The paper presents results of investigations whose aim was to determine the influence of different doses of farmyard manure, straw as well as EM-A microbiological vaccine on some selected physical and water properties of the arable-humic horizon of mineral soil. The experiment was established in controlled laboratory conditions. Combinations with two doses of farmyard manure and straw were investigated. Moreover, a combination with an additional microbiological vaccine application of effective microorganisms (EM) was also tested. The following properties were determined in the examined soil samples: texture, solid phase density, natural and hygroscopic moisture content, maximal hygroscopic capacity, soil density, porosity, filtration coefficient, water capacities at definite potentials of its binding by soil. It was found, among others that the solid phase density was modified only by the quantity and quality of the applied organic matter additives. Volumetric density was the lowest in the initial material and the addition of EM-A enhanced its value. The highest total porosity was obtained in the zero sample and the addition of EM-A reduced its value. In all the remaining combinations, the application of effective microorganisms deteriorated water-air conditions of the soil. Values of the filtration coefficient declined together with the increase in the proportions of organic matter and the addition of EM-A in individual combinations was found to reduce filtration velocity. Runs of water desorption curves depended very distinctly on the applied doses of farmyard manure and straw. The addition of EM-A preparation failed to affect this soil property. In the light of the obtained research results, its application in similar combinations appears to be not very effective or completely unjustified.