The researchers studied how soil structure changes after being tilled and exposed to wetting and drying cycles. They used X-ray tomography to look at pore size and connectivity in nine Swedish soils. They found that total porosity decreased in most soils, with some shifting towards smaller pores. Soil surface porosity decreased significantly in some soils, especially those with higher silt content. The changes in pore size distribution were mainly influenced by the initial soil structure created during tillage.