The Center for Agroforestry, School of Natural Resources, 302 Anheuser-Busch Natural Resources Building, University of Missouri-Columbia, Columbia, MO 65211, USA; Department of Agricultural, Food and Environmental Sciences, Università Politecnica delle Marche, 60131 Ancona, Italy.
Department of Agricultural, Food and Environmental Sciences, Università Politecnica delle Marche, 60131 Ancona, Italy.
Sci Total Environ. 2024 Jan 1;906:167208. doi: 10.1016/j.scitotenv.2023.167208. Epub 2023 Sep 19.
Composting mitigates environmental risks associated with using solid digestate as fertilizer. However, evidence is lacking on benefits of using composted digestate as fertilizer in enhancing soil health and increasing agronomic yield compared to non-composted digestate (hereafter, digestate). A field study was conducted consisting of digestate, composted digestate, co-composted digestate with biogas feedstocks (corn [Zea mays L.] silage, poultry litter, corn silage + poultry litter or food processing by-product), inorganic nitrogen fertilizer, and control (no treatment applied) on soil microbial biomass, enzyme activities (EA), soil organic carbon (SOC), bioavailable P (P), total nitrogen (TN), soil health index (SHI), and sunflower (Helianthus annuus L.) yield. The Partial Least Square Path Model (PLS-PM) was used to predict: 1) nutrient cycling in response to changes in microbial growth and EA and 2) agronomic yield in response to SHI and soil nutrients dynamics. Composted digestate had equivalent soil health benefits with most of co-composted materials and digestate, albeit agronomic yield was greatest with composted digestate, which was 40 % and 100 % greater than with inorganic nitrogen fertilizer and digestate, respectively, indicating composted digestate's potential to replace the synthetic N fertilizer. Moreover, composts from a sole digestate, rather than the ones from co-composted with fresh feedsstocks, can be promising organic amendments and fertilizers for growing sunflower. The PLS-PM model identified that triggered microbial biomass growth and EA, following digestate and composted digestate applications, catalyzed organic matter decomposition, resulting in enhanced nutrients contents and soil health. However, the model revealed that improved SHI did not predict agronomic yield, as opposed to P and TN, suggesting agronomic performance may have been more sensitive to changes in specific soil nutrients status than the overall soil health condition. We conclude that the benefits of composted digestate as fertilizer hint the significance of digestate valorization via post-digestate composting and compost utilization for sustainability of the bioenergy sector.
堆肥可以减轻将固体消化物用作肥料所带来的环境风险。然而，缺乏使用堆肥消化物作为肥料与非堆肥消化物（以下简称消化物）相比，在增强土壤健康和提高农业产量方面的益处的证据。进行了一项田间研究，该研究包括消化物、堆肥消化物、沼气原料（玉米青贮、家禽粪便、玉米青贮+家禽粪便或食品加工副产品）共堆肥的消化物、无机氮肥和对照（未处理），研究对象为土壤微生物生物量、酶活性（EA）、土壤有机碳（SOC）、生物可利用磷（P）、总氮（TN）、土壤健康指数（SHI）和向日葵（Helianthus annuus L.）产量。偏最小二乘路径模型（PLS-PM）用于预测：1）微生物生长和 EA 变化引起的养分循环，2）SHI 和土壤养分动态引起的农业产量。尽管堆肥消化物的农业产量最高，但堆肥消化物与大多数共堆肥材料和消化物具有等效的土壤健康益处，其分别比无机氮肥和消化物高出 40%和 100%，这表明堆肥消化物有可能替代合成氮肥。此外，与新鲜饲料共堆肥的消化物制成的堆肥，而不是单独的消化物制成的堆肥，可以成为有前途的有机改良剂和向日葵肥料。PLS-PM 模型确定，在应用消化物和堆肥消化物后，触发微生物生物量生长和 EA 的因素会促进有机质分解，从而提高养分含量和土壤健康。然而，该模型表明，改善 SHI 并不能预测农业产量，而 P 和 TN 可以，这表明农业表现可能对特定土壤养分状况的变化比整体土壤健康状况更为敏感。我们得出结论，堆肥消化物作为肥料的益处表明了通过消化物后堆肥和堆肥利用使消化物增值对生物能源部门可持续性的重要性。
