Monitoring and Research Department, Metropolitan Water Reclamation District of Greater Chicago, 6001 West Pershing Road, Cicero, IL 60804, USA.
Monitoring and Research Department, Metropolitan Water Reclamation District of Greater Chicago, 6001 West Pershing Road, Cicero, IL 60804, USA.
Sci Total Environ. 2024 Jul 15;934:173216. doi: 10.1016/j.scitotenv.2024.173216. Epub 2024 May 21.
Information about impacts of long-term biosolids application on soil microbial populations and functional groups and N cycling is important for evaluating soil health and agroecosystem sustainability under long-term biosolids application. Mine spoil plots received annual biosolids application from 1973 to 2010 at low (16.8 Mg ha yr), medium (33.6 Mg ha yr), and high rates (67.2 Mg ha yr). A no-biosolids control received chemical fertilizer at the agronomic rate. Soil samples were collected in three seasons per year spanning 2003-2005 for measuring soil moisture, pH, soil organic C (SOC), total and extractable heavy metals (Cd, Cu, Ni, Zn), NO, N mineralization potential (NMP), microbial biomass C (MBC), and populations of three N-cycling bacteria (NCB) groups: ammonia-oxidizing bacteria (AOB), nitrite-oxidizing bacteria (NOB), and denitrifying bacteria (DNB). Soil samples were collected again in 2008 and 2010 for quantifying total and extractable heavy metals, and in 2018 (eight years after biosolids applications ended) for measuring SOC, MBC, NMP, and microbial respiration. During 2003-2005, mean MBC was 315, 554, 794, and 1001 mg kg in the control, low, medium, and high biosolids treatments, respectively. Populations of NCB did not differ among treatments. Biosolids application increased total and extractable metal concentrations but the effect of biosolids rates were much lower on extractable than total concentrations. Soil extractable Cd and Cu concentrations decreased from medium to high applications, likely due to complexing with biosolids organic matter. Partial least squares regression analysis identified a strong positive effect on MBC of SOC and a weak negative effect of Cu, explaining the strong net positive effect of biosolids on MBC. In 2018, the medium and high biosolids treatments maintained higher SOC, MBC, NMP, and microbial respiration than the control. This study provided further evidence that long-term biosolids application has positive effects on soil microbes that persist for years after ending application.
长期生物固体应用对土壤微生物种群和功能群以及氮循环的影响的信息对于评估长期生物固体应用下的土壤健康和农业生态系统可持续性非常重要。从 1973 年到 2010 年，矿山废料场每年接受低（16.8 Mg ha yr）、中（33.6 Mg ha yr）和高（67.2 Mg ha yr）生物固体的应用。没有生物固体的对照处理按农业率接受化肥。从 2003 年到 2005 年，每年在三个季节采集土壤样本，以测量土壤水分、pH 值、土壤有机碳 (SOC)、总提取和可提取重金属 (Cd、Cu、Ni、Zn)、NO、氮矿化潜力 (NMP)、微生物生物量 C (MBC) 和三种氮循环细菌 (NCB) 群体的种群：氨氧化细菌 (AOB)、亚硝酸盐氧化细菌 (NOB) 和反硝化细菌 (DNB)。2008 年和 2010 年再次采集土壤样本以测量总提取和可提取重金属，2018 年（生物固体应用结束后八年）测量 SOC、MBC、NMP 和微生物呼吸。在 2003 年至 2005 年期间，对照、低、中、高生物固体处理的 MBC 均值分别为 315、554、794 和 1001 mg kg。NCB 种群在处理之间没有差异。生物固体的应用增加了总提取和可提取金属的浓度，但生物固体速率对可提取浓度的影响远低于总浓度。从中等到高的应用中，土壤可提取 Cd 和 Cu 的浓度降低，这可能是由于与生物固体有机物的络合。偏最小二乘回归分析确定了 SOC 对 MBC 的强烈正向影响和 Cu 的微弱负向影响，解释了生物固体对 MBC 的强烈净正向影响。2018 年，中高生物固体处理比对照保持更高的 SOC、MBC、NMP 和微生物呼吸。本研究进一步证明，长期生物固体应用对土壤微生物具有积极影响，这种影响在应用结束多年后仍然存在。
