Department of Physics and Earth Science, University of Ferrara (UNIFE), Via Saragat 1, 44122, Ferrara, Italy.
Department of Chemical, Pharmaceutical and Agricultural Sciences, University of Ferrara (UNIFE), Via Luigi Borsari 46, 44121, Ferrara, Italy.
Chemosphere. 2023 Mar;317:137881. doi: 10.1016/j.chemosphere.2023.137881. Epub 2023 Jan 16.
Recycling nutrients is of paramount importance. For this reason, struvite and nitrogen enriched zeolite fertilizers produced from wastewater treatments are receiving growing attention in European markets. However, their effects on agricultural soils are far from certain, especially struvite, which only recently was implemented in EU Fertilizing Product Regulations. In this paper, we investigate the effects of these materials in acid sandy arable soil, particularly focusing on N dynamics, evaluating potential losses, transformation pathways, and the effects of struvite and zeolitic tuffs on main soil biogeochemical parameters, in comparison to traditional fertilization with digestate. Liming effect (pH alkalinization) was observed in all treatments with varying intensities, affecting most of the soil processes. The struvite was quickly solubilized due to soil acidity, and the release of nutrients stimulated nitrifying and denitrifying microorganisms. Zeolitic tuff amendments decreased the NO gas emissions, which are precursors to the powerful climate altering NO gas, and the N enriched chabazite tuff also recorded smaller NH emissions compared to the digestate. However, a high dosage of zeolites in soil increased NH emissions after fertilization, due to pronounced pH shifts. Contrasting effects were observed between the two zeolitic tuffs when applied as soil amendments; while the chabazite tuff had a strong positive effect - increasing up to ∼90% the soil microbial N immobilization - the employed clinoptilolite tuff had immediate negative effects on the microbial biomass, likely due to the large quantities of sulphur released. However, when applied at lower dosages, the N enriched clinoptilolite also contributed to the increase of microbial N. From these outcomes, we confirm the potential of struvite and zeolites to mitigate the outfluxes of nutrients from agricultural systems. To gain the best results and significantly lower environmental impacts, extension practitioners could give recommendations based on the soils that are planned for zeolite application.
回收营养物质至关重要。出于这个原因，从废水处理中生产的鸟粪石和富含氮的沸石肥料在欧洲市场上受到越来越多的关注。然而，它们对农业土壤的影响还远未确定，特别是鸟粪石，它直到最近才被纳入欧盟肥料产品法规。在本文中，我们研究了这些材料在酸性砂质耕地土壤中的影响，特别是关注氮动态，评估潜在的损失、转化途径，以及鸟粪石和沸石凝灰岩对主要土壤生物地球化学参数的影响，与传统的粪便消化物施肥相比。在所有处理中都观察到了石灰效果（pH 碱化），其强度不同，影响了大多数土壤过程。由于土壤酸度，鸟粪石很快溶解，养分的释放刺激了硝化和反硝化微生物。沸石凝灰岩的添加减少了 NO 气体排放，NO 气体是强大的气候变化前体气体，富氮的 chabazite 凝灰岩与粪便消化物相比，也记录到较小的 NH 排放。然而，由于 pH 值的显著变化，土壤中高剂量的沸石在施肥后增加了 NH 排放。在作为土壤改良剂施用时，两种沸石凝灰岩表现出相反的效果；虽然 chabazite 凝灰岩对土壤微生物氮固定有很强的积极影响，最大增加幅度可达约 90%，但所用的斜发沸石凝灰岩对微生物生物量有立即的负面影响，这可能是由于释放了大量的硫。然而，当以较低的剂量施用时，富氮的斜发沸石也有助于增加微生物氮。从这些结果中，我们证实了鸟粪石和沸石在减轻农业系统中养分流失方面的潜力。为了获得最佳效果并显著降低环境影响，推广工作者可以根据计划应用沸石的土壤提出建议。
