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本文研究了挪威东南部三个小型农业流域(10～40hm~2)1992～1995早期间的土壤无机氮和氮流失情况。在本研究中特别关注了土壤和农作物管理,以及天气条件的时间变异性。流域尺度上的氮流失与流域面积内的土壤无机氮含量相关性很好。氮损失与农作物产量成负相关。因而,农作物的减产导致了其后秋季和冬季氮流失的大量增加。农作物产量以及与土壤有机质含量和管理有关的因素能够解释土壤中无机氮的大部分变异。由于有机质的转化主要是一个生物过程,因此天气条件对氮的矿化有重要作用。天气条件也影响流域尺度上的氮流失。本研究表明,淋溶的氮主要来源于有机质的矿化,而不是施用的肥料。因此,农作物系统、农作物管理和土壤有机质管理是影响农田中氮损失的关键因素。
In this paper, the loss of soil inorganic nitrogen and nitrogen in three small-scale agricultural basins (10 ~ 40hm ~ 2) in southeast Norway from 1992 to 1995 was studied. In this study, special attention was given to soil and crop management, as well as the temporal variability of weather conditions. There is a good correlation between the scale of nitrogen loss in the catchments and the content of inorganic nitrogen in the catchment area. Nitrogen loss is negatively correlated with crop yield. Consequently, crop yields have led to a substantial increase in subsequent nitrogen losses in autumn and winter. Crop yield and factors related to soil organic matter content and management explain most of the variation in inorganic nitrogen in the soil. Since the conversion of organic matter is mainly a biological process, the weather conditions play an important role in the mineralization of nitrogen. Weather conditions also affect the scale of nitrogen loss on the basin. This study shows that leached nitrogen is mainly derived from the mineralization of organic matter, not the applied fertilizer. Therefore, crop systems, crop management and management of soil organic matter are key factors affecting nitrogen loss in farmland.