Action reducing the outflow of nitrates from agricultural sources to waters on the nitrate vulnerable zone in the catchment of the Samica Stęszewska river

Abstract

Action reducing the outfl ow of nitrates from agricultural sources to waters on the nitrate vulnerable zones in the catchment of the Samica Steszewska river. The aim of the performed investigations was to assess the scope and effectiveness of actions undertaken on the Nitrate Vulnerable Zone (NVZ) in a catchment area with waters sensitive to agricultural pollution. The investigations on the catchment of the Samica Steszewska river were conducted in 2005–2007. They included, among others: the estimation of the quality of surface waters, directions and the intensity of agricultural activity, applied agricultural practices, plans and balances of fertilization. The investigations showed that arable lands predominate the examined catchment area of the Samica Steszewska river and agricultural activity contributed signifi cantly to water pollution. Many farms lacked buildings and the devices for proper storage of manures. The majority of farms realize intensive agricultural production, many of them specialise in swine breeding. High fertilization is complied on farms often and high livestock density. It is the reason of introducing the large quantities of nutrients to agro-ecosystems and causes the nutrient surpluses in balance. Farmers were well-acquainted with principles of good agricultural practice and declared the will of realization of actions introduced on vulnerable zones aiming at reducing nitrates from agricultural sources. The majority of farmers complied with recommendations of the Code of Good Agricultural Practice. No farm exceeded the quantity of 170 kg N·ha–1 in manures recommended in the Nitrates Directive, yet the level of fertilization on the catchment area was high.