The effect of grassland renovation on soil mineral nitrogen and on nitrate leaching during winter |
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Authors: | Kirsten Seidel Manfred Kayser Jürgen Müller Johannes Isselstein |
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Institution: | 1. Research Centre for Animal Production and Technology, University of G?ttingen, Driverstra?e 22, 49377 Vechta, Germany;2. Present address: Institute for Land Use, University of Rostock, Justus‐von‐Liebig‐Weg 6, 18059 Rostock, Germany;3. Department of Crop Sciences, Grassland Science, University of G?ttingen, von‐Siebold‐Stra?e 8, 37075 G?ttingen, Germany |
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Abstract: | Renovation of grassland may increase the mineralization of organic material and leads to a high amount of mineral N in soil which can be leached in the winter period. Soil mineral N (SMN) in autumn and calculated nitrate leaching during winter were measured after the renewal of 8 y–old cut grassland on a sandy soil in NW Germany in 1999 to 2002. Several factors, which may influence the intensity of N mineralization, were investigated in the 2 years following renewal: the season of renovation (spring or late summer/early autumn), the technique (rotary cultivator or direct drilling), and the amount of N fertilization (0 or 320 kg N ha–1 y–1 in the 7 years before the renovation). Calculated nitrate‐N leaching losses during winter were significantly higher following renewal in early autumn (36–64 kg N ha–1) compared to renewal in spring (1–7 kg N ha–1). This effect was only significant in the first, not in the second winter after renovation. The renovation technique had a significant effect on the nitrate‐N leaching losses only in the first year after the renovation. Direct drilling led to higher leaching losses (35 kg N ha–1) than the use of a rotary cultivator (30 kg N ha–1) in the same year. Calculated nitrate losses (on average over 60 kg N ha–1) were highest after renewal of N‐fertilized grassland in late summer/early autumn. To minimize N leaching losses, it would be more effective to plan grassland renewal in spring rather than in late summer/autumn. Another, however, less effective option is to reduce N fertilization before a renovation in autumn. |
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Keywords: | grassland nitrate leaching renewal renovation |
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