Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
School of Environment, Beijing Normal University, Beijing 100875, China.
Sci Total Environ. 2022 Dec 20;853:158620. doi: 10.1016/j.scitotenv.2022.158620. Epub 2022 Sep 6.
Biochar and nitrogen (N) fertilizer application can increase soil carbon sequestration and enhance soil nutrient cycling. However, few studies have systematically explored the effects of the long-term application of biochar and N fertilizer on soil multifunctionality and characterized its driving factors. Based on an 8-year biochar paddy-field experiment in anthropogenic alluvial alkaline soil in northwest China, we measured eleven soil functions associated with soil carbon sequestration and nutrient cycling and four potential factors (soil bacterial and fungal richness, pH, and aggregates) governing soil functions to investigate the effects of three biochar rates (C0, no biochar; C1, 4.5 t ha year; C2, 13.5 t ha year) and two N fertilizer rates (N0, no N fertilizer; N1, 300 kg N ha year) on individual soil ecosystem functions and soil multifunctionality. Our results showed that biochar and N fertilizer application increased soil organic carbon (SOC) by 20-58 % and total N content by 9.3-15 % and had a varied effect (but mainly positive) on the activity of enzymes associated with soil carbon, N, and phosphorus cycling. Different application rates of biochar and N fertilizer had no influence on soil DNA concentrations, but did change soil microbial diversity, soil aggregation, and pH. The carbon storage function (SOC content) of soils is an important predictor of multifunctionality. Long-term biochar and N fertilizer application indirectly explained soil multifunctionality by altering soil pH, whereas bacterial and fungal diversity and soil aggregates did not play significant roles in explaining soil multifunctionality. These findings suggest that the application of biochar and N fertilizer can enhance soil multifunctionality by directly improving the individual functions [soil carbon sequestration (SOC content)] and decreasing soil pH in alkaline paddy fields.
生物炭和氮肥的施用可以增加土壤碳固存，增强土壤养分循环。然而，很少有研究系统地探讨长期施用生物炭和氮肥对土壤多功能性的影响，并对其驱动因素进行了描述。本研究基于中国西北人为冲积碱性土壤中进行的为期 8 年的生物炭稻田试验，我们测量了与土壤碳固存和养分循环相关的 11 种土壤功能，以及控制土壤功能的 4 个潜在因素（土壤细菌和真菌丰富度、pH 值和团聚体），以研究三种生物炭施用量（C0，不施生物炭；C1，4.5 t ha-1 yr-1；C2，13.5 t ha-1 yr-1）和两种氮肥施用量（N0，不施氮肥；N1，300 kg N ha-1 yr-1）对单个土壤生态系统功能和土壤多功能性的影响。结果表明，生物炭和氮肥的施用使土壤有机碳（SOC）增加了 20-58%，总氮含量增加了 9.3-15%，并对与土壤碳、氮和磷循环相关的酶活性产生了不同的影响（但主要是积极的）。不同施用量的生物炭和氮肥对土壤 DNA 浓度没有影响，但改变了土壤微生物多样性、土壤团聚体和 pH 值。土壤碳储存功能（SOC 含量）是土壤多功能性的一个重要预测因子。长期施用生物炭和氮肥通过改变土壤 pH 值间接解释了土壤多功能性，而细菌和真菌多样性以及土壤团聚体在解释土壤多功能性方面没有发挥重要作用。这些发现表明，生物炭和氮肥的施用可以通过直接改善单个功能（土壤碳固存[SOC 含量]）和降低碱性稻田土壤的 pH 值来增强土壤多功能性。
