期刊名称：Science et changements planétaires / Sécheresse
印刷版ISSN：1147-7806
电子版ISSN：1777-5922
出版年度：1995
卷号：6
期号：2
页码：189-200
出版社：John Libbey Eurotext
摘要：Authors Anne-Marie de Cockborne , Laurent Bruckler , Gérard Auge Inra-Unité de Science du sol, Domaine St Paul, Site Agroparc, 84914 Avignon cedex 9, France, Chambre d’Agriculture du Gard, 7, rue B. Aton, 30000 Nîmes, France Page(s) : 189-200 Published in: 1995 The aim of the present study was to test the ability of the water and nitrate balance methods to assess nitrate pollution and produce consistent estimates at the field or regional level when data of varying quality are used. For field analysis, the data came from an intensive market garden plot (1992 to 1993), and for regional analysis, from an agricultural network in the Mediterranean zone (Gard, Vistrenque water table), where market gardening is well developed. Quantitative estimates of water and nitrate flow can only be obtained if the main terms in the calculations are well known. For example: irrigation water may contain large quantifies of nitrate, and actual evapotranspiration may vary considerably - rough estimates of either can obviously lead to wrong conclusions. Other sources of error include bias in drainage estimates due to neglecting monthly variations in water storage, the variability in the spatial distribution of irrigation or in the nitrogen cycle. In calculations of soil nitrate concentrations, the maximum period should be the month. Our results for the Mediterranean zone showed soil nitrate levels to diminish during spring and autumn. This was ascribed to excess water in a soil of poor or non-existent plant cover: too much irrigation in the spring, and rain in the autumn. In this region, improved control over the quantifies of nitrogen reaching the underground water will probably require better management of irrigation both in-season (spring and summer) and between crops (autumn and winter).
