The effect of urban expansion on a range of soil properties, dependent on spatial patterns and land use change, around the city of Heraklion, Crete (Greece) with ArcGIS interpretation, and implications for potential soil management solutions

Modifications associated with land use can affect soil. With increasing urbanization around Heraklion in Crete, Greece, the city is extending towards rural areas in all directions, resulting in human conversion of unmanaged land to affected land use which includes concrete surfaces (residential/commercial areas, industrial areas and roads) and agricultural land. Therefore, the demands of soil quality for converted land use are becoming more and more significant.

The aim of this paper is to identify whether there is a change in soil properties and soil quality in relation to different land uses around Heraklion and explore the main causes for these changes. The study area included Heraklion and the surrounding rural area with a research area of 13km (east-west) x 7km (north-south). A total of 12 natural phryganic shrublands, 9 young olive groves, 36 old olive groves and 9 bare lands were the land use types subject to analysis.

This study examines whether there are spatial patterns between soil properties (and ultimately soil quality) in relation to different land use types. Due to the fact that if soil property is affected by land use, the soil property might have indirect effects on other soil properties, correlation between soil properties is taken in to account. The impact of different land use types on soil quality was evaluated by analysing 6 different soil properties: bulk density, organic matter, water content, electric conductivity, pH and nitrate.

The laboratory results from the soil properties were combined in order to create a soil quality index. Kruskal-Wallis was undertaken for statistical relationships between soil properties and land use types, where the only significant relationship was electrical conductivity (P value: 0.004). ArcMap was used to create 1 topographic map, 6 soil property maps, 3 chronologically different land use maps (1960, 1997 and 2016) and a soil quality map. Some soil property maps (organic matter-electrical conductivity, nitrate-electrical conductivity, bulk density- water content and nitrate-organic matter) showed significant correlations, while the soil quality map suggested that rural areas had better soil quality than urban areas.