A Monthly Double-Blind Peer Reviewed Refereed Open Access International e-Journal - Included in the International Serial Directories. International Research Journal of Natural and Applied Sciences (IRJNAS) ISSN: (2349-4077) 120 | Page International Research Journal of Natural and Applied Sciences Vol. 3, Issue 11, November 2016 Impact Factor- 5.46 ISSN:(2349-4077) © Associated Asia Research Foundation (AARF) Website: www.aarf.asia Email : editor@aarf.asia , editoraarf@gmail.com IMPACT OF THE BIOLOGICAL FERTILIZERS ON CHEMICAL INDEXES AND ENZYME ACTIVITIES OF SOILS AT CUCUMBERS Pavlina Naskova 1 , Bojka Malcheva 2 , Plamena Yankova 1 , Dragomir Plamenov 1 1 Department of Plant Production, Technical University – Varna, Bulgaria 2 Department of Soil Science, University of Forestry – Sofia, Bulgaria ABSTRACT 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 total 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 fertilizer products. The activity and of both enzymes may serve as a sensitive bioindicator at fertilized soils. KEYWORDS – Catalase, Cellulase, Fertilizer products, Nitrogen, Phosphorus, Potassium 1. INTRODUCТION During the last years the interest towards the greenhouse production of vegetables increases. It occupies hardly 0,4% from all areas, on which are grown vegetables. Thanks to its high intensity of production, the Bulgarian greenhouse production provides 15-17% from