Resumen
The poor condition of surface water is still a problem in many countries, including Lithuania. To assess the impact of organic agricultural production on groundwater and surface water quality in Lithuania, surface water samples from rivers and other bodies of water are usually studied, leaving the properties of groundwater in agricultural fields unknown. Samples of river water and groundwater collected from both organic and intensive farming fields bordering the studied rivers were investigated in this study. The study was conducted on five rivers located in the Nemunas River Basin District and in 23 cultivated neighboring fields, where wells were drilled 4?5 m deep for groundwater sampling. All five rivers corresponded to the values of good and very good in terms of their ecological status, according to the values of PO4-P and NH4-N. According to the total P value, one river did not correspond to the values of good or very good ecological status. According to the total N value, four rivers did not meet the values of good or very good ecological status. We found that, with the exception of one farm, the pH, total P, total N, and NO3-N, as well as the concentrations of NH4-N and PO4-P, in the groundwater from organic farms were lower compared to the groundwater from intensive farming areas. This suggests the importance of ground water sampling in addition to surface water surveys in water quality studies related to agricultural production.