Soil erosion and changes in the physical properties of Lithuanian Eutric Albeluvisols under different land use systems

The investigations aimed to: 1) evaluate water erosion rates on undulating slopes in Lithuania under different land use systems; 2) study changes in soil physical properties on the differently eroded slopes; and 3) better understand relationships between soil physical properties and soil erodibility. Research data were obtained on loamy sand and clay loam Eutric Albeluvisols located on the undulating hilly relief of the Zemaiciai Uplands of Western Lithuania. The results of 18 years of water erosion investigations under different land use systems on slopes of varying steepness are presented. Attention is focused on changes in soil physical properties in relation to soil erosion severity. Measured water erosion rates in the field experiments were: 3.2-8.6 m(3) ha(-1) yr(-1) under winter rye, 9.0-27.1 m(3) ha(-1) yr(-1) under spring barley and 24.2-87.1 m(3) ha(-1) yr(-1) under potatoes. Perennial grasses completely prevented water erosion, while erosion-preventive grass-grain crop rotations (67% grasses, 33% cereal grains) decreased soil losses by 75-80% compared to the field crop rotation, containing 17% tillage crops (potatoes), 33% grasses and 50% cereal grains. The grain-grass crop rotation (33% grasses and 67% cereal grains) decreased soil erosion rates by 23-24%. The percentage of clay-silt and clay fractions of arable soil horizons increased, while the total soil porosity and moisture retention capacity decreased with increased soil erosion. Phytocenoses, including sod-forming perennial grasses and grass-grain crop rotations, led to changes in the physical properties of eroded soils; soil bulk density decreased and percentage total porosity and moisture retention capacity increased. The grass-grain crop rotations increased the water-stable soil structure (measured as water-stable soil aggregates) by 11.03 per cent units and sod-forming perennial grasses increased aggregate stability by 9.86 per cent units compared with the grain-grass crop rotation on the 10-14 degrees slope. Therefore, grass-grain crop rotations and sod-forming perennial grasses decreased soil erodibility and thus could assist both erosion control and the ecological stability of the vulnerable hilly-undulating landscape.