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Nitrogen fertilization and nitrate leaching into groundwater on arable sandy soils
Author(s) -
Köhler Kai,
Duynisveld Wilhelmus H. M.,
Böttcher Jürgen
Publication year - 2006
Publication title -
journal of plant nutrition and soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.644
H-Index - 87
eISSN - 1522-2624
pISSN - 1436-8730
DOI - 10.1002/jpln.200521765
Subject(s) - leaching (pedology) , soil water , arable land , fertilizer , groundwater recharge , groundwater , environmental science , nitrate , lessivage , soil science , agronomy , nitrogen , chemistry , hydrology (agriculture) , ecology , geology , aquifer , agriculture , biology , geotechnical engineering , organic chemistry
Nitrate leaching depending on N fertilization and different crop rotations was studied at two sites with sandy soils in N Germany between 1995 and 2000. The leaching of NO $ _3^- $ was calculated by using a numerical soil‐water and N model and regularly measured N min values as input data. Also the variability of N min values on the sandy soils was determined along transects. They reveal the high variability of the N min values and show that it is not possible to confirm a significant N min difference between fertilizer treatments using the normal N min ‐sampling intensity. Nitrate‐leaching calculations of five leaching periods showed that even strongly reduced N‐fertilizer applications did not result in a substantially lower NO $ _3^- $ leaching into the groundwater. Strong yield reductions of even more than 50%, however, were immediately measured. Mean NO $ _3^- $ concentrations in the groundwater recharge are >50 mg L –1 and are mainly due to mineralization from soil organic matter. Obviously, the adjustment of the N cycle in the soil to a new equilibrium and a reduced NO $ _3^- $ ‐leaching rate as a consequence of lower N inputs need a much longer time span. Catch crops are the most efficient way to reduce the NO $ _3^- $ concentrations in the groundwater recharge of sandy soils. Their success, however, strongly depends on the site‐specific development possibilities of the catch crop. Even with all possible measures implemented, it will be almost impossible to reach NO $ _3^- $ concentrations <50 mg L –1 in sandy soils. The only way to realize this goal on a regional scale could be by increasing areas with lower nitrate concentrations in the groundwater recharge like grassland and forests.