Department of Technical Biogeochemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstr. 15, 04318 Leipzig, Germany; Department of Environmental Sciences, Forman Christian College (A Chartered University), Ferozepur Road, 54600 Lahore, Pakistan.
Department of Technical Biogeochemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstr. 15, 04318 Leipzig, Germany.
Sci Total Environ. 2024 Mar 25;918:170643. doi: 10.1016/j.scitotenv.2024.170643. Epub 2024 Feb 5.
Glyphosate and nitrogen (N) or (P) phosphorus fertilizers are often applied in combination to agricultural fields. The additional P or N supply to microorganisms might drive glyphosate degradation towards sarcosine/glycine or aminomethylphosphonic acid (AMPA), and consequently determine the speciation of non-extractable residues (NERs): harmless biogenic NERs (bioNERs) or potentially hazardous xenobiotic NERs (xenoNERs). We therefore investigated the effect of P or N-fertilizers on microbial degradation of glyphosate and bioNER formation in an agricultural soil. Four different treatments were incubated at 20 °C for 75 days as follows; I: no fertilizer (2-C,N-glyphosate only, control), II: P-fertilizer (superphosphate + 2-C,N-glyphosate, effect of P-supply), III: N-fertilizer (ammonium nitrate + 2-C,N-glyphosate, effect of N-supply) and IV: N-fertilizer (N-ammonium nitrate + 2-C-glyphosate, differentiation between microbial assimilations of N: N-fertilizer versus N-glyphosate). We quantified C or N in mineralization, extractable residues, NERs and in amino acids (AAs). At the end, mineralization (36-41 % of the C), extractable 2-C,N-glyphosate/2-C-glyphosate (0.42-0.49 %) & N-AMPA (1.2 %), and C/N-NERs (40-43 % of the C, 40-50 % of the N) were comparable among treatments. Contrastingly, the N-NERs from N-fertlizer amounted to only 6.6 % of the N. Notably, N-fertilizer promoted an incorporation of C/N from 2-C,N-glyphosate into AAs and thus the formation of C/N-bioNERs. The C/N-AAs were as follows: 16-21 % (N-fertilizer) > 11-13 % (control) > 7.2-7.3 % (P-fertilizer) of the initially added isotope. 2-C,N-glyphosate was degraded via the sarcosine/glycine and AMPA simultaneously in all treatments, regardless of the treatment type. The percentage share of bioNERs within the NERs in the N-fertilized soil was highest (C: 80-82 %, N: 100 %) compared to 53 % (C & N, control) and to only 30 % (C & N, P-fertilizer). We thus concluded simultaneous N & glyphosate addition to soils could be beneficial for the environment due to the enhanced bioNER formation, while P & glyphosate application disadvantageous since it promoted xenoNER formation.
草甘膦和氮（N）或（P）磷肥料通常同时施用于农业领域。微生物的额外 P 或 N 供应可能会促使草甘膦降解为肌氨酸/甘氨酸或氨甲基膦酸（AMPA），并因此决定不可提取残留物（NER）的形态：无害的生物源性 NER（bioNER）或潜在的有害异生物质源性 NER（xenoNER）。因此，我们研究了 P 或 N 肥料对农业土壤中草甘膦微生物降解和 bioNER 形成的影响。四种不同的处理在 20°C 下孵育 75 天，如下所示：I：无肥料（仅 2-C，N-草甘膦，对照），II：P 肥料（过磷酸钙+2-C，N-草甘膦，P 供应的影响），III：N 肥料（硝酸铵+2-C，N-草甘膦，N 供应的影响）和 IV：N 肥料（N-硝酸铵+2-C-草甘膦，区分微生物对 N 的同化：N 肥料与 N-草甘膦）。我们量化了矿化、可提取残留物、NER 和氨基酸（AA）中的 C 或 N。最后，矿化（C 的 36-41%）、可提取的 2-C，N-草甘膦/2-C-草甘膦（0.42-0.49%）和 N-AMPA（1.2%）以及 C/N-NER（C 的 40-43%，N 的 40-50%）在处理之间相当。相比之下，N 肥料中的 N-NER 仅占 N 的 6.6%。值得注意的是，N 肥料促进了从 2-C，N-草甘膦到 AA 的 C/N 掺入，从而形成了 C/N-bioNER。C/N-AA 如下：16-21%（N 肥料）>11-13%（对照）>7.2-7.3%（P 肥料）初始添加的同位素。2-C，N-草甘膦在所有处理中均通过肌氨酸/甘氨酸和 AMPA 同时降解，无论处理类型如何。与 53%（C 和 N，对照）相比，在 N 施肥土壤中 bioNER 在 NER 中的百分比份额最高（C：80-82%，N：100%），而仅为 30%（C 和 N，P 施肥）。因此，我们得出结论，由于增强的 bioNER 形成，同时向土壤中添加 N 和草甘膦可能对环境有益，而 P 和草甘膦的应用则不利，因为它促进了异生物质源性 NER 的形成。
