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Improvement of water-air properties of eroded soils in a loess landscape after the application of agrohydrogel. The research was carried out in a fi eld experiment in eroded Haplic Luvisols developed from loess at a privately owned farm in Bogucin (51°20'N, 22°23'E) at the Lublin Upland. After spring wheat had been sawn, 9 plots with an area of 9 m 2 each, including 3 control plots, were marked out. AgroHydroGel was spread over in the doses of 1 gּkg -1 and 2 gּkg -1 (recalculated to dry soil) and mixed within the 0-5 cm layer of soil. AgroHydroGel is a cross-linked hydrophilic polyacrylamide copolymer with water absorption of 300-500 gּcm improved the majority of the water-air properties in the soil surface layer. The bulk density decreased signifi cantly whereas the maximum water capacity, saturated hydraulic conductivity, total porosity, content of macropores > 20 μm, actual air permeability and permeability at fi eld water saturation were signifi cantly higher. The polymer dose of 2 gּkg -1 was more effective, increasing signifi cantly also fi eld water capacity in the soils studied. The applied doses of the hydrogel did not change signifi cantly actual soil moisture, retention of water useful to plants, including retention of easily available water, and content of water-stable aggregates < 0.2 μm in diameter. A more benefi cial effect of AgroHydroGel on water-air properties of the eroded soils was found in August.

Assessment of soil structure of Luvisols developed from loess classified in various complexes of agricultural suitabilityAbstract: The objective of the study was the estimation of the aggregate size distribution and water stability of aggregates in Luvisols developed from loess, classified in three agricultural suitability complexes of soils used in Poland: very good wheat (1), good wheat (2) and deficient wheat complex (3). Soils classified in the very good wheat complex had a significantly higher content of air-dry aggregates with sizes in the range of 0.2510 mm than those classified in the good wheat and deficient wheat complexes. The aggregate size distribution of Ap horizons of soils classified in the very good wheat complex was assessed as highly favourable, and the composition of Ap horizons of soil from the good wheat and deficient wheat complexes as favourable. The aggregate size distribution of the subsoil in the depth of 2575 cm was assessed as favourable, while in the depth of 75100 cm as medium favourable. The soils classified in the very good wheat and good wheat complexes were characterised by significantly higher contents of stable aggregates with sizes of 0.2510 mm and 110 mm compared to the soils of the deficient wheat complex. Water stability of aggregates in the Ap horizons of soils classified in the very good wheat and good wheat complexes was estimated as good, and in the Ap horizons of soils of the deficient wheat complex as medium. Whereas, the water stability of aggregates in the Et, Bt, BC and C horizons was assessed as very poor. The reason of the deterioration of aggregate-size distribution and decrease of water-stable aggregate content with sizes of 0,2510 mm, especially in Luvisols classified in the deficient wheat complexes was accelerated soil erosion.

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