Irrigation management, nitrogen fertilization and nitrogen losses in the return flows of La Violada irrigation district (Spain)

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• 作者：R. Barros ; D. Isidoro ; ^{disidoro@aragon.es} ; R. Aragü ; é ; s
• 关键词：Nitrogen use efficiency ; Non-point pollution ; Fertilization ; Nitrate ; Nitrogen balance ; Irrigation efficiency ; La Violada irrigation district
• 刊名：Agriculture ; Ecosystems & Environment
• 出版年：2012
• 期刊代码：6_01678809
• 类别：abs
• 出版时间：15 July, 2012
• 卷：155
• 期：Complete
• 页码：161-171
• 文件大小：1099 K

摘要

Nitrogen (N) pollution induced by irrigated agriculture is a significant environmental problem. The main N inputs and outputs were measured or estimated in the semi-arid La Violada irrigation district (Spain). Data on two periods (1995-1998 and 2006-2008) were compared and related to observed changes during the decade in cropping patterns and N fertilization and irrigation management. N fertilization exceeded crop N uptake due to over-fertilization of corn (426 kg N/ha in 1995-1998 and 332 kg N/ha in 2006-2008) and alfalfa (62 kg N/ha). Between the two periods, N fertilization decreased by 56%, primarily due to a change from corn to alfalfa and barley. Accordingly, N losses in the irrigation return flows (IRF) diminished from 31%of the applied fertilizer in 1995-1998 to 20%in 2006-2008. NO₃^{鈭?/sup> concentrations and NO₃-N loads in the IRF decreased from 40 mg/L and 106 kg N/ha in 1995-1998 to 21 mg/L and 22 kg N/ha in 2006-2008, due to lower N fertilization, lower corn area and improved irrigation efficiency. N contamination in the IRF will be minimized by increasing the irrigation efficiency and decreasing the corn area and its N fertilization rates, particularly when supplemental organic N is applied at pre-sowing.}