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While improved management of agricultural landscapes is promoted as a promising natural climate solution, available estimates of the mitigation potential are based on coarse assessments of both agricultural extent and aboveground carbon density. Here we combine 30 meter resolution global maps of aboveground woody carbon, tree cover, and cropland extent, as well as a 1 km resolution map of global pasture land, to estimate the current and potential carbon storage of trees in nonforested portions of agricultural lands. We find that global croplands currently store 3.07 Pg of carbon (C) in aboveground woody biomass (i.e., trees) and pasture lands account for an additional 3.86 Pg C across a combined 3.76 billion ha. We then estimate the climate mitigation potential of multiple scenarios of integration and avoided loss of trees in crop and pasture lands based on region‐specific biomass distributions. We evaluate our findings in the context of nationally determined contributions and find that the majority of potential carbon storage from integration and avoided loss of trees in crop and pasture lands is in countries that do not identify agroforestry as a climate mitigation technique.

Quantifying the fate of organic nitrogen in aquatic systems is important to improve understanding of its recycling efficiency and long‐term preservation. The fate of organic nitrogen can be investigated with¹⁵N labeling techniques, but relative amounts of¹⁵N in different chemical forms are difficult to quantify. We present a “streamlined” method by combining Ammonium Retention Time Shift‐High Performance Liquid Chromatography with zinc reduction, and UV oxidation. This method does not require a pre‐isolation step of different forms of nitrogen from the sample. At a sample volume of 50 mL, and a total N concentration in the range of 0.5–40 μmol N L⁻¹, and an¹⁵N atom% of 20–80%,¹⁵N concentrations for all N forms can be measured with this streamlined method, with a precision of within ±7%, and an accuracy of over 97%. We applied the method to investigating the short‐term fates of¹⁵N during the degradation of¹⁵N‐labeled amino acid and peptide. Recovery rates ranged from 93% to 110%, with an average of 102 ± 1.94%. As spiked¹⁵N labeled alanine and/or peptide (Ala‐Val‐Phe‐Val) disappeared during sample incubations, a large fraction (ca. 13–66%) of the¹⁵N was progressively transformed to non‐amino acid or non‐peptide dissolved organic nitrogen. This streamlined method offers quantitative estimates of potential fates of labile organic N compounds added to water samples containing in situ microbial consortia, and helps fulfill knowledge gaps in building the budget of N transformations of labile amino acids and peptides in aquatic systems.