Bradbury Ember Sienna, Holland-Moritz Hannah, Gill Amy, Havrilla Caroline A
Department of Forestry and Rangeland Stewardship, Colorado State University, Fort Collins, CO, United States.
Department of Natural Resources and the Environment, University of New Hampshire, Durham, NC, United States.
Front Microbiol. 2024 Dec 18;15:1450633. doi: 10.3389/fmicb.2024.1450633. eCollection 2024.
Land stewards in dryland ecosystems across the western U.S. face challenges to manage the exotic grass (cheatgrass), which is a poor forage, is difficult to remove, and increases risk of catastrophic fire. Managers may consider using indaziflam (Rejuvra™), a relatively new pre-emergent herbicide, which may reduce cheatgrass cover within drylands. However, few studies have explored the effects of indaziflam on non-target organisms. We tested how indaziflam application impacted cover and biomass of native and exotics within the plant community and composition and diversity of the soil microbiome by comparing untreated and treated arid shrubland sites in Boulder County, Colorado, USA. We found that indaziflam application decreased cheatgrass cover by as much as 80% and increased native plant cover by the same amount. Indaziflam application also was associated with increased soil nitrate (NO ), decreased soil organic matter, and had a significant effect on the composition of the soil microbiome. Microbial community composition was significantly related to soil NO , soil organic matter, soil pH, and native species and cheatgrass biomass. An indicator species analysis suggested that indaziflam application shifted microbial communities. In untreated sites, ammonia-oxidizing bacteria and nitrogen-digesting and the fungi were found. While in treated sites, ammonia-oxidizing archaea which are associated with intact drylands, and toxin digesters and acidic-soil species and were significantly associated. Overall, these results demonstrate that indaziflam application can increase native plant recruitment, while also affecting soil properties and the soil microbiome. The findings from this study can be used to inform decision-making during dryland restoration planning process as indaziflam use may have benefits and unknown long-term consequences for the biogeochemistry and microbial ecology of the system.
美国西部旱地生态系统的土地管理者在管理外来杂草（黑麦草）上面临挑战，这种杂草是劣质草料，难以清除，还会增加灾难性火灾的风险。管理者可能会考虑使用吲唑磺草胺（Rejuvra™），一种相对较新的芽前除草剂，它可能会减少旱地内黑麦草的覆盖面积。然而，很少有研究探讨吲唑磺草胺对非目标生物的影响。我们通过比较美国科罗拉多州博尔德县未处理和处理过的干旱灌木丛场地，测试了吲唑磺草胺的施用如何影响植物群落中本地植物和外来植物的覆盖度与生物量，以及土壤微生物群落的组成和多样性。我们发现，施用吲唑磺草胺可使黑麦草覆盖度降低多达80%，同时使本地植物覆盖度增加相同幅度。施用吲唑磺草胺还与土壤硝酸盐（NO）增加、土壤有机质减少有关，并且对土壤微生物群落的组成有显著影响。微生物群落组成与土壤NO、土壤有机质、土壤pH值以及本地物种和黑麦草生物量显著相关。指示物种分析表明，施用吲唑磺草胺改变了微生物群落。在未处理的场地中，发现了氨氧化细菌、氮消化菌和真菌。而在处理过的场地中，与完整旱地相关的氨氧化古菌、毒素分解菌和酸性土壤物种显著相关。总体而言，这些结果表明，施用吲唑磺草胺可以增加本地植物的补充，同时也会影响土壤性质和土壤微生物群落。这项研究的结果可用于为旱地恢复规划过程中的决策提供信息，因为吲唑磺草胺的使用可能对该系统的生物地球化学和微生物生态学有好处，但也有未知的长期后果。
