Topsoil Humus Reserve on Agricultural Lands Affected by Hydric Erosion. Hillslopes Scale Assessment in Central Romania

In the context of climate change and the high anthropogenic pressure on land, water erosion became a global issue, requiring increased attention from specialists and community members due to the agricultural implications. The process lead to irreversible changes in soil along the slope and to loses of organic matter and fertility. In this study, the topsoil total humus reserve (THR) from central Romania was evaluated. THR distribution along the slope was analyzed and the dependence of THR on the slope morphometry, soil features and type, on land with different types of agricultural management was tested. The results indicate a strong positive correlation between the THR and the humus content of the upper horizon and between the THR and the thickness of the soil horizon. Although the total humus reserve varies from one profile to another, a moderately significant negative correlation was found between THR and altitude, but the THR was not significantly influenced by the slope exposure. The relationship between THR and soil types and between THR and soil texture reveals significant differences. The humus reserve is significantly influenced by the type of land use; the highest average value of the humus reserve was found on arable land and the lowest absolute value was found on degraded pastures. This kind of study facilitates the identification of the most important controlling factors of carbon stock with direct implications for improving soil quality by suggesting appropriate anti-erosional measures, sustainable agricultural techniques, and land management at regional and local levels.