The effect of slope on soil organic matter and on microbial communities under different soil management practices.

In Mediterranean regions, olive plantations are commonly located on steep 
slopes, leading to significant erosion. To mitigate soil loss, sustainable management 
practices often involve allowing natural vegetation cover to grow in the inter-tree 
spaces. 

To provide insights into the impact of different management forms on soil quality, we 
collected topsoil samples (0-15 cm) from an olive orchard with an 11% slope located in 
Southern Spain (Benacazón, Seville). Samples were taken along the slope of plots
managed with conventional tillage (CT) and with natural cover (NC). Additionally, soils
from the tree line, treated with herbicide (TL-Herb.), were included. To account for 
seasonality effects, sampling campaigns were conducted in autumn 2022 (following the 
dry season) and spring 2023 (after the rainy season). 

Soil organic matter content will be correlated with the management practices, slope 
location and microorganism abundance, determined through phospholipid fatty acid 
analysis (PLFA). Microbial respiration analysis will be also performed, using MicroResp
to assess microbial activity. The main hypothesis is that plots with vegetation cover will 
have higher SOM and total microbial biomass contents. We also expect an impact of 
slope location not only on the size of the microbial pool but also on the microbial 
biodiversity.