The biodiversity is a core value in all ecosystems. The nitrogen (N) addition in the form of N fertilizers has effect to a wide variety of fauna living in soils. N losses from arable land should tend not only to cause water eutrophication, but also lower soil nutrient stocks and decreasing soil fertility. This study determined the effect of N soil content in conventional tillage agro-ecosystem on the soil fauna diversity in grass stripes under the sloped arable land. My objective here is to observe soil faunal taxa living in grass filter strips. The goal of this work is to describe the relationship of soil fauna to the nitrate (NO₃^-) content runoff from fields and captured in grass filter strips. The field work was carried out during period from May until June 2013, for soil fauna investigation the extraction in Berlese — Tullgren funnels were used. Nitratenitrogen (NO₃-N) was extracted from air-dried sieved soil using a 2 M KCl solution. Altogether 2,020 specimens representing 19 arthropod groups were found in twenty study sites. Most abundant taxa found practically in each of sampling site were Collembola, Acari and the suborder of Oribatid mites. Statistical evaluations revealed that the effect of NO₃^- concentration in the soil on the average value of the total edaphic individual numbers was statistically significant; the same applies for the abundance of Acari mites. No significant results were find for the Oribatid mites and the Collembola family; however, there was a clear trend of increasing abundance with increasing concentrations of NO₃^-.