Compilation of minimum and maximum isotope ratios of selected elements in naturally occurring terrestrial materials and reagents

Coplen, T.B.; Hopple, Jessica A.; Böhlke, John K.; Peiser, H. S.; Rieder, S. E.; Krouse, H. R.; Rosman, K.J.R.; Ding, Tzung‐Su; Vocke, Robert D.; Révész, Kinga; Lamberty, A.; Taylor, Philip; Bièvre, Paul De

doi:10.3133/wri014222

Cited by 16 publications

(1 citation statement)

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“…If the legumes fix N 2 from the atmosphere via their symbiotic rhizobia, the δ 15 N value of soil and plants is shifted towards 0‰ (Evans, 2001;Inglett et al, 2004). Because mineral fertilizers frequently show negative δ 15 N values, mineral fertilization can also decrease the δ 15 N values of soils and plants (Choi et al, 2017;Coplen et al, 2002;Park et al, 2015). As a consequence, in legume-containing and fertilized ecosystems δ 15 N values could decrease even if the N cycling does not become tighter.…”

Section: Introductionmentioning

confidence: 99%

Does biochar contribute to close nutrient cycles of tree plantations on degraded Ultisols in the Ecuadorian Amazonia?

Sarango

Manosalvas

Wilcke

2022

Soil Use and Management

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The use of biochar is expected to improve soil fertility and close nutrient cycles in degraded strongly weathered tropical soils. We, therefore, hypothesized that biochar amendment to tree plantations (a) increases nutrient fluxes with litterfall alone and with mineral fertilizer plus lime and (b) reduces N losses reflected by lower δ 15 N values of litterfall and soils than in unamended controls. We grew the native leguminous Schizolobium parahyba var. amazonicum (Ducke) Barneby and the exotic Gmelina arborea Roxb at two sites. We used a replicated full factorial split-split plot design of amendment of mineral fertilizer plus lime, 3 and 6 t ha −1 biochar, and a control. We collected litterfall biweekly (2012)(2013) and topsoil samples (0-0.25 m) in 2009 before tree planting, in 2011 and 2013. Fertilizer plus lime increased the mean annual concentrations of P, Ca and Zn in litterfall but decreased that of Mn. At the same time, fertilizer plus lime increased the annual fluxes of nutrients, Na and Al with litterfall. During the dry season, biochar decreased the N concentration in litterfall and the K flux with litterfall. During the rainy season, biochar increased the concentrations of Ca and Zn in litterfall and their fluxes with litterfall. Biochar did not influence the δ 15 N values of soil and litterfall after 51 months of tree growth. Fertilizer plus lime decreased the δ 15 N values of soil, because of the lower δ 15 N value of the used urea (−0.30‰) than the soil (4.5‰-7.8‰). Moreover, fertilizer plus lime increased the δ 15 N values of litterfall, possibly because of enhanced 14 N leaching from the N-rich canopies. The amendment of up to 6 t ha −1 biochar did not contribute to close nutrient cycles.

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