Rasmussen, Jim
- Department of Soil and Environment, Swedish University of Agricultural Sciences
The N flow dynamics in grass clover mixtures are not well understood. Spatial distributions and temporal differences in inter- and intra-species N transfer were investigated at field sites in Iceland, Germany, and Denmark, with three different managements at the Danish site. Both grass and white clover were leaf-labeled four times during a full year and the short-term N transfer to neighboring grass and white clover was determined in 10 cm intervals up to 1 m from the labeled plant. In addition N-15-injection of inorganic N at 5, 15, and 25 cm soil depth was carried out at the Danish site to compare spatial and temporal N transfer patterns to soil inorganic N uptake. The short-term N transfer from white clover to the closest companion grass reached levels of more than 50% of N from labeled white clover late in the growing season, thus questioning whether longer-term root turnover processes are dominating N transfer. The horizontal N transfer to grass exceeded 50 cm from the labeled plant at one site. The study showed that the competitive ability of white clover is as important for N dynamics in grass white clover mixtures as that of the companion grass. Intra-species N transfer showed that both grass and white clover have reuptake of deposited N corresponding to at least 1% of the N found in leaf biomass. The study also showed that N transfer cannot be explained simply by competition for soil inorganic N, which indicates transfer via organic N forms. (C) 2012 Elsevier Ltd. All rights reserved.
Intra-species N transfer; Inter-species N transfer; Organic N uptake; N reuptake; Soil N uptake
Soil Biology and Biochemistry
2013, volume: 57, pages: 654-662
Publisher: PERGAMON-ELSEVIER SCIENCE LTD
Agricultural Science
https://res.slu.se/id/publ/53893