A method for assessing generalised nitrogen leaching estimates for agricultural land |
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Authors: | M Hoffmann H Johnsson |
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Institution: | (1) Department of Soil Sciences, Division of Water Quality Management, Swedish University of Agricultural Sciences, P.O. Box 7072, S-750 07 Uppsala, Sweden |
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Abstract: | The purpose of this study was to develop a method for assessing generalised N leaching estimates from large areas of agricultural
land. The system developed was based on calculating a number of N leaching estimates for different typical cropping situations.
The estimates were normalised with respect to varying weather conditions and crop production. The different cropping situations
were described by setting up a matrix consisting of crucial factors influencing leaching such as soils, crops and climate.
Nitrogen leaching was then estimated for a number of combinations of these factors. Calculations were made for three different
regions where all the major crops were cultivated on soils with seven different textures and four different organic-N classes
and two fertilisation regimes. The three regions are representative of climates and agricultural practices in some of the
major agricultural areas in Sweden. The model used was the SOILN model.
Leaching of nitrogen from the root zone showed large variations. The range was from 1 to 50 kg ha−1 for different soils and crops when only fertiliser N was applied. Leaching varied both due to different climates and differences
in cultivation practices between the regions. Leaching decreased in a south-north gradient. Leaching increased as a result
of greater mineralisation when the organic matter content in the soils was increased, leaching was less from soils with a
high clay content and was very small for the heavy clay soil.
This revised version was published online in July 2006 with corrections to the Cover Date. |
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Keywords: | modeling soils crops water quality impact simulation |
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