LAUSR

The aim of the study was to determine the shear strength of the soil-root layer obtained as a result of growth of cocksfoot ( Dactylis glomerata L.) on degraded soil enriched with the addition of a new zeolite substrate Z-ion. Measurement of shear strength for soil-root layers formed as a result of growth of a grass species (on degraded soil alone and on degraded soil with added Z-ion) was performed in a direct shear apparatus. The measurement results allowed determining parameters of equations describing the dependence of shear strength of studied soil-root layers on normal stress e.g. cohesion and internal friction coefficient. Under the experimental conditions, application of 1% v/v substrate addition to degraded soil induced development of cocksfoot root system which resulted in the significantly increased cohesion of soil-root layer (by 30%) as compared to that formed on degraded soil alone. The enhanced cohesion of the soil-root layer formed on soil enriched with Z-ion resulted in its significantly in - creased shear strength as compared to that of soil-root layer obtained on soil alone. Further research using higher doses of the Z-ion substrate (greater than 1% v/v) is needed to obtain the information at what dose ranges of the substrate one can expect even more intensive development of plant root systems and, consequently, further signifi - cant improvement in the shear strength of the soil-root layers.