用沼气消化物和生物炭替代矿物肥料会增加物理稳定的土壤碳，但不会增加田间试验中的作物生物量。
Substitution of mineral fertilizers with biogas digestate plus biochar increases physically stabilized soil carbon but not crop biomass in a field trial.
机构信息
University of Kassel, Department of Environmental Chemistry, Nordbahnhofstrasse 1a, 37213 Witzenhausen, Germany.
University of Nebraska-Lincoln, Department of Agronomy and Horticulture, 202 Keim Hall, Lincoln, NE 68583, USA.
出版信息
Sci Total Environ. 2019 Aug 25;680:181-189. doi: 10.1016/j.scitotenv.2019.05.051. Epub 2019 May 6.
Various organic amendments are scrutinized as potential agricultural management strategies to ensure soil productivity while mitigating climate change due to the accumulation of soil organic matter (OM). The objectives of this experiment were to study the effects of biochar and biogas digestate versus mineral fertilizer on crop aboveground biomass as well as fractions and mineralization of soil organic carbon (SOC). Samples of a sandy Cambisol were taken 14 months after establishment of a field experiment in Germany. Treatments included application of equal nitrogen in the form of mineral fertilizer or liquid biogas digestate without biochar (B), with 1 Mg biochar haseason for two growing seasons (B), or with 40 Mg biochar ha application (B). Soil fractionation in water separated water-extractable and free particulate (fPOM) OM, followed by sonification and sieving to isolate occluded particulate (oPOM) and < 20 μm aggregate-occluded and mineral-associated OM. CO emissions were measured during 92-day laboratory incubations at 10 and 20 °C. Analysis of variance found digestate lowered (p < 0.05) rye aboveground biomass compared to mineral fertilizer (9.3 vs. 10.6 Mg ha), while biochar had no effect. B treatments increased C mineralization during incubation by 16% and contained 3.8 times more SOC than B treatments. This additional SOC was allocated to fPOM (52%), oPOM (22%), and the <20 μm fraction (26%). Digestate application increased SOC content of oPOM by 11% compared to mineral fertilizer. Furthermore, combined application of 40 Mg biochar ha with digestate resulted in 20% more SOC in the <20 μm fraction than biochar with mineral fertilizer. The lack of a significant fertilizer or biochar-fertilizer interaction effect on C mineralization during incubation demonstrates the stability of SOC from digestate alone or in combination with biochar. The absence of significant differences in SOC content between B and B treatments demonstrates the difficulty of documenting SOC sequestration in the field at low biochar application rates.
各种有机肥料被视为潜在的农业管理策略，以确保土壤生产力，同时减轻由于土壤有机质（OM）积累而导致的气候变化。本实验的目的是研究生物炭和沼气消化物与矿物肥料对作物地上生物量以及土壤有机碳（SOC）的分数和矿化的影响。在德国进行田间实验 14 个月后采集了沙质 Cambisol 样本。处理包括以矿物肥料或液体沼气消化物的形式添加等量的氮，而不添加生物炭（B），两个生长季每公顷添加 1 Mg 生物炭（B），或每公顷添加 40 Mg 生物炭（B）。在水中进行土壤分馏，分离出可提取水和自由颗粒（fPOM）有机质，然后通过超声处理和筛分分离出封闭颗粒（oPOM）和<20 µm 团聚体封闭和矿物相关的 OM。在 10 和 20°C 下进行为期 92 天的实验室培养期间测量 CO 排放。方差分析发现，与矿物肥料相比，消化物降低了黑麦地上生物量（p<0.05），为 9.3 vs. 10.6 Mg ha，而生物炭则没有影响。B 处理在培养过程中增加了 16%的 C 矿化，并比 B 处理含有 3.8 倍更多的 SOC。这种额外的 SOC 分配到 fPOM（52%），oPOM（22%）和<20 µm 分数（26%）。与矿物肥料相比，消化物的应用增加了 oPOM 中 SOC 的含量 11%。此外，与生物炭和矿物肥料相比，单独使用 40 Mg 生物炭公顷与消化物的联合应用导致<20 µm 分数中的 SOC 增加了 20%。在培养过程中 C 矿化没有肥料或生物炭-肥料相互作用的显著影响，表明单独使用消化物或与生物炭结合的 SOC 具有稳定性。B 和 B 处理之间 SOC 含量没有显著差异表明，在低生物炭施用量下，在田间记录 SOC 固存具有一定难度。
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