The present experimental work is set as a vessel experiment in a non-heated greenhouse of department "Plant Production", Technical University-Varna, with purpose to be established the role of three biological products (Ekstrasol, Herbagreen, Life Bat Guano) and one mineral fertilizer (NPK) on chemical and enzyme indexes of soils at growing of greenhouse cucumbers variety Kiara F 1. It is established by the carried out analyzes, that the biological fertilizers leave the soil well stored with

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... l phosphorus and potassium, as the highest results are reported at usage of Ekstrasol. The highest values of total nitrogen are registered at the variants with mineral fertilizing. The catalase activity is higher at the combined fertilized soils with NPK + Herbagreen, Ekstrasol + Herbagreen and Life Bat Guano + Herbagreen in comparison with the controls and the samples, fertilized only with one product (NPK, Ekstrasol and Life Bat Guano). The bringing in of fertilizers increases the activity of the enzyme cellulase at all fertilized soils in comparison with the controls, as this tendency correlates with the increased content of nutrient elements nitrogen, phosphorus and potassium after the adding of the