Soil Quality Index According to Diverse Land Use Systems Across Europe

Abstract

Soil quality index (SQI) can be an effective parameter to evaluate soil quality based on plant growth and ecosystem services at a large scale. According to the European Commission, around 60%-70% of the European soil is not healthy due to degradation and rapid conversion of land uses; however, detailed studies on soil quality according to different land uses in the entire Europe are very limited. We aimed to develop an SQI using the Land Use and Coverage Area Frame Survey (LUCAS) database for the existing croplands (230 samples), grasslands (53 samples), and woodlands (36 samples) to evaluate the overall soil quality across the continent. A total of five soil variables (sand, organic carbon, electrical conductivity, bacteria, and fungi) were selected for the minimum dataset based on principal component analysis from all 13 variables to avoid redundancy. The relationship between the developed SQI and climatic variables (precipitation and temperature) was also analyzed. We found that croplands had higher SQI (0.45 +/- 0.09) than grasslands (0.44 +/- 0.09) and woodlands (0.43 +/- 0.1), with no significant differences among the land uses (p > 0.05). The spatial analysis revealed higher SQI (> 0.46) in the central part of the EU and lower (< 0.46) in the northern and southwestern EU. The sub-categorical assessment of land uses showed that broadleaved and mixed woodland had better soil quality than the coniferous counterparts. The SQI showed a weak relationship with precipitation and temperature in all land uses, and it differs depending on climatic zones. Our findings also suggested that the agricultural management practices in cropland and better soil quality in grassland might buffer the influences of short-term variations in temperature and precipitation. We conclude that this EU-scale study of SQI provides a clear view of the soil quality status, which can also be effective for the policymakers to adopt sustainable management practices for improving soil quality.