Quantification of symbiotic nitrogen fixation by Elaeagnus angustifolia L. on salt-affected irrigated croplands using two ¹⁵N isotopic methods

• Published in: Nutrient cycling in agroecosystems 2010-12, Vol.88 (3), p.329-339
• Main Authors: Djumaeva, D, Lamers, J. P. A, Martius, C, Khamzina, A, Ibragimov, N, Vlek, P. L. G
• Format: Article
• Language: English
• Subjects: Afforestation; Agricultural land; agricultural soils; Agriculture; Ammonium; Ammonium nitrate; Biomedical and Life Sciences; ecological restoration; Elaeagnus angustifolia; Environmental restoration; Gleditsia triacanthos; irrigated soils; Life Sciences; Lysimeters; Nitrates; nitrogen; nitrogen fertilizers; Nitrogen fixation; Nitrogen isotopes; Nitrogenation; Original Article; Plant growth; plant nutrition; Restoration; Saline soils; stable isotopes; symbiosis; tree age; Trees; Ulmus pumila
• ISSN: 1385-1314; 1573-0867
• DOI: 10.1007/s10705-010-9357-5

Afforestation with fast growing N-fixing trees is an option for ecological restoration of highly-salinized irrigated croplands, but information about the N-fixing capability of trees on saline soils is sparse. The ¹⁵N-enrichment technique (¹⁵NET) and the A value (AV) method were used to quantify in lysimeters the proportion of atmospheric N₂ (%Ndfa) fixed by Elaeagnus angustifolia L., with a reference to non-N-fixing Gleditsia triacanthos L. and Ulmus pumila L. Twenty kg N ha⁻¹ of 5 atom %¹⁵N excess ammonium nitrate (35% N) was applied to 1-year-old trees in 2007 and 2-year-olds in 2008. Since this rate was insufficient for the older reference trees, 60 kg N ha⁻¹ was applied in 2008. With ¹⁵NET, the %Ndfa of E. angustifolia in 2007 was 79% when referenced against U. pumila and 68% against G. triacanthos. With the AV method, the %Ndfa of 2-year-old E. angustifolia was 80 and 68% when referenced against U. pumila and G. triacanthos, respectively. Over 2 years, E. angustifolia fixed 17 kg N ha⁻¹ when related to U. pumila and 14 kg N ha⁻¹ with G. triacanthos (assumed density: 5,000 trees ha⁻¹). N-fixing E. angustifolia has the potential to be self-sufficient in N when planted in the strongly saline soils.