periods of drought.