[Lysimeter trial 1981-1996: nitrogen leaching under crop rotation]
1997
Nievergelt, J. (Eidg. Forschungsanstalt fuer Agraroekologie und Landbau (FAL), Reckenholz (Switzerland))
Under the conditions of the lysimeter experiment at Zurich-Reckenholz (Switzerland) - 1000 mm annual precipitation (400 mm from October to March), mineral fertilisation, green manure before potato, corn and sugar beet - crop type and position of the crop in the rotation were the most crucial factors for nitrate leaching. Maximum risk was evaluated for potato followed by winter wheat; medium risk for spring wheat and corn; and the lowest risk for temporary meadow and sugar beet. In any year there was enough leaching water in order that nitrate could leach below the root zone, especially outside the main growing season (April to September). Therefore, the influence of the amount of precipitation in a given year was small. Differences in yield and nitrogen leaching between two soil types, one well-drained stony cambisol (FAO) developed from a stony alluvium (Schotter), the other a poorly-drained fine-textured cambisol developed from moraine deposits (Moraene) can be summarised as follows: on Schotter yield was 24 % lower and nitrogen leaching 17 % higher than on Moraene
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