Changes in irrigation management and quantity and quality of drainage water in a traditional irrigated land

摘要: Irrigated agriculture allows for the increase of agrarian yields and stability in food supply raw materials, being, at same time, responsible reduction water resources availability pollution by salts nitrate. This work aims to analyze impact changes irrigation management (establishment an on-demand flood irrigated system, assignment allowances payment surface consumption) a traditional land on drainage flow, electrical conductivity nitrate concentration return flows between year 2001 period 2005–2008. Changes significantly modified quantity (lower drainage) quality (electrical nitrate) flows, keeping similar evolution paths during with ameliorants summer due use good quality. Salinity is not current problem area as values did exceed limit established used or intended human consumption. Despite fact that crop distribution have reduced concentrations 43 %, still presents exceeding 50 mg NO3 −/l. Thus, remains main agro-environmental this area. However, trends detected mark possibility reaching below −/l case maintenance conditions agricultural system.