Organic fertilization promotes the accumulation of soil particulate organic carbon in a 9-year plantation experiment

10 páginas.- 5 figuras.- referenciasManagement practices are expected to influence the capacity of forests to mitigate climate change. However, the long-term effects of afforestation on soil carbon accumulation in response to contrasting management regimes remain poorly understood. Here, we combined organic matter fractionation with a nine-year-long organic fertilization experiment to investigate the influences of largely accepted practices such as biochar (BC) and biogas-slurry (BS) inputs on the accumulation of soil particulate organic carbon (POC) and mineral-associated organic carbon (MAOC) in three soil horizon depths (0–25, 25–50, and 50–75 cm, respectively). Our results suggested that both BS and BC significantly enhanced the POC and total soil organic carbon (SOC) content but overall did not significantly influence MAOC. Moreover, the POC and MAOC was more responsive to BS than BC. Further, our analyses revealed that the effects of BC on POC and MAOC were indirectly regulated by changes in the SOC: total nitrogen (TN) ratio, while BS influenced POC and MAOC by regulating TN. However, the responses of MAOC to the infiltration of organic fertilizers into the mineral soil should not be ignored, especially under high BC levels. Our work revealed that management practices are critical for supporting the long-term capacity of new forests to accumulate soil carbon, thereby facilitating the provision of nature-based solutions in response to climate change.This study was supported by the National Key Research and Development Program of China (No. 2021YFD2200403, 2016YFD0600204),the National Natural Science Foundation of China (No. 32071594,32101339), and the key project of the open competition in JiangsuForestry (LYKJ[2022]01). Manuel Delgado-Baquerizo was supportedby a project from the Spanish Ministry of Science and Innovation(PID2020-115813RA-I00), and a project of the Fondo Europeo de Desarrollo Regional (FEDER), and the Consejería de Transformación Económica, Industria, Conocimiento y Universidades of the Junta de Andalucía (FEDER Andalucía 2014-2020 Objetivo temático“01—Refuerzo de la investigación, el desarrollo tecnológico y lainnovaci on”) associated with the research project P20_00879 (ANDABIOMA). Tingting Ren acknowledges the support of the Chinese Scholarship Council (CSC)Peer reviewe

Soil fauna alter the responses of greenhouse gas emissions to changes in water and nitrogen availability

8 páginas.- 5 figuras.- 1 tabla.- referencias.- Supplementary data to this article can be found online at https://doi. org/10.1016/j.soilbio.2023.108990Fertilization and drought are two of the most important global change drivers that impacting greenhouse gas (GHG) emissions. Soil organisms are among the fundamental biotic drivers of biogeochemical cycles and can play critical roles in mitigating global change. However, the contributions of soil macrofauna in explaining the responses of GHG emissions to fertilization and drought remain poorly understood. Here, we designed a three-factor microcosm experiment to examine how soil macrofauna (no fauna, earthworms, and millipedes) alter the responses of CO2, N2O, and CH4 emissions, as well as the C and N contents in response to contrasting levels of N (N0: without N addition, N+: N addition) and available soil water (40% and 60% of soil water holding capacity). We show that soil fauna were significant regulators of CO2 and N2O emissions in response to changes in water and N availability, as supported by multiple identified statistical interactions. Millipedes were observed to reduce the positive influence of soil water availability on soil CO2 emissions in response to the addition of N. Similarly, earthworms weakened the effects of elevated N and water availability on soil N2O emissions. Moreover, CH4 emissions occurred only when millipedes were present. The structural equation models revealed that earthworms and millipedes modified soil CO2 and N2O emissions through their influences on soil total dissolved nitrogen and microbial biomass carbon. Overall, this study demonstrated that soil macrofauna can notably mediate the responses of GHG emissions and soil biogeochemical cycles to global environmental changes.This study was supported by the National Natural Science Foundation of China (Grant No. 32101339 and 32071594), and partially by the National Key Research and Development Program of China (2021YFD2200403, 2016YFD0600204) and the Key Subject of Ecology of Jiangsu Province (SUJIAOYANHAN❲2022❳No.2). M.D-B. acknowledges support from the Spanish Ministry of Science and Innovation for the I + D + i project PID2020-115813RA-I00 funded by MCIN/AEI/10.13039/501100011033. M.D-B. is also supported by a project of the Fondo Europeo de Desarrollo Regional (FEDER) and the Consejería de Transformación Económica, Industria, Conocimiento y Universidades of the Junta de Andalucía (FEDER Andalucía 2014–2020 Objetivo temático “01 - Refuerzo de la investigación, el desarrollo tecnológico y la innovación”) associated with the research project P20_00879 (ANDABIOMA). HYHC acknowledges support from the Natural Sciences and Engineering Research Council of Canada (RGPIN-2019–05109 and STPGP506284) and the Canada Foundation of Innovation and Ontario Research Fund (CFI36014).Peer reviewe