Land use effects on carbon and nutrient fluxes in soils

Land-use and management influence the coupled carbon and nutrients cycles in soils. However, studies that investigate carbon and nutrient cycling in multiple land-uses over multiple study regions with distinct environmental conditions and across broad management gradients are scarce. Therefore, many questions regarding management, biotic and abiotic effects on carbon and nutrient cycling, remain open in real-world ecosystems. Some of these research questions are: i) how forest properties affect soil respiration: through their effects on soil properties or on climatic conditions?, ii) how grassland management influences soil respiration, and that is the role of plant diversity? and iii) what is the relative importance of direct and indirect effects of grassland management on nutrient leaching, and how are the indirect effects mediated by soil, plant and microbial properties? In this thesis, I measured in-situ soil respiration and nutrient (nitrate, ammonium, phosphate and sulphate) leaching in 150 forests and 150 grasslands over three temperate regions in Germany. In-situ soil respiration was measured with soda-lime method as single measurements over long periods (3-7 days), in early summer in 2018 and 2019. Nutrient leaching was determined at 10 cm soil depth with a resin method as the cumulative downward flux over a year (from spring 2018 to spring 2019). The main objectives of my Thesis were to: i) determine management effects on these two major soil functions, ii) determine their main biotic and abiotic drivers, and iii) compare these carbon and nutrient fluxes between the two land-use types.