ABSTRACT
Water quality is one of the fundamental requisites for sustainable development of agriculture, and it constitutes the survival determinant of rich plant and animal assemblages. Activities aiming at water pollution control in the 1970s and up to the mid-1980s focused on treating urban and industrial sewage effluents — that is, on the control of point sources of pollution by construction of water purification plants. Consolidation and expansion of cultivated fields led to eradication of field margins, hedges, shelterbelts, small mid-field ponds or wetlands, and other nonproductive elements of the landscape. Meadows and pastures located in depressions close to channels, ponds, and lakes and among cultivated fields cover 12% of the area. The small area under planted shelterbelts or grass strips shows unproportionally high control effects compared with those gained when it is extended to a larger size. Meadows, shelterbelts, and small forests represented the perennial vegetation.
