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Simulating nitrate retention in soils and the effect of catch crop use and rooting pattern under the climatic conditions of Northern Europe
Author(s) -
Pedersen A.,
ThorupKristensen K.,
Jensen L. S.
Publication year - 2009
Publication title -
soil use and management
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.709
H-Index - 81
eISSN - 1475-2743
pISSN - 0266-0032
DOI - 10.1111/j.1475-2743.2009.00220.x
Subject(s) - loam , soil water , agronomy , leaching (pedology) , environmental science , crop , soil horizon , nitrate , soil texture , brassica , precipitation , soil science , biology , geography , ecology , meteorology
This model analysis of catch crop effects on nitrate retention covered three soil texture classes (sand, loamy sand, sandy loam) and three precipitation regimes in a temperate climate representative of northern Europe (annual precipitation 709–1026 mm) for a period of 43 years. Simulations were made with two catch crops (ryegrass and Brassica ) with different rooting depths, and soil N effects in the next spring were analysed to 0.25, 0.75 and 2.0 m depth to represent the catch crop effect on following crops with different rooting depths. Nitrate retained without a catch crop was generally located in deeper soil layers. In the low precipitation regime the overall fraction of nitrate retained in the 0–2.0 m soil profile was 0.23 for the sandy soil, 0.69 for the loamy sand and 0.81 for the sandy loam. Ryegrass reduced leaching losses much less efficiently than Brassica , which depleted nitrate in the 0–0.75 m soil layer more completely, but also in the deeper soil layer, which the ryegrass could not reach. A positive N effect (N eff , spring mineral N availability after catch crop compared with bare soil) was found in the 0–0.25 m layer (that is shallow rooting depth of a subsequent main crop) in all three soil texture classes, with on average 10 kg N/ha for ryegrass and 34 kg N/ha for Brassica . Considering the whole soil profile (0–2.0 m deep rooting of next crop), a positive N eff was found in the sand whereas generally a negative N eff was found in the loamy sand and especially the sandy loam. The simulations showed that for shallow‐rooted crops, catch crop N eff values were always positive, whereas N eff for deeper‐rooted crops depended strongly on soil type and annual variations in precipitations. These results are crucial both for farmers crop rotation planning and for design of appropriate catch crop strategies with the aim of protecting the aquatic environment.