The paper deals with the influence of conservation tillage upon chemical properties, nitrogen application, biological properties and plant diseases. As regards soil chemical properties, it should be stressed that they are mainly influenced by fertilization. They naturally depend on soil tillage, which has a dominant effect on the distribution of nutrients in the tilled layer. This primarily applies to phosphorus and potassium whereas nitrogen behaves in a specific way due to its specific dynamics in soil. Biological activity is also associated with conservation tillage, notably with regard to earthworms. It also affects the microbiological state of soil. The number of microorganisms changes under the influence of conservation tillage, especially if soil is not turned over. Accumulation of large amounts of plant residues in different forms of conservation tillage creates conditions favouring spread of plant diseases. Integral plant protection against pests greatly relies on resistant cultivars, but also on chemical and biological methods.