Johansen Jesper Liengaard, Dam Marie, Kudjordjie Enoch Narh, Santos Susana Silva, Palmqvist Annemette, Magid Jakob, Vestergård Mette
Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK1871 København, Denmark; Department of Agroecology, AU-Flakkebjerg, Aarhus University, Forsøgsvej 1, DK4200 Slagelse, Denmark; Department of Science and Environment, Roskilde University, Universitetsvej 1, PO Box 260, DK4000 Roskilde, Denmark.
Danish Agricultural Agency, Ministry of Food, Agriculture and Fisheries of Denmark, Nyropsgade 30, DK1780 Copenhagen, Denmark.
Sci Total Environ. 2023 Feb 20;860:160485. doi: 10.1016/j.scitotenv.2022.160485. Epub 2022 Nov 25.
It is desirable to recycle the urban waste products human urine, composted household waste and sewage sludge as fertilizers to agricultural fields. This could minimize the use of NPK fertilizer, improve soil structure and store carbon. However, waste products may contain heavy metals, persistent organic pollutants (POP) and plastics, and there are concerns that long-term build-up of these substances will cause unwanted effects on soil health. Nematodes are ubiquitous and numerous in soil ecosystems. Abundance and community structure of soil nematodes can be used as indicators of soil health, as some species are vulnerable to pollution. There are well-developed methods for detecting environmental changes based on nematode community structure. At the long-term CRUCIAL field experiment, where alternative fertilizer products have been applied since 2003, we measured effects of long-term fertilization with human urine, composted household waste and sewage sludge on soil properties (pH, soil organic matter and nitrogen availability), abundance of soil microorganisms (bacteria, fungi, small protozoa and ciliates) and nematode trophic groups compared to plots with unfertilized, NPK and cattle manure treatment. Sampling and assessments were done three times during a growth season. Further, we assessed the composition of nematode communities using metabarcoding. Treatments with a high input of organic matter (cattle manure, composted household waste and sewage sludge) had high abundances of bacteria and thus bacterial grazers (small protozoa, ciliates, and bacterial feeding nematodes). We found a significant correlation between nematode community structure and pH and organic matter. We calculated the nematode Maturity Index 2-5 (pollution indicator) based on metabarcoding data, which did not differ significantly between the treatments. We conclude that long-term fertilization with different types of contemporary Danish urban waste products affects both soil properties and abundance of soil organisms, the latter largely reflecting the organic matter input of the fertilizer treatments. We found no adverse effect on nematode communities that could indicate pollution-induced stress on nematofauna or decreased soil fertility.
将城市废弃物（人类尿液、堆肥化的家庭垃圾和污水污泥）作为肥料回用于农田是很有必要的。这可以减少氮磷钾肥料的使用，改善土壤结构并储存碳。然而，废弃物可能含有重金属、持久性有机污染物（POP）和塑料，人们担心这些物质的长期积累会对土壤健康产生不良影响。线虫在土壤生态系统中无处不在且数量众多。土壤线虫的丰度和群落结构可以用作土壤健康的指标，因为一些物种易受污染影响。基于线虫群落结构检测环境变化的方法已经很成熟。在长期的关键田间试验中，自2003年以来一直施用替代肥料产品，我们测量了长期施用人类尿液、堆肥化的家庭垃圾和污水污泥对土壤性质（pH值、土壤有机质和氮有效性）、土壤微生物（细菌、真菌小原生动物和纤毛虫）丰度以及线虫营养类群的影响，并与未施肥、施用氮磷钾肥料和牛粪处理的地块进行了比较。在一个生长季节内进行了三次采样和评估。此外，我们使用宏条形码技术评估了线虫群落的组成。高有机质投入处理（牛粪、堆肥化的家庭垃圾和污水污泥）中细菌丰度高，因此细菌捕食者（小原生动物、纤毛虫和食细菌线虫）也较多。我们发现线虫群落结构与pH值和有机质之间存在显著相关性。我们根据宏条形码数据计算了线虫成熟度指数2 - 5（污染指标），各处理之间没有显著差异。我们得出结论，长期施用不同类型的当代丹麦城市废弃物会影响土壤性质和土壤生物的丰度，后者在很大程度上反映了肥料处理的有机质投入。我们没有发现对线虫群落有不利影响，这可能表明对线虫动物群有污染诱导的压力或土壤肥力下降。
