Ezekiel K. Bore , Pauliina Turunen , Outi-Maaria Sietiö , Lukas Kohl , Markku I.K. Koskinen , Jussi Heinonsalo , Kristiina L. Karhu , Mari K. Pihlatie
{"title":"Plant phenology modulates and undersown cover crops mitigate N2O emissions","authors":"Ezekiel K. Bore , Pauliina Turunen , Outi-Maaria Sietiö , Lukas Kohl , Markku I.K. Koskinen , Jussi Heinonsalo , Kristiina L. Karhu , Mari K. Pihlatie","doi":"10.1016/j.soilbio.2024.109548","DOIUrl":null,"url":null,"abstract":"<div><p>Mitigation of N<sub>2</sub>O emissions, a potent greenhouse gas, remain challenging due to knowledge gaps in plant-mediated nitrogen (N) transformation pathways, which limits ability to identify optimal approaches for efficient N utilization. We set up mesocosms with barley, Italian ryegrass, and barley in combination with Italian ryegrass to assess role of cover crop in N<sub>2</sub>O emission mitigation. Soil emitted N<sub>2</sub>O was collected simultaneously from the pots with plants at three growth stages: namely, vegetative, canopy expansion, and grain filling. The gas sample N<sub>2</sub>O contents, N in microbial biomass (MBN), mineral N content, and phospholipid fatty acid (PLFA) analysis in soils were determined at the three growth stages. Cumulatively, highest N<sub>2</sub>O was emitted from soil under Italian ryegrass (0.056 mg N g<sup>−1</sup> soil) followed by barley (0.0051 mg N g<sup>−1</sup> soil) and the least under barley and Italian ryegrass combination (0.0014 mg N g<sup>−1</sup> soil). The high emissions under Italian ryegrass occurred at vegetative stage due to high reactive N availability. Strong emissions were observed at canopy expansion stage under barley and were linked to access to the large mineral N proportion redistributed to the lower depth as depicted by highest MBN (0.025 mg N g<sup>−1</sup> soil) and decreased extractable N (0.0068 mg N g<sup>−1</sup> soil). The high emissions under barley correlated with high fungal/bacterial ratio, pointing towards a fungal role in the emissions. The least soil N<sub>2</sub>O emissions under barley and Italian ryegrass combination were accompanied by elimination of variations induced by the plant growth stages. Absence of <em>18:2ω6,9</em> fungal PLFA biomarker under barley and Italian ryegrass combination indicates a potential inhibition and corresponds with reduced N<sub>2</sub>O emissions. Together, these results broaden our understanding on how plant-soil interactions drives N<sub>2</sub>O emissions processes and improves our ability to identify optimal plant-based emission mitigation approaches.</p></div>","PeriodicalId":21888,"journal":{"name":"Soil Biology & Biochemistry","volume":null,"pages":null},"PeriodicalIF":9.8000,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0038071724002372/pdfft?md5=7cfd9294491fb8a994c784ade33b6f15&pid=1-s2.0-S0038071724002372-main.pdf","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Soil Biology & Biochemistry","FirstCategoryId":"97","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0038071724002372","RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"SOIL SCIENCE","Score":null,"Total":0}
引用次数: 0
Abstract
Mitigation of N2O emissions, a potent greenhouse gas, remain challenging due to knowledge gaps in plant-mediated nitrogen (N) transformation pathways, which limits ability to identify optimal approaches for efficient N utilization. We set up mesocosms with barley, Italian ryegrass, and barley in combination with Italian ryegrass to assess role of cover crop in N2O emission mitigation. Soil emitted N2O was collected simultaneously from the pots with plants at three growth stages: namely, vegetative, canopy expansion, and grain filling. The gas sample N2O contents, N in microbial biomass (MBN), mineral N content, and phospholipid fatty acid (PLFA) analysis in soils were determined at the three growth stages. Cumulatively, highest N2O was emitted from soil under Italian ryegrass (0.056 mg N g−1 soil) followed by barley (0.0051 mg N g−1 soil) and the least under barley and Italian ryegrass combination (0.0014 mg N g−1 soil). The high emissions under Italian ryegrass occurred at vegetative stage due to high reactive N availability. Strong emissions were observed at canopy expansion stage under barley and were linked to access to the large mineral N proportion redistributed to the lower depth as depicted by highest MBN (0.025 mg N g−1 soil) and decreased extractable N (0.0068 mg N g−1 soil). The high emissions under barley correlated with high fungal/bacterial ratio, pointing towards a fungal role in the emissions. The least soil N2O emissions under barley and Italian ryegrass combination were accompanied by elimination of variations induced by the plant growth stages. Absence of 18:2ω6,9 fungal PLFA biomarker under barley and Italian ryegrass combination indicates a potential inhibition and corresponds with reduced N2O emissions. Together, these results broaden our understanding on how plant-soil interactions drives N2O emissions processes and improves our ability to identify optimal plant-based emission mitigation approaches.
期刊介绍:
Soil Biology & Biochemistry publishes original research articles of international significance focusing on biological processes in soil and their applications to soil and environmental quality. Major topics include the ecology and biochemical processes of soil organisms, their effects on the environment, and interactions with plants. The journal also welcomes state-of-the-art reviews and discussions on contemporary research in soil biology and biochemistry.