Research Journal of Agricultural Science, 42 (1), 2010 39 IMPACT OF CONVENTIONAL AGRICULTURE ON SOIL ENVIRONMENT - FIELD STUDY IN TWO AREAS OF SA AGROTERRA AGIGEA, CONSTANŢA Irina CALCIU 1 , Sorin Liviu ŞTEFĂNESCU 1 , Elisabeta DUMITRU 1 , Monica DUMITRAŞCU 1 1) National Research and Development Institute for Soil Science, Agrochemistry and Environment Protection – RISSA Bucharest, Marasti bld. No. 61, Bucuresti, Corresponding author: irinacalciu@yahoo.com Abstract: The paper attempts to assess the impact of some conventional agricultural practices upon physical, chemical and biological soil state within two areas of SA Agroterra Agigea, located in Constanta county. Two expeditionary studies were organized in fields under relatively different agricultural technological systems application applied over a long time and benefiting of a consistent agro-environment history record. The investigated areas are covered by Chernozems aged on loess deposits. The soil from the first site (A19) has a medium texture, being medium loam, whilst the soil from the second site (A 821) has a clayey texture being medium clayey loam. The sampling was done in 2008, and a wide range of laboratory analyses were performed in order to evaluate soil physical (compactness, water permeability, water retention and availability, soil structure aggregates hydro-stability), chemical (reaction-pH in water, total nitrogen, available phosphorus and potassium content) and biological (quantity and diversity of bacterium microflora) state. The values of the physical indicators analyzed emphasized that the studied soils have a moderately favourable hydric regime, a slightly layering trend and a a high risk for destructuration – due to both natural environmental features as well as the continuing intensification of the intensive agricultural technologies applied. From chemical point of view, the soils reveal a weak- alkaline reaction, a low (A821) to moderate (A19) organic matter contents, generally a moderate supply with crop nutrients (nitrogen, phosphorus, potassium). The microbiological data show a satisfactory level of activity in the soil. Key words: conventional agricultural technology, soil state, impact INTRODUCTION S.A. Agroterra Agigea is located in Constanta county, that takes part of South Dobrogea tableland. From the total area of the Dobrogea region, 568300 thousands ha are under agricultural use, 487300 ha being arable land. As a result of the geographic location and of the geological structure, Dobrogea region has a diversity of geomorphological units: north and south Dobrogean tablelands, Dobrogean beach and Danube Delta. The south Dobrogean tableland is a tipic platform with a relatively low absolute altitude. The soils within this area have various genetic and environment conditions and a diveristy related to suitability for different agricultural crops. Within Dobrogea region five soil classes are spread: Protisoils, Cernisoils, Hydrosoils, Salsodisoils and Antrisoils, that are aged mainly on loess deposits. 80 % of the total agricultural area is covered by Cernisoils (Kastanozioms and Chernozems). These type of soils have a high productivity and are well supplied with crop nutrients. The main limiting factors within the agricultural land use consists of the risk for drought and aridization, the low workability potential and erosion. These negative factors that affect the soil productivity might be intensified by the conventional agricultural systems applied under unappropriate conditions, that lead to excessive soil loosening, faster mineralization of organic matter and soil aggregate destructuration. Research in field related to the different soil agricultural technologies use has a long tradition in our country. CHIRITESCU ARVA (1923) quoted by E. DUMITRU (2005) pointed the