Effect of Land Use on Soil Fertility in Galicia Based on LUCAS Data

The impact of land use on soil can be determined through the land-use information provided by the LUCAS database, which makes it possible to understand the processes resulting from the establishment of broadleaves, conifers, permanent grasslands, and shrublands. Using this database shows that, in the case of Galicia, there is a negative relationship between organic matter content and pH—something expected for the Galician region. Galicia is the area with the highest forest growth potential in 
Europe, which ensures the incorporation of organic matter into the soil. However, the rate of mineralization of that organic matter, and therefore its ability to be mineralized or remain stored in the soil, depends on pH. Under very acidic conditions, organic matter—and therefore organic carbon—tends to accumulate in the soil because microbial processes slow down. 
Nevertheless, as this pH increases, organic matter content decreases due to the activation of mineralization rates. Land use affects the main chemical components of soil health. Organic matter and nitrogen, which vary in parallel in multivariate 
analysis, show lower levels in permanent grasslands compared with shrublands. Conversely, P levels and pH in water are higher in shrublands compared with permanent grasslands. This can be explained by management practices, since permanent grasslands are typically fertilized with phosphorus and limed, unlike more forest related land uses. As mentioned earlier, liming reduces organic matter and therefore nitrogen related land uses.