Native plants and nitrogen in agricultural landscapes of New Zealand
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Background and Aims: The Canterbury Plains of the South Island, New Zealand are being converted to intensive dairy farming; native vegetation now occupies < 0.5 % of the area. Reintroducing native species into nutrient-rich systems could provide economic, environmental and ecological benefits. However, native species are adapted to low nitrogen (N) environments. We aimed to determine the growth and N-uptake response of selected native species to elevated soil N loadings and elucidate the effect of these plants on the N speciation in soil. Methods: Plant growth, N-uptake, and N speciation in rhizosphere soil of selected native species and Lolium perenne (ryegrass, as reference) were measured in greenhouse and field trials. Results: At restoration sites, several native species had similar foliar N concentrations to ryegrass. Deciduous (and N-fixing) species had highest concentrations. There was significant inter-species variation in soil mineral N concentrations in native plant rhizospheres, differing substantially to the ryegrass root-zone. Pot trials revealed that native species tolerated high N-loadings, although there was a negligible growth response. Among the native plants, monocot species assimilated most N. However, total N assimilation by ryegrass would exceed native species at field productivity rates. Conclusions: Selected native plant species could contribute to the sustainable management of N in intensive agricultural landscapes.
Plant and Soil
Copyright 2017 Springer Netherlands. This is an electronic version of an article published in Plant and Soil, Volume 394, Issue 1–2, pp 407–420, 2015. Plant and Soil is available online at: http://link.springer.com/ with the open URL of your article.